External Sensors

Inputs and Outputs

The UNI provides two configurable input/output (IO) channels that can be used for measuring voltages, counting pulses, measuring frequency and duty cycle, controlling external devices, and interfacing to 1-Wire sensors.

Pin	Name	Description
4	IO1	Digital input, pulse input, 1-Wire, and output
5	IO2	Voltage input, and output

The available functions are summarised below.

Function	IO1	IO2
Digital measurement	X
Voltage measurement		X
Pulse count	X
Frequency	X
Duty cycle	X
Wake on change	X	X
Switch to GND	X	X
Pullup	X
1-Wire	X

General IO Settings

Each IO can be configured independently.

Measurement Interval

Measurements can be scheduled as a multiple of the base interval. The fastest possible measurement rate is achieved by setting the Interval to 1, in which case measurements will occur on every base interval. To reduce power consumption, the measurement rate can be reduced by increasing the Interval. To disable an IO, set the Interval to 0.

Default State

The default state determines the output state of an IO between measurement cycles.

Note

The state of an IO may deviate from the settings if being controlled by a script.

Measurement State

The measurement state determines the state of an IO during a measurement cycle.

Measurement Time

The measurement time determines how long the device hold the IO in the measurement state before taking a measurement. This allows attached sensors to boot, or for measurements to settle before being measured.

IO1

IO1 supports digital measurement, pulse counting, frequency measurement, duty cycle measurement, wake-on-change, 1-Wire communications, and output switching.

Digital inputs are measured using a threshold of approximately 2V. Voltages below the threshold are interpreted as OFF and voltages above the threshold are interpreted as ON.

Pulse counting can be used with flow meters, rain gauges, energy meters, run sensors, and other pulse-output devices. Frequency and duty cycle measurements use the same pulse measurement circuitry.

Many pulse-output sensors, including reed-switch flow meters and rain gauges, use open-collector outputs or voltage-free contacts that switch to ground. In these applications, the internal pullup resistor can be enabled to provide the required bias voltage for pulse detection.

For low-power applications, IO1 may be configured to wake the device when the input changes state.

IO2

IO2 supports voltage measurement, wake-on-change, and output switching.

Voltage measurements may be calibrated into end-use engineering units. For example, a 0-10V level transmitter representing a water level of 0-1m can be configured so that the measured value is reported directly in metres. This allows sensor outputs to be displayed and alarmed in meaningful application units rather than raw voltages.

For low-power applications, IO2 may be configured to wake the device when the input changes state.

Output Functions

The IO can also be used as outputs and can be switched to:

• OFF - High impedance.

• GND - Connects the IO to ground.

• PULLUP - Enables an internal pullup resistor (IO1 only).

OFF disconnects all internal sources from the IO, leaving the pin in a high impedance state.

GND connects the IO to ground through a protected low-side switch and is typically used to activate relays, alarms, indicators, contactors, and other externally powered devices.

PULLUP enables an internal pullup resistor to 3.3V and is typically used with voltage-free contacts, reed switches, and open-collector outputs.

Output Characteristics

Each IO output can switch voltages up to 32V and sink currents up to 250mA.

The outputs are protected against overloads, short circuits, electrostatic discharge, inductive transients, and excessive temperature. If a fault condition occurs, the output automatically protects itself and will automatically resume operation when the fault is removed.

Switching a resistive load

The IO are capable of switching inductive loads such as relays and solenoids; however, flyback diodes should always be fitted to inductive loads to minimise electrical stress and improve system reliability.

Switching a high inductance load

Pulse Measurement

IO1 can be used to measure pulse count, frequency, and duty cycle.

Pulse counting records the number of input transitions occurring during the measurement period. Frequency measurement determines the pulse repetition rate, while duty cycle measurement determines the proportion of time the signal remains active.

Input transitions are detected when the signal crosses the digital input threshold of approximately 2V.

For reliable operation, input signals should transition cleanly through the threshold voltage and excessive noise around the threshold should be avoided.

The figure shows how to wire a flow meter with a reed-switch using the internal pullup on the UNI-Z1.

Pulse counting

Wake on Change

Wake-on-change allows the UNI to wake from low-power sleep modes when an input changes state.

This feature is particularly useful when monitoring alarm contacts, limit switches, float switches, reed switches, pulse-output sensors, and other event-driven inputs that require immediate response. In many of these applications, the internal pullup resistor on IO1 can be enabled, allowing the sensor to pull the input low when activated.

Calibration

Calibration can be applied to each measurement so that the value returned by the Senquip UNI-Z1 is in units that are meaningful in the end application. For instance, a level sensor that outputs a voltage between 0 and 10V may represent a water level between 0 and 1 metre. The voltage measurement can be calibrated to convert from volts to the more meaningful unit of metres.

In any system, the measurement instrument (the Senquip UNI-Z1), the sensor, and possibly the measured value will be subject to errors that may accumulate to reduce accuracy. To achieve an accurate and meaningful measurement, a calibration can be performed.

