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2) Locating the command registers
The command registers may be located in any valid D-type register within the PLC. A
contiguous block of 7 registers is required. The modem will need to know the start
address of this block and this is done with the command:
AT%ADR =
xxxxxx
Where xxxxxx is the address from 1 to 6 digits.
Example 3-4
Command Block Address setting
AT%ADR = 1000
Defines the command block at D1000
AT%ADR = 20
Defines a command block at D20
Also, the command block need not be within the same PLC connected to the modem.
It may be in another PLC connected over a local network. The PLC network number
may be defined using the command:
AT%ADN = FF
FF is the default setting.
3) Starting the poll
Polling is started by the command:
AT%ADO = 1
And stopped by the command:
AT%ADO = 0
Polling will start approximately 10 seconds after the next modem reset.
If the modem does not receive a response to its poll request, polling will be
temporarily suspended until the next reset.
If the modem is still connected to a PC terminal when it starts to poll, then you should
see a formatted read request string appear. If you are able to interpret such strings,
this can be used as a useful tool to check your settings are correct.
3.5.2 Online Configuration
Any of the parameters listed in the whole of section 3 may be modified in a remote
modem by calling it and entering the Administrator Access Code. For a full
explanation of how to do this see section 3.4.1 3).
