Initialize PID(190)

[aVi]

I'm working on integrating a PID for tension control into a CS1G-H processor. I have already been able to successfully implement this PID in a similar application with a Siemens 313C PLC using their integrated PID. So far I am optimistic but, Siemens has an Initialize integral action bit which presets the integral component of the PID when set. I have been unable to recreate this function in Omron's PID. Is such a function possible with PID(190)?

[Sleepy Wombat]

You are using the H series - i thought that the PID instruction in this series plc had an auto tune function. Anyways, I am a bit unclear as to what you mean by pre set the integral. You can set the P I and D via the corresponding memory areas determined by your control word. There is a setup bit that alows dynamic chaning of the P I and D values while the PID is executing, if you do not set this bit then the P I and D settings will only be initalised on the up of the enable signal line for the PID. Remember to set a value for the T constant also.

[ParaffinPower]

Hi SW I think the OP meant Reset, not Preset the integral. I've had a look, and can't find anything, I'm afraid. I guess one of the 30 or so Words the PID intruction uses is the integral portion of the output. I'll try to decode it next time I'm using it... Edit: Not sure here, but can you change the integral gain to 9999 (disabled); I don't know if the integral action will return to what it was or start at zero again when you re-instate the 'correct' I gain? Pp Edited December 13, 2010 by ParaffinPower