thedolanduck
Member
Hello everyone! Posting from Argentina as I don't know what else to do.
For a bit of context, I am using an Allen-Bradley Micro850 PLC and five Schneider Altivar 312 VFD for a client at my current job. My client wants me to communicate these devices over Modbus RTU.
To connect them all, I am using this Modbus splitter from Schneider, as I have used it in the past. All ATV312 use an RJ45 connection, so that was easy. The tricky part is the PLC, which uses a Mini DIN connection. So, I looked up its pin-out in the PLC's manual (see page 56) and the corresponding Modbus pin-out for the RJ45 connector in the VFD's Modbus manual, and then manufactured a cable: standard RJ45 T568B in one end, and Mini DIN on the other, with the appropriate pins attached respectively.
Then, I set up the PLC as master using 19.2kbps, 8E1 and RS-485. Set up one of the VFDs the same way, and made a quick program in Connected Components Workbench using the MSG_MODBUS function to read the first VFD's Status Word:
Long story short: it doesn't work It keeps throwing error 55 which, according to CCW's help, means:
Thank you very much for your time, and I really hope someone is able to help me, as I don't know what else to do.
P.S: Yes, I tried point to point connection with just the one VFD, same results.
P.S.S: I also was able to connect the ATV312 through Modbus to my laptop, using an USB-to-RS485 converter, and using the software SoMove. This means the Modbus connection of the VFD is working.
I could not, however, connect the PLC through Modbus (I programmed it through USB) with the CCW software.
For a bit of context, I am using an Allen-Bradley Micro850 PLC and five Schneider Altivar 312 VFD for a client at my current job. My client wants me to communicate these devices over Modbus RTU.
To connect them all, I am using this Modbus splitter from Schneider, as I have used it in the past. All ATV312 use an RJ45 connection, so that was easy. The tricky part is the PLC, which uses a Mini DIN connection. So, I looked up its pin-out in the PLC's manual (see page 56) and the corresponding Modbus pin-out for the RJ45 connector in the VFD's Modbus manual, and then manufactured a cable: standard RJ45 T568B in one end, and Mini DIN on the other, with the appropriate pins attached respectively.
Then, I set up the PLC as master using 19.2kbps, 8E1 and RS-485. Set up one of the VFDs the same way, and made a quick program in Connected Components Workbench using the MSG_MODBUS function to read the first VFD's Status Word:
Code:
Modbus Local Parameters:
Channel = 2 // Embedded Serial Port
TriggerType = 1 // So it keeps sending messages while IN = TRUE
Cmd = 3 // Read N registers
ElementNo = 1 // Just 1 register
Modbus Target Parameters:
Address = 3201 // Parameter address of the VFD's Status Word
Node = 1 // Modbus address of one VFD
My main concern is the cable. I triple checked, pin-out is alright, but maybe polarization? I know the correct thing to do would be to purchase an original cable, but we don't have time. Importing products here is a tedious process, we've been waiting for this PLC 3 months more than we were promised, so we are already late with our client.The message timed out in the local processor. A link layer timeout.
Thank you very much for your time, and I really hope someone is able to help me, as I don't know what else to do.
P.S: Yes, I tried point to point connection with just the one VFD, same results.
P.S.S: I also was able to connect the ATV312 through Modbus to my laptop, using an USB-to-RS485 converter, and using the software SoMove. This means the Modbus connection of the VFD is working.
I could not, however, connect the PLC through Modbus (I programmed it through USB) with the CCW software.