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Technical support / Re:RS485 communication issue
« on: December 06, 2005, 06:48:25 PM »
thanks a lot. I will try it out.
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Technical support / RS485 communication issue
« on: December 06, 2005, 01:10:36 AM »
I am having some issue with RS485 communication.
I am using three H series PLC connected via a RS232-RS485 converter from Tri-logi. The converter is set to auto mode and response time has been adjusted to maximum which I found has best result.
I use C++ to program the communication between PC and PLC. Basically this is the sequence I am doing:
1. Turn RTS on.
2. Put data to transmit buffer and wait for data to be sent out completely.
3. After data is sent out completely, wait for a period of time, 110 ms.
4. Turn RTS off and read the input buffer.
The issue I am facing now is that quite frequently I will read back some garbage string. For example, if I send a command "@03RR0000"plus start and CR, most time I can read back correctly, but some time I will read back something not started with ""@03RR" at all.
Can you help on this? Thanks a lot.
I am using three H series PLC connected via a RS232-RS485 converter from Tri-logi. The converter is set to auto mode and response time has been adjusted to maximum which I found has best result.
I use C++ to program the communication between PC and PLC. Basically this is the sequence I am doing:
1. Turn RTS on.
2. Put data to transmit buffer and wait for data to be sent out completely.
3. After data is sent out completely, wait for a period of time, 110 ms.
4. Turn RTS off and read the input buffer.
The issue I am facing now is that quite frequently I will read back some garbage string. For example, if I send a command "@03RR0000"plus start and CR, most time I can read back correctly, but some time I will read back something not started with ""@03RR" at all.
Can you help on this? Thanks a lot.
Pages: [1]