In this example, the tank could be calibrated by measuring the sensor output at two known levels. At a level of 0.1m, the measured voltage may be 1.05V. At a level of 0.8m, the measured voltage may be 8.12V. The calibration would then be filled into the IO setting as shown below:

Low In	1.05	This is the value in volts measured by the Senquip UNI-Z1
Low Out	0.1	This is the actual value that we would like to report
High In	8.12	This is the value in volts measured by the Senquip UNI-Z1
High Out	0.8	This is the actual value that we would like to report
Unit	m	The unit to be reported is metres

Warnings and Alarms

For each measurement type, high and low warning and alarm levels can be set. Once enabled, each time a measurement is completed, the returned value will be compared with low and high warning and alarm thresholds. If a warning or alarm level is breached, a message will immediately be transmitted. As long as the warning or alarm condition persists, messages will be transmitted at the exception-interval rather than the transmit-interval.

Note

If calibration has been applied, then the warning and enable thresholds should be set in the calibrated units.

To set a high level warning or alarm only, set the low level to a value that is impossible to achieve. For instance, to set a high-only warning at 50V, set the low warning to -1V, which is an unachievable value.

Hysteresis can be specified in increments of the specified unit, to prevent multiple alarms in the presence of electrical noise.

Hysteresis

1-Wire

IO1 can be configured for 1-Wire communication by selecting 1WIRE as the IO1 Default State. When 1-Wire is enabled, IO1 is dedicated to 1-Wire operation and all other IO1 measurement and output functions are disabled.

1-Wire is commonly used by digital temperature sensors, identification devices, and other low-speed digital sensors.

The 1-Wire data line is connected to IO1. Multiple 1-Wire devices can share the same bus as each device contains a unique factory-programmed address.

iButton reader connected to IO1

Communication with 1-Wire devices is performed entirely from script. The script is responsible for discovering devices, selecting addresses, issuing commands, reading responses, and dispatching measurements.

Note

Some 1-Wire devices support parasite power operation. Where reliable operation is important, powering sensors from an external supply is recommended.

Scripting

The IO can be controlled directly from scripts.

Scripts can read measurements and change output states.

Warning

If an IO is enabled in the settings and is also used in a script, the behaviour of that IO will be affected by both the settings and the script.

Note

In sleep and hibernate modes, the outputs default to OFF. If a pullup has been enabled, it will remain active during sleep and hibernate.

Specification

Parameter	Specification
Output
Open circuit voltage maximum	32V
GND sink current maximum	250mA per pin
Pullup resistor	33k to 3.3V
IO terminal input impedance to ground (without pullup)	>250k ohms
Voltage Measurement (IO2)
Voltage ADC Type	12 bit SAR
Voltage range	1.5-32VDC
Voltage measurement resolution	10mV
Voltage measurement accuracy	TBD
Threshold for IO to wake from hibernate	2.0V +/-0.5V
Frequency and Pulse
Frequency measurement range	TBD
Frequency measurement accuracy	TBD
Pulse counting detection threshold	2.0V +/-0.5V
Pulse counting maximum frequency in sleep	TBD
Pulse counting maximum frequency always on	TBD
Pulse minimum width	TBD
Duty cycle measurement range	0% to 100%
Duty cycle accuracy	TBD

Note

Due to the characteristics of the ADC used by the UNI-Z1, input voltages below approximately 1.5V on IO2 will be reported as 0V.

Serial interface

The serial port can be used to capture data that is sent from an external system or to interface to a MODBUS sensor.

The UNI-Z1 provides an RS485 interface on pins 2 and 7 of the header. The pin functions are shown in the table below. When required, an optional 120Ω termination resistor can be enabled in the settings.

Pin	Function
2	RS485-B
7	RS485-A

Note

RS485-B is sometimes referred to as D+ or TX+/RX+ and RS485-A as D- or TX-/RX-.

The serial interface supports RS485 operation.

The interface incorporates protection features to improve robustness and reliability in industrial environment with the RS485 receiver offering full failsafe operation for floating, shorted, or terminated inputs.

Specification

Parameter	Specification
RS485 differential output voltage (minimum with load resistance 120Ω)	+2V
RS485 differential input threshold (typical)	+/-200mV
Maximum nodes in RS485 mode	256
RS485 termination resistor	120Ω
ESD protection	+/-16kV

Settings

Measurements can be scheduled as a multiple of the base-interval. The fastest possible measurement rate is achieved by setting the interval to 1 in which case measurements will occur on every base interval. To reduce power consumption, the measurement rate can be turned down by increasing the interval.

In serial capture mode the measurement interval can be used to reduce the number of readings being provided by a connected sensor or system that may be permanently powered. If for instance, a connected system is sending a message every second but it is only required to be read and transmitted every minute, the measurement interval can be set to 1 minute in which case the device will wake on the minute interval, receive a message and return to sleep thereby missing the other 59 messages sent by the attached system. Since serial packets cannot be interrogated by the UNI-Z1 without a customised script, it makes sense to set the measurement interval to the same as the transmit interval in most cases.

An optional 120Ω RS485 termination resistor can be selected by selecting the Termination resistor option. The purpose of the termination resistor is to match the impedance of a transmission line to the hardware impedance of the interface to which it is connected. Termination is generally not required in lower speed networks (9600 baud or less) and networks shorter than 500m in length. No more than 2 termination resistors should be used, one at each end of the RS485 transmission line.

A baud rate of 4800, 9600, 19200, 38400, 56800 or 115200 needs to be selected using the baud rate option. Other settings, including the number of bits, odd or even parity and 1 or 2 stop bits are added in the settings field. The most common setup is 8 bits, no parity and 1 stop bit or “8N1”.

The serial interface can be configured in serial capture mode or MODBUS mode using the mode option. Capture mode is typically used where an external sensor sends serial data and a portion of that serial data is to be captured. MODBUS mode is used to connect to external sensors that are compatible with the MODBUS standard.

