Luka0204

GX Works 3 - PID control

6 posts in this topic

Hi,

I am using PID function (PID operation instruction) from GX Works 3 library but it doesn't work. I set all necessary parameters (sampling time, direction and upper/lower limit values + KP, TI). My input PID_Par is array of 25 points (in manual is written: "*1When auto tuning is not used, the same number of points are occupied as when the step response method is used.").

For example, in GX Works 2, PID function works ok.

Did someone have similar problem? Does someone have mitsubishi library (GW Works 3) with PID function that works correctly?

 

Regards

Luka

 

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Which PLC are you using iQ-F or iQ-r ?

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8 minutes ago, Gambit said:

Which PLC are you using iQ-F or iQ-r ?

Sorry, I forgot to mentioned--- iQ-R (RO4 CPU)

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On 8/31/2018 at 5:00 PM, Luka0204 said:

Hi,

I am using PID function (PID operation instruction) from GX Works 3 library but it doesn't work. I set all necessary parameters (sampling time, direction and upper/lower limit values + KP, TI). My input PID_Par is array of 25 points (in manual is written: "*1When auto tuning is not used, the same number of points are occupied as when the step response method is used.").

For example, in GX Works 2, PID function works ok.

Did someone have similar problem? Does someone have mitsubishi library (GW Works 3) with PID function that works correctly?

 

Regards

Luka

 

In GXW3 PID have some strange difference with GXW2.

1) PID doesn't work if you place it in FB. Works only in program body (FC i didn't test)

2)Array of PID parameters must be declared global variables with preset address

3)All inputs/outputs of PID (s1,s2,s3,D) also must be declared as global variables with preset address

This is that i have understood during the working with fx5u plc.

 

Снимок.PNG

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Hi,

once again question regarding the PID control.

When I am using PID Control Instructions (Exact Differential) and I am limiting Manipulated Value (MVLL, MVHL), from 0 to 32000. But, when I run a PLC with these limits, I can't get MV more than 2050. In manual is mentioned that PID limit can be restricted (-50, 2500) or not (-32768, 32767). How to disable PID limit restriction to get limit range (-32768, 32767)?

Regards

Luka

p.s. Thanks to Clear Mind for previous answer

 

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On 10/19/2018 at 1:49 PM, Luka0204 said:

Hi,

once again question regarding the PID control.

When I am using PID Control Instructions (Exact Differential) and I am limiting Manipulated Value (MVLL, MVHL), from 0 to 32000. But, when I run a PLC with these limits, I can't get MV more than 2050. In manual is mentioned that PID limit can be restricted (-50, 2500) or not (-32768, 32767). How to disable PID limit restriction to get limit range (-32768, 32767)?

Regards

Luka

p.s. Thanks to Clear Mind for previous answer

 

Hi,

solution lies in special register SD 792 where for loop 1 I needed to activated bit b0 to set 'No limit restriction'.

Regards

Luka

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