| ??? 12/03/09 15:40 Read: times |
#171441 - I would do this... Responding to: ???'s previous message |
Hi Kamran,
If I was in your place I would use the following circuit to test the communication between the 2 PLCs. 
Use the PC, to monitor data that is flowing between the 2 working PLCs. I Never use a HyperTerminal; but I use Terminal.EXE (freely downloadable from the net, google it and you will get it). With this much setup connected: compare the data exchanged between PLCs, with that mentioned in the manuals. If it matches, then on Terminal.EXE you will see BaudRate, DataBits, StopBits, Parity, etc. settings required to get your Modbus working. Use the same settings in your microcontroller product, and it should work. I have done this many times and It has never failed me even once. |
| Topic | Author | Date |
| Modbus | 01/01/70 00:00 | |
| What testing have you done? | 01/01/70 00:00 | |
| Don't use hyperterminal | 01/01/70 00:00 | |
| modbus | 01/01/70 00:00 | |
| modbus | 01/01/70 00:00 | |
| Still lots of debugging left | 01/01/70 00:00 | |
| Modbus | 01/01/70 00:00 | |
| Not very helpful | 01/01/70 00:00 | |
| Modbus | 01/01/70 00:00 | |
| Still need to break the problem down into smaller steps | 01/01/70 00:00 | |
| Modbus | 01/01/70 00:00 | |
| modbus | 01/01/70 00:00 | |
| modbus | 01/01/70 00:00 | |
| Parity | 01/01/70 00:00 | |
| Oscilloscope results? | 01/01/70 00:00 | |
| open source | 01/01/70 00:00 | |
| Also RTU Framing | 01/01/70 00:00 | |
| Framing, addressing etc has been discussed | 01/01/70 00:00 | |
| modbus | 01/01/70 00:00 | |
| Bad CRC order!! | 01/01/70 00:00 | |
| modbus | 01/01/70 00:00 | |
| modbus | 01/01/70 00:00 | |
| Don't know why, | 01/01/70 00:00 | |
| Comparison with something known working | 01/01/70 00:00 | |
| what device address | 01/01/70 00:00 | |
| modbus | 01/01/70 00:00 | |
I would do this... | 01/01/70 00:00 |