Modbus measurement channels

Configuration section to configure the settings for the 20 modbus measurement channels. The basic settings are configured in the "Basic" tab. The "Configuration" tab is used to determine from which modbus registers the data is received and how the data stored in the modbus registers is to be interpreted. The "Scale" tab allows for the read out raw data to be resecaled into the desired unit. The "Alarms" tab is used to set the alarm thresholds and the "Trigger" tab to determine the trigger thresholds as well as the actions to be performed in case the trigger conditions are met.

Basic

"Modbus measurement channels" configuration section, "Basic" tab

1	freely selectable channel designation for the modbus measurement channels
2	Basic settings for the modbus measurement channel
	off	Measurement channel deactivated
	Modbus	The data for the measurement channel are determined usint the RS485 interface selected in the configuration section "Modbus interface". The interface is always configured as modbus client (formerly master) in "RTU" operating mode.
3	defines how the modbus measurement channel is to be handled by the report elements of the server
	digital	Digital measurement value. I.e. the system considers each measurement value independently from the measured values before or after.
	analogue	Analogue measurement value. I.e. the system considers each measurement value independently from the measured values before or after.
	Cnt.Day	Day counter. This means that the system anticipates that the measurement value of the channel will continuously increase and is reset once per day.
	Cnt.Intervl	Interval counter. This means that the system assumes that the counter reading is reset each time a measurement is recorded.
4	String that is used as a measurement unit by all of the server display elements [0‑16 8 characters]
5	Number of decimal places that are used by all of the server display elements

Configuration

"Modbus measurement channels" configuration section, "Configuration" tab

1	Address of the modbus server
2	Address of the register that should be read
3	Format in which the data to be read is stored in the register
	Digital	A digital value should be read.
	Signed	A signed integer value should be read.
	Unsigned	The integer value to be read is not signed.
	Float	A 32-bit float should be read.
4	Selection of the word length (i.e. number of bits the integer value consists of) Only available if "Signed" or "Unsigned" has been selected for the format (i.e. an integer value should be read from the register)
	16	16-bit integer
	32	32-bit integer. Two registers must be read from the modbus server for this purpose.
5	Selection of the word order, if the selection of format and word length requires that 2 registers are read from the modbus server (i.e. "Float", "Signed" with a word length of 32 bit or "Unsigned" with a word length of 32 bit has been selected)
	HI-LO	HI word on the lower register address and the LO word on the higher register address
	LO-HI	LO word on the lower register address and the HI word on the higher register address
6	Function code to be used for accessing the register
	FC01	Read Coils
	FC02	Read Discrete Inputs
	FC03	Read Holding Registers
	FC04	Read Input Registers

Scale

"Modbus measurement channels" configuration section, "Scale" tab

1	Selection if the raw data read from the register is to be rescaled before further processing.
	off	The data is processed unchanged..
	on	Scale active (i.e. the data is rescaled into the desired unit before further processing)
2	Start of the measurement range in the unit of the modbus server (i.e. raw value to be read from the modbus server)
3	End of the measurement range in the unit of the modbus server (i.e. raw value to be read from the modbus server)
4	Start of the measurement range in the measurement unit
5	Start of the measurement range in the measurement unit
6	Procedure in the event of measurement range violations
	Ignore	The measurement value is calculated beyond the range limits.
	Silent cutoff	The measurement value is truncated at the range limits.

Tip: Calculation of the measurement values when scale is active:

0 %	4 mA	D
100 %	20 mA	C
0 % Modbus	0	A
100 % Modbus	65535	B

Measurement value in the unit of the modbus server	32767	E
Scaled measurement value	11,9998 mA	F

F = ( (C - D)/(B - A) ) * (E - A) + D

F = ( (20 mA - 4 mA) /(65535 - 0) ) * (32767 - 0) + 4 mA =11,9998 mA

Alarms

Note: In the event of a warning or an alarm, an entry is always created in the alarm list and an immediate transmission is initiated. If the warning or the alarm is cancelled again, an immediate transmission follows.

"Modbus measuement channels" configuration section, "Alarms" tab

Which of the configuration parameters are available for the respective modbus measurement channel depends on the format selected via the "Configuration" tab in which the data to be read is saved in the register.

Format "Digital"
1	A "high" at the universal input triggers a "warning".
2	A "high" at the universal input triggers an "alarm".

All other formats
3	A warning is triggered, if the measurement value drops to or below this value.
4	A warning is triggered, if the measurement value meets or exceeds this value.
5	An alarm is triggered, if the measurement value drops to or below this value.
6	An alarm is triggered, if the measurement value meets or exceeds this value.
7	Hysteresis for all-clear in event of alarm/warning (e.g. Hyst=5 %, alarm or warning at 100 -> all-clear at 95)

Trigger

There are two different types of triggers:

Event trigger (RI, XM)
The relevant operation (e.g. initiate transmission) is only executed once when the trigger event occurs.
Level trigger (ON, QX)
The relevant operation (e.g. use alternative record interval) is executed as long as the trigger is active.

"Modbus measurement channels" configuration section, "Trigger" tab

	Event trigger:
1	Execute recording immediately
2	Initiate transmission
	Level trigger:
3	Activate online mode
4	The alternative record interval should be used.
5	The alternative transmission cycle should be used.

Format "Digital"
9	Event trigger: Selection of the edge at which the trigger should be initiated Level trigger: not relevant. The trigger is active as long as the measurement value is "High".
	rising	The rising edge initiates the trigger.
	falling	The falling edge initiates the trigger.
	both	Both edges initiate the trigger.

All other formats
10	Selection if the corresponding action is to be performed upon exceeding or falling below the value entered in the "level" field
	greater or equal	Event trigger: The trigger is initiated if the measurement value meets or exceeds this value. Level trigger: The trigger is active as long as the measurement value is higher than the level or equal to the level.
	less or equal	Event trigger: The trigger is initiated if the measurement value drops to or falls below this value. Levelt rigger: The trigger is active as long as the measurement value is lower than the level or equal to the level.
11	Levels for initiating the trigger. The hysteresis is used to determine the level to reset the trigger.
12	Hysteresis for revoking the trigger (e.g. hyst=5 %, level = greater or equal, trigger at 100 -> all-clear at 95)