The transmitter and the connected probes are treated as separate Modbus slaves, each with their own fixed unit identifier (unit ID) value. The unit ID in the Modbus request defines the intended recipient of the request (transmitter or probe).
|Transmitter with barometer module||240|
|Probe connected to probe 1 connection terminal||241|
|Probe connected to probe 2 connection terminal||242|
The unit IDs of the connected probes identify the probes based on the probe connection terminal that they are connected to. The probes use these unit IDs (241 and 242) only when they are connected to the transmitter. When the probes are accessed directly without the transmitter, the probes have their own Modbus address settings instead of these unit IDs.
If the probe fails to respond to the request, the transmitter responds to the client with the exception code Gateway Target Device Failed to Respond.
|For probe-specific register information, see the connected probe's Modbus documentation.|