Hi guys,
I have a Siemens CP341-RS422/485 module and I am trying to establish MODBUS communication to a series of Multilin269 / 469 protection relays.
To keep things simple, as the moment I am simply trying to connect to one Multilin269+. I receive the error message 0x8030, which indicates I am getting no reply from the Modbus slave.
Could someone please tell me the correct way to wire the D-Sub-15 Plug from the CP341 to the Multilin?
I believe this is where the problem lies as I have checked that the Modbus parameters match, the slave address exists and the reply monitoring time is 2s, which should be more than enough for a simple 'Read Actual Values' Modbus command.
The Multilin has 3 terminals for RS-485: 46(-), 47(+) and 88 (shield). Do I simply connect Pin 4 R(A)- to terminal 46 and Pin 11 R(B)+ to terminal 47? What about pins 2 and 11 on the CP341? And pin8 (ground)?
I have tried swapping the the pins 4 and 11 but still no luck.
The code 'appears' to be working - I get a brief flash on the Tx LED every 2 seconds, which is the PtP reply timeout configured in the CP-341. The Modbus message appears to be constructed correctly. I have actually used the same message to communicate with a SEPAM80, but from a CP-441-2.
Any help would be greatly appreciated.
Regards,
Anton
I have a Siemens CP341-RS422/485 module and I am trying to establish MODBUS communication to a series of Multilin269 / 469 protection relays.
To keep things simple, as the moment I am simply trying to connect to one Multilin269+. I receive the error message 0x8030, which indicates I am getting no reply from the Modbus slave.
Could someone please tell me the correct way to wire the D-Sub-15 Plug from the CP341 to the Multilin?
I believe this is where the problem lies as I have checked that the Modbus parameters match, the slave address exists and the reply monitoring time is 2s, which should be more than enough for a simple 'Read Actual Values' Modbus command.
The Multilin has 3 terminals for RS-485: 46(-), 47(+) and 88 (shield). Do I simply connect Pin 4 R(A)- to terminal 46 and Pin 11 R(B)+ to terminal 47? What about pins 2 and 11 on the CP341? And pin8 (ground)?
I have tried swapping the the pins 4 and 11 but still no luck.
The code 'appears' to be working - I get a brief flash on the Tx LED every 2 seconds, which is the PtP reply timeout configured in the CP-341. The Modbus message appears to be constructed correctly. I have actually used the same message to communicate with a SEPAM80, but from a CP-441-2.
Any help would be greatly appreciated.
Regards,
Anton