In serial capture mode The device listens for periodic data and when received, transmits this data at the next send interval. The maximum length of a message that can be captured is 512 characters. Once 512 characters have been received, the UNI-Z1 will terminate the capture and will transmit it on the next transmit interval.

In capture mode, the max-time setting can be used to set a timeout after which the serial port will return to sleep. Max-time can be used as a way to end serial measurement in the event that no serial data is received, or as a mechanism to allow the device to sample the serial port for a defined time-period.

Note

If the serial port needs to be kept on all the time, set the max-time to longer than the measurement interval. The contents of the serial buffer is retained as long as the device does not return to sleep.

The operation of the max chars option is similar to the max time setting except that the serial port stops sampling after a certain number of characters has been received. In most cases where the max-chars setting is used to terminate serial capture, the max-time setting is also used to end the serial measurement in the event that data does not arrive.

In Serial capture mode, in systems where many messages are sent and only a few are of interest, a start string of up to 10 characters can be enabled. For instance, in a typical GPS serial NMEA feed, the following are a subset of available messages:

• DTM - Datum being used.

• GGA - Fix information

• GLL - Lat/Lon data

• GSA - Overall Satellite data

• GSV - Detailed Satellite data

• RMC - Recommended minimum data for GPS

• RTE - Route message

• VTG - Vector track an Speed over the Ground

If in the application, the user is only interested in receiving the GGA message, then a start string can be set to GGA. In that way, any messages starting with DTM, GLL, GSA or other unwanted messages will be discarded.

Note

If a start string is enabled, the device will stay awake until the string is received or until the max-time is reached.

In firmware revisions less than 2, serial start strings are specified as text, with special characters such as carriage return and line feed being specified by their respective escape sequences. A list of allowable escape sequences is given below:

• \f Form-feed

• \n Newline (Line Feed)

• \r Carriage Return

• \t Horizontal Tab

• \v Vertical Tab

• \\ Backslash

Note

Because escape sequences start with a backslash (\), if a capture string contains a backslash, it needs to be escaped and so is represented as a double backslash (\\).

In firmware release 2 and above, serial start strings are specified as text, with special characters such as carriage return and line feed being specified by their respective ASCII codes in hexadecimal. A list of example hexadecimal sequences is given below:

• \x0C Form-feed

• \x0A Newline (Line Feed)

• \x0D Carriage Return

• \x09 Horizontal Tab

• \x0B Vertical Tab

• \x08 Backslash

The change to the method used to represent special characters has been made to allow for all ASCII characters to be used, and to allow for hexadecimal data to be captured.

Note

In firmware revisions 2 and lower, special characters are specified as escape characters. In revisions 2 and above, special characters are represented by their ASCII representations in hexadecimal.

In some serial protocols, the start of a packet is specified by a preceding period of inactivity on the serial bus. The Idle Time Before Start parameter can be used to specify an idle time, which is exceeded will trigger the serial port to start capturing serial data.

Note

If the serial port is capturing data and a subsequent idle time occurs, the capture process will restart and captured data will be discarded.

A serial capture stop string of up to 10 characters can also be provided. Again using the NMEA example, all NMEA messages end with a carriage return and line feed and so the serial capture stop strings in each case will be the same and will be “\r\n” or \x0D\x0A in revision 2 and above firmware. In most instances, the serial stop strings will be the same for all messages.

Note

If a start string is specified without a stop string, or the stop string is never encountered, the serial port will capture characters until the max-time or max-chars is reached, the next measurement interval occurs or 256 characters are received.

An optional serial request string can be sent, on each measurement interval, to an external device. The purpose of the request sting is to request data from an external sensor or system. The request string can be a maximum of 10 characters and can be entered as text. Special characters like carriage return and line feed can be inserted using escape sequences or their ASCII representations as described earlier in the chapter.

The UNI-Z1 implements the MODBUS communications protocol standard as a master, which enables communication with many slave devices connected to the network. The UNI-Z1 can be configured to periodically request specific data from slave MODBUS devices on the network and transmit that data at specified intervals.

Up to fifty MODBUS data requests can be configured; these data requests can either be from individual slave devices or multiple requests from the same device. For each of the fifty data reads, the slave address, function and register address need to be specified. The slave address will be specified by the manufacturer of the device that is attached to the UNI-Z1; in some cases, slave devices allow their addresses to be configured. The function specifies the type of data to be read from the slave device. The UNI-Z1 supports the following types of data reads:

• Disabled - the particular MODBUS channel is not used

• Read Coil - a 1 bit data value

• Read Discrete - a 1 bit data value

• Read Holding - a single 16 bit holding register

• Read Input - a 16 bit input register

• Read Holding (32 bits, Little Endian register order) - a 32 bit holding register

• Read Holding (32 bits, Big Endian register order) - a 32 bit holding register

• Read Input (32 bits, Little Endian register order) - a 32 bit input register

• Read Input (32 bits, Little Endian register order) - a 32 bit input register

Endianness is the order or sequence of bytes of digital data in computer storage and will be specified by the sensor that is being connected to the UNI-Z1.

A single MODBUS device may have multiple data values that can be read. The register address specifies which data the slave device needs to deliver.

In MODBUS mode, calibration can be applied so that the registers read by the UNI-Z1 can be scaled to be in the units of what is being measured. For instance, a register that returns 0 to 255 may represent 0% humidity to 100% humidity. The UNI-Z1 can be calibrated to take a number and to convert it to humidity in % and return that as the measured value.

