Allen Bradley Communication Problem

[rajsiyer 7]

Hi to all I am new to this forum,I am facing some problem in communication of PLC network. I am looking forward for your help My scheme is as follows(attached) I am able to communicate with 7 no. of PLC's but only one is not communicating(one incircled in RED) I am able to communicate Node no-1 and node no.-3 too,which are connected to Node no-2 via looping.(i had cross checked the Node Nos.) For communication(DH 485 Bus) I am using DF1 (i.e. RS 232 converted to DH 485 in Communication configuration on COM Port 1) using Net AIC 1761 and CP3 cable(because My DH485 port is connected to some other network). I had tried all the possible and suggested solutions for this. One thing remain is to change the CPU of PLC(some one suspects might faulty ports) Please help me out to solve this problem. nitin mrplc.doc

[jstolaruk 9]

did you try swapping the NET-AIC with a known working node to verify its working? Edited 28 Feb 2006 by jstolaruk

[Philip Wilkie 0]

The scheme you have pictured should work. In order to help you we need more information about what is happening: 1. What are the Ch0 and Ch1 Comms LED's doing on the processor that is not communicating? 2. What are the LED's doing on the NET_AIC+? 3. Is that NET-AIC+ powered on? 4. Are you certain that every address node on each network is unique? 5. Are they all set for the same baud rate? 6. What is the "Max Address" setting for all the PLC's and drivers? 7. Have you swapped all the cables and parts one at a time to ensure there is not a hardware fault?

[nitinkakade 0]

Thanks Philip, How z things there. Nice to see your reply,not able to prompt reply sorry for this, The Ch0 and Ch1 Comms LED's doing on the processor that is not communicating are showing indication in green i.e. it is working ok. All the LED's on the NET_AIC+ are Blinking in green and also power is given(their power switch is ON the Exernal power ) All are set for the same Baud rate. All the node has a unique address(Node no.1 to Node no 9 ). The "Max Address" setting for all the PLC's and drivers is 9. Have you swapped all the cables and parts one at a time to ensure there is not a hardware fault? yaa i have chnaged all the cable and parts one by one just remain is to change the CPU. Anticipating your reply