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cp340 output spike

Created by: Frosty at: 3/9/2009 4:53 PM (1 Replies)

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3/9/2009 4:53 PM	Rate (0)
Frosty Posts: 4 Rating: (0)	Hey all; I have an issue with a Siemens S7-300 plc and outputting data. The Process; I'm sending out certain values during a test these values are pressure, volume, setpoint and test time. These values are being sent via cp340 to a pc where i'm graphing the results. All of this is working fine, however the problem is that when a value changes by a factor of 10 there seems to be a spike. i.e. The time is being sent out in ms, when the time changes from 9sec to 10 sec it jumps to 100sec for one value then back to 10sec. i've also noticed this in the pressure value where it drops out. i.e the pressure is rising to meet the setpoint and when changing from 9bar to 10 bar it drops to almost 0 then the next value is back at 10 bar. if anyone has seen this before or may have an idea on what may be wrong i'd appreciate the advice, any other questions? just post them and i'll answer. Regards.
Frosty Posts: 4 Rating: (0)
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3/10/2009 6:36 AM	Rate (1)
Eastern Posts: 557 Rating: (64)	hi you can check following posibility: 1) CPU scan time. 2) cp340 output spikeprgram you can put is OB 35 & Change the time in two posibility: a) in hardware configuration change scan time 50ms b) in hardware configuration change scan time 5ms if your plc scan is suppose 50 ms that mean in 1 sec 20 scan per sec if it is 5ms that mean in 1 sec 200scan ,so check these posibility & tell me the result, & also send me the diagnostic buffer. regards vivek
Eastern Posts: 557 Rating: (64)
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