In any system, the sensor and possibly the measured value will be subject to errors that may accumulate to reduce accuracy. In a system that uses the UNI-Z1 to measure fluid volume in a 100 litre tank using a MODBUS sensor, the sensor may have offset errors such that with zero liquid in the tank, the UNI-Z1 is showing a small volume. The UNI-Z1 and sensor may also not be perfectly linear in that they may not measure 1 litre in exactly the same way when the tank is empty versus when it is full. The tank itself may also not be perfectly manufactured and may, for instance have walls that are not perfectly straight. All of these errors could add together such that the final system is less accurate than expected. To achieve a more accurate system, a calibration can be performed. In this example, the tank could be calibrated by adding a small amount of liquid, say 10 litres (low Y) and noting the value reported by the UNI-Z1 (low X). Now fill the tank by adding another 99 litres (high y) and note the value being reported by the UNI-Z1 (high X). By filling the high and low X and Y values into the calibration constants associated with analog mode, offset and non-linearity errors can be eradicated, resulting in a much more accurate system.

In MODBUS mode, warning and alarm thresholds for can be set for each MODBUS channel. Once enabled, each time a measurement is completed, the returned value will be compared with minimum and maximum warning and alarm thresholds. If a warning or alarm level is breached, a message will immediately be transmitted. As long as the warning or alarm condition persists, messages will be transmitted at the exception-interval rather than the transmit-interval.

Note

If calibration has been applied, then the warning and enable thresholds are in the calibrated units.

A full list of serial interface settings is given in the table at the end of the chapter.

CAN Bus interface

The Senquip UNI-Z1 is equipped with CAN bus that can be used to read data from all kinds of vehicles and sensors. Many sensors, controllers, and electronic devices can be connected to a single CAN network.

In many cases, the protocol that is being used on the CAN bus is known, and so large volumes of understandable data can be extracted from all kinds of vehicles. Common CAN protocols include:

• J1939, the dominating CAN-based protocol for trucks and busses.

• ISO 11783, a J1939 flavor for agricultural tractors.

• ISO 11992, an interface between trucks and trailers.

• NMEA 2000, a protocol based on J1939 for marine use.

• CANopen, provides a standard for industrial machinery commonly used in industrial automation.

The CAN interface on the UNI-Z1 supports Classical CAN. Pins 3 and 6 provide the CAN interface, with pin 6 being CAN High (dominant high) and pin 3 being CAN Low (dominant low).

Pin	Function
3	CAN1 L
6	CAN1 H

In CAN networks, 120Ω termination resistors are installed at each end of the network. In most installations, the required termination will already be present and the internal termination resistor should remain disabled. If the UNI-Z1 is located at the end of a CAN network and termination is required, the internal termination resistor can be enabled in the CAN settings. No external termination resistor is required.

Warning

In CAN bus systems, the ground supplied to the Senquip UNI-Z1 must be the same ground as used by the CAN network. High differential voltages between the CAN lines and ground can damage the CAN interface.

Specification

Parameter	Specification
CAN physical layer	High-speed CAN (ISO 11898-2 compatible)
Supported protocols	Classical CAN 2.0A and 2.0B
Maximum bit rate	1Mbit/s
Receiver common mode range	+/-30V
Bus fault protection on CAN High and CAN Low	+/-58V
ESD protection, CAN bus pins, contact discharge	+/-8kV
ESD protection, CAN bus pins, air discharge	+/-15kV
Optional termination resistor	120Ω

Settings

Measurements can be scheduled as a multiple of the base-interval. The fastest possible measurement rate is achieved by setting the interval to 1 in which case the CAN network will be sampled on every base interval. To reduce power consumption, the measurement rate can be turned down by increasing the interval.

The CAN bus peripheral on Senquip devices supports can bit rates of 125kbit/s, 250kbit/s, 500kbit/s and 1Mbit/s as specified in the Nominal Baud Rate field.

Configurable internal 120Ω termination resistors can be enabled.

To ensure minimum intrusion on CAN systems, the CAN peripheral can be set to listen only. In this mode the Senquip device will only receive messages that are acknowledged on the bus by a listening node. Where required, the Senquip device can be made to acknowledge messages by selecting the TX Enable option.

The Capture Time setting can be used to set a timeout after which the CAN bus peripheral will stop listening, allowing the Senquip device to transmit received messages and return to sleep. capture-time can also be used as a mechanism to allow the CAN peripheral to sample the CAN bus for a defined time-period.

A full list of CAN bus settings is given in the table at the end of this chapter.

CAN Filters

Most automotive CAN networks transmit hundreds of different messages, each with a unique identifier. The Senquip device allows you to filter and capture only the messages you need using the ID Capture List.

Basic Usage

Enter the CAN IDs you want to capture in hexadecimal, separated by commas. For example:

18FF20F2,18FF36F0,18FF1BF2

During each measurement interval, the device listens for the listed messages until either all are received or the Capture Time expires.

Capturing Multiple Messages

To capture multiple messages with the same ID, use * followed by the number of each message requied:

18FF20F2*4,18FF1BF2*10

This captures:

• 4 messages with ID 18FF20F2

• 10 messages with ID 18FF1BF2

To capture all messages of a certain ID received during the interval, use * without a number:

18FF1F12*

Wildcards and Advanced Filters

• ?? can replace the Priority or Source Address in a J1939 ID.

