Siemens TIA PiD compact block help

[allennzcontrols]

Using siemens block to control pressure level. The PV is pressure in Bar and the output is vsd fan speed in %. What I require is when the PV is high the fan speed to increase to bring down the pressure. However it's doing the opposite eg increase in pressure = decrease in fan speed. Easy way to solve this is to set a negative gain but the block does not accept that
Help!!!

 

[allennzcontrols]

There is an invert control logic check box but it doesn't work when it's checked.. nothing changes

 

[adfox]

Look here for Reverse operation.

https://support.industry.siemens.com/tf/ww/en/posts/tip-pid-fb-pid-compact-v2-x-configured-with-step7-v12/88237/?page=0&pageSize=10

You can always take (output value - 100.0) * -1.0 which will invert value also.

 

[boneless]

Easiest way to change this is to invert the gain.

If you change the settings in the block itself, make sure you are actually downloading them. It can be a little bit fidgety...

 

[cjd1965]

Hi As Boneless said, multiply the gain by -1

 

[adfox]

He already posted that the block doesn't accept that - what is strange

 

[boneless]

You can use an external tag, not the commissioning wizard, to set the gain to negative.