plc softer problem

[shashi]

hi have a problem in plc prog. when i will give a stroke to a plc it over shoot it after 3 min. what is the problem.

 

[jstolaruk]

Could you re-state your question please? What hardware and software are you using?

 

[bluebyu]

Oh no!

I sense another very large thread comming on. The last question like this lead to many getting involved.

Lost production in the world wide automation field was at historic highs.

 

[Ken M]

In shashi's post he says he already has the problem, and from the last four words it appears all that we have to do is say what the problem is. It's a kind of game. You know ... he mimes it for us, how many words, syllables etc. Or maybe we're allowed to ask him questions but he's only allowed to answer 'yes' or 'no' and we have to get it in 20 questions or fewer.

This could be good ...

Ken

 

[stasis]

judging by the original posters comment (before the question), he already knows the problem...he is trying to trick us!

The problem is that when he gives the plc a 'stroke' (could be kinky, could be medical, could be with a BFH), it overshoots after 3 minutes (could it be that he is 'stroking' it for 3 minutes, if with the BFH I don't see how it does anything afterwards)

...there is the problem! The solution, on the other hand will require knowledge that we do not possess,i.e., the exact set-up that the OP has. Type of plc, the actual program, his definition of 'stroke'...

 

[Rod]

Using my powers of devination coalesing out of the ethereal mists is the Answer AND then the Question:

ANSWER: Your additive code is stepping on or over-writing an adjacent PLC memory space.
SOLUTION: Double check your Memory assignments - possibly you are using double long words or are not testing for overflow errors

QUESTION: After 3 minutes of operation the machine's pneumatic reject piston counter is too high
---
Alternate

ANSWER: Your machine's hydraulic system has warmed up after 3 minutes of operation allowing the piston to overshoot or the mechanical parts require better lubrication.
SOLUTION: Refine your PID and/or add a heater to your fluid system. If it were my machine I would try doubling the D value as a test.

QUESTION: After 3 minutes of operation the machine's piston overshoots the final position point. Could this be a temperature problem?

These will only work if your PLC is one of the dark gray units with red and green LEDs.

Rod (The scourge of CNC devinations)

 

[Rod]

by 'softer' do you mean 'sorter'?

I may have made a mistake here - - nahh

Rod