  For example:

  ??FECA??
  

  This matches any J1939 message with a PGN of FECA, regardless of Priority or Source Address.

• # can be placed at the end of the list to match one of any other message not already listed:

  18FE1451*4,18FE1256*2,#
  

  This captures:

  • 4 messages with ID 18FE1451

  • 2 messages with ID 18FE1256

  • 1 of every other unique ID not already matched

Special Cases

• Leave the list blank to capture one of every message that arrives.

• Use a single * to capture all messages, in the order they arrive.

  Warning

  Capturing all messages may overwhelm the device in high-traffic CAN systems. The number of messages that can be captured in a measurement cycle is internally limited to 128.

Sending CAN Messages

CAN messages can be sent to connected device from within a script. The messages can be sent once, or can be set to repeat at a given time interval. If the device enters sleep or hibernate, repeating messages will be stopped. If the Senquip device is reset, the sending of repeating CAN messages is unaffected. The messages will continue to be sent until a change is applied. For example, if new script is loaded, forcing a reset, the CAN messages will continue to be sent until the new script applies a change. In the case of a malfunction that lasts for more than 30 second, repeating CAN messages will be stopped.

Note

To send CAN messages, the TX Enable option must be selected.

Calibration

Calibration can be applied to each measurement so that the value returned by the Senquip UNI-Z1 is in units that are meaningful in the end application. For instance, a fuel level sensor that outputs a voltage between 0 and 5V may represent a level between 0 and 100 litres of diesel. The voltage measurement can be calibrated to convert from Volts to the more meaningful unit of litres.

In any system, the measurement instrument (the Senquip UNI-Z1), the sensor and possibly the measured value will be subject to errors that may accumulate to reduce accuracy. In a system that measures fluid volume in a 100 litre tank using a 4-20mA sensor, offset errors may result in a non-zero or negative reading when the tank is empty. Sensor gain may also not be perfectly linear and so a 1 litre change may be measured differently when the tank is empty versus when it is full. The sensor may report in inches of liquid height where a more meaningful unit may be litres. To achieve an accurate and meaningful measurement, a calibration can be performed.

In this example, the tank could be calibrated by adding a small amount of liquid, say 10 litres at which point the current measured may be 4.1mA. Now add more liquid to take the level to say 80l. The sensor now reads 16.2mA. The calibration would then be filled into the IO setting as shown below:

Low In	4.1	This is the value in mA measured by the Senquip UNI-Z1
Low Out	10	This is the actual value that we would like to report
High In	16.2	This is the value in mA measured by the Senquip UNI-Z1
High Out	80	This is the actual value that we would like to report
Unit	l	The unit to be reported is litres

Unit Names and Symbols

The calibration Unit field supports plain text together with a number of commonly used engineering symbols. This allows measurements to be displayed using familiar units such as °C, m³, Ω, µS/cm and N·m.

The following characters are supported:

Letters: a-z, A-Z

Numbers: 0-9

Symbols: /, Ω, ·, µ, Δ, ±, ×, :, °, ², ³, ., %, _, -

Examples:

Unit	Description
V	Volts
A	Amps
°C	Degrees Celsius
°F	Degrees Fahrenheit
Ω	Ohms
kΩ	Kilohms
m³	Cubic metres
m²	Square metres
µS/cm	Microsiemens per centimetre
N·m	Newton metres
kg/m³	Density
%RH	Relative humidity
L/min	Litres per minute

When entering units on Windows, some special characters can be entered using their ALT codes on the numeric keypad.

Character	Windows ALT Code
°	ALT+0176
²	ALT+0178
³	ALT+0179
µ	ALT+0181
±	ALT+0177
×	ALT+0215

The remaining symbols can be copied directly from this guide or inserted using the Windows Character Map (charmap.exe) or the Windows Emoji & Symbols panel(Win + .).

Character	Description
Ω	Ohm
Δ	Uppercase Delta
·	Middle dot

Warnings and Alarms

For each measurement type, high and low warning and alarm levels can be set. Once enabled, each time a measurement is completed, the returned value will be compared with low and high warning and alarm thresholds. If a warning or alarm level is breached, a message will immediately be transmitted. As long as the warning or alarm condition persists, messages will be transmitted at the exception-interval rather than the transmit-interval.

Note

If calibration has been applied, then the warning and enable thresholds should be set in the calibrated units.

To set a high level warning or alarm level only, set the low level to a value that is impossible to achieve. For instance to set a high only warning at 50V, set the low warning to -1V which is an unachievable value.

Hysteresis can be specified in increments of the specified unit, to prevent multiple alarms in the presence of electrical noise.

Hysteresis

External Sensor Settings

A full list of settings for external sensors is given in the table below.

