| ??? 12/02/09 06:49 Read: times |
#171376 - Still lots of debugging left Responding to: ???'s previous message |
So, if the Hyperterminal doesn't get any answer, then you shouldn't expect your microcontroller to get any answer either, should you?
Does the modbus test programs receive any answers? If they do, then your first job is to figure out the difference between requests from them contra the manual requests you send out using the Hyperterminal. If they don't, then you have to figure out if you have correctly configured them, and if your cabling is correct and if the modbus protocol has been enabled in the external device etc. My question is still: What have you tried to do to figure out where the problem is? How do you know that 9600 baud is the correct speed? How do you know that there shouldn't be any parity? How do you know that your null-modem cabling is correct? How do you know that your null-modem cabling is correctly connected? How do you know that the device is using RTU? How do you know that the device have Modbus enabled? How do you know that the request is reaching the device? How do you know that the device isn't answering, but the answer not reaching the PC? How do you know that your timing is ok? |
| 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 |