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WE2107 - Communication commands
I1820-1.3 en HBM
4.5 Determining bus occupation (Bus Scan)
It is often useful, each time the bus is enabled or if WE responses are missing, to determine
the bus configuration. Use Bus Scan to determine bus address occupation. The prerequisite
here is for all the modules to be set to the same baud rate. Carry out the bus scan as follows:
1. Initialize the master interface with the set WE baud rate
2. Scan an address with the following command sequence:
;S00; Select address
ADR?; Query address
The WE addressed by this address responds with an 00LF If there is no response after
about 100ms, there is no WE at this address. If the master receives undefined characters
or does nor receive an ?‐character, there may be a bus malfunction or multiple address
occupation. The bus master must respond accordingly.
3. Repeat Number 2 with the following addresses 01...31.
If there are only a few WEs connected with known addresses, the bus scan can naturally
relate to these addresses only. If all the WEs are successfully established as bus users, the
WE identification string may be read in (identification = production number).
The time‐out setting for the master interface driver is crucial for the speed of the bus scan.
The select command needs a maximum 20ms to output at 9600 baud. The WE does not
respond to this select command.
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