Name	Item	Function	Range	Unit	Internal Reference
Input 1
Name	text	A name for the input that is meaningful to the user.	25 chars		input1.name
Interval	integer	The number of base intervals after which the input is sampled. A value of 1 means that the input is collected every base interval. Set to 0 to disable.	0 to 10000		input1.interval
Mode	preset	Specifies the function of the IN1 terminal. The calibration, warnings and alarms are applied to this mode.			input1.mode
Digital 1
Digital Threshold	decimal	A threshold against which the input is compared to determine if the input state is ON or OFF.	0 to 30	Volts	input1.digital.threshold
Digital Hysteresis	decimal	Once the input is in a certain state, hysteresis is the amount by which the input has to change before moving to the other state.	0 to 20	Volts	input1.digital.hysteresis
Count Hours	boolean	Counts the number of hours the digtial input is ON (above threshold).			input1.digital.count_hours
Digital Change Alert	boolean	Sets whether a change in digital state generates an alert.			input1.digital.alert.enable
Analog 1 Calibration	text	Calibration parameters for Analog 1. Refer to user guide.	30 chars		input1.cal
Unit	text	The unit of measure associated with the calibration. Examples: Litres/min, RPM, Volts			input1.unit
Warning	text	Warning thresholds. Refer to user guide.			input1.warning
Alarm	text	Alarm thresholds. Refer to user guide.			input1.alarm
Alarm/Warning Hysteresis	decimal	Once the input is in a certain state, hysteresis is the amount by which the input has to change before moving to the other state.			input1.hysteresis
Pulse Input
Pulse Counting	boolean	Enables counting of pulses in addition to frequency measurement.			input1.pulse.enable
Reset Value	integer	The value at which the number of pulses counted on the input is reset to zero.	1 to 2000000000	Counts	input1.pulse.reset_value
Pulse Scaling	decimal	Multiplier to convert the pulse count to a useful unit.			input1.pulse.scaling
Pulse Unit	text	The unit of measure associated with the scaled pulse count. Eg: Litres			input1.pulse.unit
Pulse Warning	text	Warning thresholds. Refer to user guide.			input1.pulse.warning
Pulse Alarm	text	Alarm thresholds. Refer to user guide.			input1.pulse.alarm
Input 2
Name	text	A name for the input that is meaningful to the user.	25 chars		input2.name
Interval	integer	The number of base intervals after which the input is sampled. A value of 1 means that the input is collected every base interval. Set to 0 to disable.	0 to 10000		input2.interval
Mode	preset	Specifies the function of the IN2 terminal. The calibration, warnings and alarms are applied to this mode.			input2.mode
Digital 2
Digital Threshold	decimal	A threshold against which the input is compared to determine if the input state is ON or OFF.	0 to 30	Volts	input2.digital.threshold
Digital Hysteresis	decimal	Once the input is in a certain state, hysteresis is the amount by which the input has to change before moving to the other state.	0 to 20	Volts	input2.digital.hysteresis
Count Hours	boolean	Counts the number of hours the digtial input is ON (above threshold).			input2.digital.count_hours
Digital Change Alert	boolean	Sets whether a change in digital state generates an alert.			input2.digital.alert.enable
Analog 2 Calibration	text	Calibration parameters for Analog 2. Refer to user guide.	30 chars		input2.cal
Unit	text	The unit of measure associated with the calibration. Examples: Litres/min, RPM, Volts			input2.unit
Warning	text	Warning thresholds. Refer to user guide.			input2.warning
Alarm	text	Alarm thresholds. Refer to user guide.			input2.alarm
Alarm/Warning Hysteresis	decimal	Once the input is in a certain state, hysteresis is the amount by which the input has to change before moving to the other state.			input2.hysteresis
Output 1
Name	text	A name for the input that is meaningful to the user.	25 chars		output1.name
Interval	integer	Does not affect output mode. The number of base intervals at which the input is sampled. Set to 0 to disable. Set to 1 for every base interval.	0 to 10000		output1.interval
Mode	preset	Specifies the function of the OUT1 terminal.			output1.mode
Warnings	boolean	Determines if the output is turned on when a warning is active.			output1.warnings
Alarms	boolean	Determines if the output is turned on when an alarm is active.			output1.alarms
Alerts	boolean	Determines if the output is turned on when an alert is active.			output1.alerts
Hold Time	integer	Sets the time in seconds for which the output is held on after it is triggered. If set to zero, the output remains on while any exceptions are active.		Seconds	output1.hold_time
Digital Change Alert	boolean	If enabled, a change in digital state will generate an alert.			output1.digital.alert.enable
Analog 3 Calibration	text	Calibration parameters for Analog 3. Refer to user guide.	30 chars		output1.cal
Unit	text	The unit of measure associated with the calibration. Examples: Litres/min, RPM, Volts			output1.unit
Warning	text	Warning thresholds. Refer to user guide.			output1.warning
Alarm	text	Alarm thresholds. Refer to user guide.			output1.alarm
Alarm/Warning Hysteresis	decimal	Once the input is in a certain state, hysteresis is the amount by which the input has to change before moving to the other state.			output1.hysteresis
Thermocouple 1
Name	text	A name for the input that is meaningful to the user.	25 chars		tc1.name
