Siemens S7-200 Data loss

S

Thread Starter

Stress911

I have a system sending over data though the PPI cable to the S7-200 226 model... The data received is ASCII coming through at 9600 kbs the data string is about 17 characters but I only grab the 5 that I need...

Every so often I lose one character. I've tested the sending unit with a null modem cable and Hyper-terminal and found it was working good.

We have 20 of these systems and they seem to lose data just once in a blue moon and of course the customer is not happy with "once in a while"

Any ideas?
 
C

curt wuollet

That's the worst kind of problem to find. In the meantime could you check the length and have it resend if it's bad? Or is it a one shot deal?

Regards
cww
 
Hello,

What is the frequency the device is sending to the S7-200? I have seen cases in which the PLC cannot process a turnaround as fast as, for example, a PC. I have seen this in S7-200.

Other data might help, is it the last, first or a character in the middle? Is it always the same character position or same character value?

Is it due to a ring buffer wrap around?

Good luck,
Mark
http://www.peakhmi.com/

 
>What is the frequency the device is sending to the S7-200? I have seen cases in which the PLC cannot process a turnaround as fast as, for example, a PC. I have seen this in S7-200.<

The sending device was an RS-232 test unit, just a one shot send.

We changed the interrupt from 8 to 23 to grab data at an earlier time. No more data loss...

Sorry I didn't get back sooner...
 
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