NI PID Toolkit

[Dr Jon Atkinson]

Hello

Has anyone here ever used the PID Toolkit add-on. I am having real problems
getting the toolkit to control a small furnace we have built (which is
definitely controllable, as we have controlled it using a Eurotherm
controller with no problems whatsoever).

The autotune feature actually comes up with PID parameters which make the
control worse.

The software seems to apply too much power when it wants to heat the furnace
up, and thus we get overshoot. When trying to hold at a steady temperature
using the Eurotherm, it used to constantly apply a particular voltage to
maintain the temperature - however the PID Toolkit from National Instruments
never seems to want to hold the power on, rather it puts in a huge amount of
power for a
short time, then shuts it off, etc etc

I have tried using the PID parameters which the Eurotherm calculated (which
worked fine) and these do not work very well at all with the NI toolkit.

Has anyone ever succesfully used this software?

Thanks

Jon Atkinson

[Mike Manzheliy]

Hello
Yes, I am used successfully this toolkit and Field Point.
I think, you can try to use PI mode not PID.
With this mode you can tuning your parameters more ease.
If your equipment will be working O.K. therefore you have to change your PID
parameters.
Cheers
Mike Manzheliy


Dr Jon Atkinson wrote:

> Hello
>
> Has anyone here ever used the PID Toolkit add-on. I am having real problems
> getting the toolkit to control a small furnace we have built (which is
> definitely controllable, as we have controlled it using a Eurotherm
> controller with no problems whatsoever).
>
> The autotune feature actually comes up with PID parameters which make the
> control worse.
>
> The software seems to apply too much power when it wants to heat the furnace
> up, and thus w
e get overshoot. When trying to hold at a steady temperature
> using the Eurotherm, it used to constantly apply a particular voltage to
> maintain the temperature - however the PID Toolkit from National Instruments
> never seems to want to hold the power on, rather it puts in a huge amount of
> power for a short time, then shuts it off, etc etc
>
> I have tried using the PID parameters which the Eurotherm calculated (which
> worked fine) and these do not work very well at all with the NI toolkit.
>
> Has anyone ever succesfully used this software?
>
> Thanks
>
> Jon Atkinson

[srm@viewpointusa.com]

We have used the NI PID toolkit and it does work. As with all PID
algorithms, getting the parameters right is most of the problem.
When I have experimented with the PID autotune feature, it seamed to expect
a (relatively) fast response (not a furnace) and would get easily confused.

It sounds like your P is much too large and your I term is not large enough.

Stu McFarlane

"Dr Jon Atkinson" wrote in message
news:8v09tn$r4f$1@usenet.bham.ac.uk...
> Hello
>
> Has anyone here ever used the PID Toolkit add-on. I am having real
problems
> getting the toolkit to control a small furnace we have built (which is
> definitely controllable, as we have controlled it using a Eurotherm
> controller with no problems whatsoever).
>
> The autotune f
eature actually comes up with PID parameters which make the
> control worse.
>
> The software seems to apply too much power when it wants to heat the
furnace
> up, and thus we get overshoot. When trying to hold at a steady temperature
> using the Eurotherm, it used to constantly apply a particular voltage to
> maintain the temperature - however the PID Toolkit from National
Instruments
> never seems to want to hold the power on, rather it puts in a huge amount
of
> power for a short time, then shuts it off, etc etc
>
> I have tried using the PID parameters which the Eurotherm calculated
(which
> worked fine) and these do not work very well at all with the NI toolkit.
>
> Has anyone ever succesfully used this software?
>
> Thanks
>
> Jon Atkinson
>
>
>
>

[Joe Losco]

Depending on what you are doing and how fast you need to get up to temperature, you can use a Setpoint Profile (PID Setpoint Profile.vi)  to slowly ramp to the temperature instead of going from 0 to say 500 degrees immediately.  You can set a ramp from 0 to 500 degress over say 2 minutes or 60 minutes.