Yokogawa GC1000 Mark II Process Gas Chromatograph - Manual (Page 71)

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<5. Actions of External Input and Output Signals >
IM 11B03A03-01E
5.4.5 MODBUS Communication Data Specification
(1) Coil (Command Contact)
(1) Run command
Commands the start of continuous analysis to the GC1000 Mark II.
(2) Stop command
Commands the stop of continuous analysis to the GC1000 Mark II.
(3) Time setting request
Requests the GC1000 Mark II to set the device clock to values in addresses 40001-
40004. Before this request, time should be set by a holding register.
(4) Stream Sequence setting command
Commands the GC1000 Mark II to perform the specified stream sequence. This
command is rejected if the measurement status is in Calibration/Validation, including
wait status, or in Stream (1 cycle), including wait status.
(5) Calibration/Validation command
Commands the GC1000 Mark II to perform the specified calibration or validation.
Corresponding numbers to the Calibration/Validation numbers to be specified are as
follows:
Calibration 1 to 3: 1 to 3
Validation 1 to 3: 4 to 6
This command is rejected if the measurement status is in Stream (1 cycle), including
wait status, or the calibration method is set to Automatic/Manual.
(6) Stream (continuous) setting command
Commands the GC1000 Mark II to perform a continuous measurement of the speci-
fied stream. This command is rejected if the measurement status is in Calibration/
Validation, including wait status, or in Stream (1 cycle), including wait status.
Note 1: Coils are automatically reset from 1 to 0 when the slave accepts the message.
Note 2: Pattern requests are queued when received but may not activate immediately.
Note 3: Input relays should be monitored to determine when commands actually activate.
Note 4: When the master sends multiple commands to the slave simultaneously, the slave executes it in the order received
regardless of the content of the commands.
3rd Edition : Aug. 23. 2006-00