Interval	integer	The number of base intervals after which the thermocouple is measured and events are checked. A value of 1 means that the input is collected every base interval. Set to 0 to disable.	0 to 10000		tc1.interval
Hysteresis	decimal	The amount by which the measured value has to drop below the threshold to re-enable the event.	-1000 to 1000	°C	tc1.hysteresis
Type	text	Determines the type of thermocouple connected. Valid values are: K, J, T, N, S, E, B and R	1 chars		tc1.type
Warning	text	Warning thresholds. Refer to user guide.	-1000 to 1000	°C	tc1.warning
Alarm	text	Alarm thresholds. Refer to user guide.	-1000 to 1000	°C	tc1.alarm
CAN 1
Name	text	A name that is meaningful to the user.	25 chars		can1.name
Interval	integer	The number of base intervals after which the CAN module is turned on. Set to 0 to disable.	0 to 10000		can1.interval
Nominal Baud Rate	integer	Baud rate for CAN communication. Supported values are: 125, 250, 500, 1000		kbit/s	can1.nominal_baud
Capture Time	integer	The device will capture matching messages for this length of time.		Seconds	can1.capture_time
TX Enable	boolean	Allows the device to transmit and acknowledge messages on the CAN bus.			can1.tx_enable
ID Capture List	text	List of IDs to be captured in HEX format, separated by a comma eg: 18FEE60A. Leave blank to capture all.	200 chars		can1.id_list
Send Raw Data	boolean	If ticked, all captured messages will be added to the data message.
CAN 2			25 chars		can2.name
Name	text	A name that is meaningful to the user.	0 to 10000		can2.interval
Interval	integer	The number of base intervals after which the CAN module is turned on. Set to 0 to disable.		kbit/s	can2.nominal_baud
Nominal Baud Rate	integer	Baud rate for CAN communication. Supported values are: 125, 250, 500, 1000		Seconds	can2.capture_time
Capture Time	integer	The device will capture matching messages for this length of time.			can2.tx_enable
TX Enable	boolean	Allows the device to transmit and acknowledge messages on the CAN bus.	200 chars		can2.id_list
ID Capture List	text	List of IDs to be captured in HEX format, separated by a comma eg: 18FEE60A. Leave blank to capture all.
Send Raw Data	boolean	If ticked, all captured messages will be added to the data message.
Current Loop 1			25 chars		current1.name
Name	text	A name for the input that is meaningful to the user.	0 to 10000		current1.interval
Interval	integer	The number of base intervals after which the input is sampled. A value of 1 means that the input is collected every base interval. Set to 0 to disable.			current1.mode
Mode	preset	Specifies the function of the SRC1 terminal.			current1.always_on
Always On	boolean	Determines if Switched Power is to be enabled permanently.	0 to 3600	Seconds	current1.start_time
Start Time	decimal	Time in seconds that the output is turned on before measurements are taken. Allows an external device to stabilise.			current1.digital.alert.enable
Digital Change Alert	boolean	Sets whether a change in digital state generates an alert. (Digital Mode Only)	30 chars		current1.cal
Current 1 Calibration	text	Calibration parameters for Current 1. Refer to user guide.			current1.unit
Unit	text	The unit of measure associated with the calibration. Examples: Percent, Pascals, Meters			current1.warning
Warning	text	Warning thresholds. Refer to user guide.			current1.alarm
Alarm	text	Alarm thresholds. Refer to user guide.			current1.hysteresis
Alarm/Warning Hysteresis	decimal	The amount by which the calibrated current value has to drop below the threshold to re-enable the event.
Current Loop 2			25 chars		current2.name
Name	text	A name for the input that is meaningful to the user.	0 to 10000		current2.interval
Interval	integer	The number of base intervals after which the input is sampled. A value of 1 means that the input is collected every base interval. Set to 0 to disable.			current2.mode
Mode	preset	Specifies the function of the SRC2 terminal.			current2.always_on
Always On	boolean	Determines if Switched Power is to be enabled permanently.	0 to 3600	Seconds	current2.start_time
Start Time	decimal	Time in seconds that the output is turned on before measurements are taken. Allows an external device to stabilise.			current2.digital.alert.enable
Digital Change Alert	boolean	Sets whether a change in digital state generates an alert. (Digital Mode Only)	30 chars		current2.cal
Current 2 Calibration	text	Calibration parameters for Current 2. Refer to user guide.			current2.unit
Unit	text	The unit of measure associated with the calibration. Examples: Percent, Pascals, Meters			current2.warning
Warning	text	Warning thresholds. Refer to user guide.			current2.alarm
Alarm	text	Alarm thresholds. Refer to user guide.			current2.hysteresis
Alarm/Warning Hysteresis	decimal	The amount by which the calibrated current value has to drop below the threshold to re-enable the event.
Serial 1			25 chars		serial1.name
Name	text	A name for the input that is meaningful to the user.	0 to 10000		serial1.interval
Interval	integer	The number of base intervals after which the serial port is turned on. Set to 0 to disable.			serial1.type
Type	preset	The electrical interface type.			serial1.termination
Termination Resistor	boolean	This parameter enables the integrated termination resistor.			serial1.mode
Mode	preset	Describes how the serial port is to be handled. CAPTURE: serial data is captured between start and end characters. MODBUS: serial data is treated according to MODBUS RTU standard			serial1.baud
Baud Rate	integer	Baud rate for serial communication. Common values are: 4800, 9600, 19200, 38400, 57600, 115200			serial1.settings
