Siemens Milltronics SF 500 - Error Handling

Page 90 Milltronics SF 500 - INSTRUCTION MANUAL 7ML19985CN01
mmmmm
Communications
Slave
Modem
• auto answer on (dip switch)
• load factory default (dip switch)
• no flow control (dip switch)
• baud rate = 9600
• 10 data bits (probably the default)
SF 500
• set P770, port 1, to the value 3 (Modbus RTU)
• set P771, port 1, to the value 1 (Network ID 1)
• set P772, port 1, to the value 3 (Baud rate of 9600)
• set P773, port 1, to the value 0 (No Parity)
• set P774, port 1, to the value 8 (8 Data Bits)
• set P775, port 1, to the value 1 (1 Stop Bit)
• set P778, port 1, to the value 1 (Communications through Modem)
• set P779, port 1, to the value 300 (Modem Inactivity of 300 seconds)
Error Handling
Modbus Responses
When polled by a Modbus Master, a slave device will do one of the following:
1. Not reply.
This means that something went wrong with the transmission of the message.
2. Echo back the command with the correct response.
This is the normal response. (see the Modbus specifications for more details).
3. Return an Exception Code.
This reflects an error in the message.
Note: Parameters are defined in the Installation section (page 6).