3. MODBUS Protocol
IM 249x-COMM
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If there is a communication error, such as parity, LRC or CRC the Power Series
Plus will not respond. If there is no communication error, but the device cannot
handle the query for some reason, it will return one of the following exception
codes:
01 –
Illegal Function
The function code received in the query is not an allowable action for the
slave.
02 – Illegal Data Address
The data address received in the query is not an allowable address for the
slave.
03 – Illegal Data Value
A value contained in the query data field is not an allowable value for the
slave.
09 – EEPROM Write Error
Data was not correctly saved to EEPROM. If there is a power outage, the
unit will not save the changes made. Contact your distributor.
The network address, baud rate, transmission mode and parity setting can only
be changed using the front panel interface.
To get to the setting mode press the keys in the following order –
Mode - Mode – Set.
The display will now be showing the PT ratio ‘Pt’ or the CT ratio ‘Ct’. Now press
Next repeatedly until you see ‘Addr’ in the top display. The middle display will be
showing the current address of the unit. To change it, press Set. The first digit
will start blinking. Press Inc to increment the first digit, or press Next to move to
the second digit. When you are finished changing the value, press Set. Both
digits will begin blinking. Press Set once again to save the value in EEPROM
and move on the next settings. Pressing Mode at any time will back you out of
the process.
Now the top display will show ‘Sci’ – Serial Comm Interface. The middle display
will show three values – the baud rate, the transmission mode and the parity,
separated by dots. The default looks like – ’96.r.n’, meaning 9600 bps, RTU
mode, no parity. To change a setting press Set. The baud rate will start to blink.