Settings	text	A string describing the number of bytes: 7,8,9. Parity type: N(none), E(even), O(odd). Number of stop bits: 1 or 2. Typically: 8N1
Capture			32 chars		serial1.capture.start
Start String	text	The serial port starts reading data when it detects these characters. Example: $GPGGA, serial data will be ignored until $GPGGA is received after which data will be captured. If nothing is specified, the serial port will capture all data until the timeout period is reached.	0 to 60000	Milliseconds	serial1.capture.start_idle_time
Idle Time Before Start	integer	For a valid start condition, there must be this amount of idle time before receiving serial data. Additionally, the captured data will restarted if the serial port is idle for this time. Set to 0 to disable.	32 chars		serial1.capture.end
End String	text	Once capturing, if these characters are received, the serial port will stop capturing and will return to sleep. For binary data or escape sequences refer to the User Guide.	32 chars		serial1.capture.request
Request String	text	This string will be sent when the serial port is first turned on. Use this function to request data from a remote module.		Seconds	serial1.capture.maxtime
Max Time	integer	The device will wait this length of time for a valid capture.			serial1.capture.maxchars
Max Chars	integer	Maximum number of characters to be captured before the serial port goes back to sleep.			serial1.capture.alert
Alert on Capture	boolean	If checked an alert will be raised on any successful serial capture.
MODBUS RTU			0 to 10	Seconds	serial1.modbus.timeout
Slave Timeout	decimal	How long to wait for a response from each slave device.
MODBUS 1			25 chars		mod1.name
Modbus 1 Name	text	A meaningful name for Modbus Channel 1.	18 chars		mod1.settings
Modbus 1 Settings	text	Settings for Modbus Channel 1. Refer to user guide.	30 chars		mod1.cal
Modbus 1 Calibration	text	Calibration paramters for Modbus Channel 1. Refer to user guide.			mod1.unit
Modbus 1 Unit	text	The unit of measure associated with the calibration. Examples: Percent, L/hr, Meters			mod1.warning
Warning	text	Warning thresholds. Refer to user guide.			mod1.alarm
Alarm	text	Alarm thresholds. Refer to user guide.
MODBUS 2			25 chars		mod2.name
Modbus 2 Name	text	A meaningful name for Modbus Channel 2.	18 chars		mod2.settings
Modbus 2 Settings	text	Settings for Modbus Channel 2. Refer to user guide.	30 chars		mod2.cal
Modbus 2 Calibration	text	Calibration paramters for Modbus Channel 2. Refer to user guide.			mod2.unit
Modbus 2 Unit	text	The unit of measure associated with the calibration. Examples: Percent, L/hr, Meters			mod2.warning
Warning	text	Warning thresholds. Refer to user guide.			mod2.alarm
Alarm	text	Alarm thresholds. Refer to user guide.
MODBUS 3			25 chars		mod3.name
Modbus 3 Name	text	A meaningful name for Modbus Channel 3.	18 chars		mod3.settings
Modbus 3 Settings	text	Settings for Modbus Channel 3. Refer to user guide.	30 chars		mod3.cal
Modbus 3 Calibration	text	Calibration paramters for Modbus Channel 3. Refer to user guide.			mod3.unit
Modbus 3 Unit	text	The unit of measure associated with the calibration. Examples: Percent, L/hr, Meters			mod3.warning
Warning	text	Warning thresholds. Refer to user guide.			mod3.alarm
Alarm	text	Alarm thresholds. Refer to user guide.
MODBUS 4			25 chars		mod4.name
Modbus 4 Name	text	A meaningful name for Modbus Channel 4.	18 chars		mod4.settings
Modbus 4 Settings	text	Settings for Modbus Channel 4. Refer to user guide.	30 chars		mod4.cal
Modbus 4 Calibration	text	Calibration paramters for Modbus Channel 4. Refer to user guide.			mod4.unit
Modbus 4 Unit	text	The unit of measure associated with the calibration. Examples: Percent, L/hr, Meters			mod4.warning
Warning	text	Warning thresholds. Refer to user guide.			mod4.alarm
Alarm	text	Alarm thresholds. Refer to user guide.
MODBUS 5			25 chars		mod5.name
Modbus 5 Name	text	A meaningful name for Modbus Channel 5.	18 chars		mod5.settings
Modbus 5 Settings	text	Settings for Modbus Channel 5. Refer to user guide.	30 chars		mod5.cal
Modbus 5 Calibration	text	Calibration paramters for Modbus Channel 5. Refer to user guide.			mod5.unit
Modbus 5 Unit	text	The unit of measure associated with the calibration. Examples: Percent, L/hr, Meters			mod5.warning
Warning	text	Warning thresholds. Refer to user guide.			mod5.alarm
Alarm	text	Alarm thresholds. Refer to user guide.
MODBUS 6			18 chars		mod6.settings
Modbus 6 Settings	text	Settings for Modbus Channel 6. Refer to user guide.	30 chars		mod6.cal
Modbus 6 Calibration	text	Calibration paramters for Modbus Channel 6. Refer to user guide.
MODBUS 7			18 chars		mod7.settings
Modbus 7 Settings	text	Settings for Modbus Channel 7. Refer to user guide.	30 chars		mod7.cal
Modbus 7 Calibration	text	Calibration paramters for Modbus Channel 7. Refer to user guide.
MODBUS 8			18 chars		mod8.settings
Modbus 8 Settings	text	Settings for Modbus Channel 8. Refer to user guide.	30 chars		mod8.cal
Modbus 8 Calibration	text	Calibration paramters for Modbus Channel 8. Refer to user guide.
MODBUS 9			18 chars		mod9.settings
Modbus 9 Settings	text	Settings for Modbus Channel 9. Refer to user guide.	30 chars		mod9.cal
Modbus 9 Calibration	text	Calibration paramters for Modbus Channel 9. Refer to user guide.
MODBUS 10			18 chars		mod10.settings
Modbus 10 Settings	text	Settings for Modbus Channel 10. Refer to user guide.	30 chars		mod10.cal
Modbus 10 Calibration	text	Calibration paramters for Modbus Channel 10. Refer to user guide.