Anti wind reset in PID

[RussB]

In Table_bit press F6 (bin) to see what bits are "ON".

In Bitset1_1 bit 16 of %R1111 will turn ON.

In Bitset_1 nothing will happen or maybe bit 6 of %R1112 will come "ON"

This is of course assuming that there is no logic in the program after this logic that turns the bits "OFF".

 

[Steve Bailey]

Do not forget that the BIT_SET instruction turns the bit on. It will remain on until some other action turns it off. The BIT_SET function with a LEN parameter = 1 operates over a range of 16 bits. There is no bit 22 in that range. The value of -32768 is the result of setting the most significant bit.

Your first jpg was your attempt to set bit 22.
Your second jpg was the logic to set bit 16.
Your third jpg shows the result of setting bit 16. Notice the bit pattern in %R1111 immediately below and to the right of the word "REGISTER".

I don't see where you have tried setting bit 4.

 

[jcp]

Hi;
I do it but not sure is it correct or wrong.
Now i write 5 on bit and see in the table %R1111 have 16 and %R1111 on bit instruction is 0010.
IN the manual the defination of config word as under
BIT 0= sp-pv or pv-sp
Bit 1= OUtput polarity
Bit 2= derivative action on PV
bit 3= dead band action
bit 4= anti reset wind
So i use decimal 5 to turn the anti reset wind.
Am i right?
Reagrds

 

[Steve Bailey]

16 decimal = 10 Hex = 0000000000010000 binary

The bit that's ON in the binary representation is bit 4 if you call the least significant bit zero. The same bit is bit 5 if you call the least significant bit 1. The manual calls the least significant bit zero. The BIT_SET instruction calls the least significant bit 1.

 

[jcp]

Hi;
It means its ok and anti reset wind in action.
Do u give me one sugesstion about dead band in the PID
If its bit is zero and the error with in dead band the error forced to zero. If it is one then error= Error-deadband limit
Can u advise me which one is best? I think the bit is must be one if PV overshoot 10% from the setpoint.
For example if setpoint is on 84% PV goes 84.6 and falls back to 83.9 and then set at 84.
If i used Error=ERROR- DEADBAND LIMIT is it minimize becuase KP and KI is now almost set.

Regards

 

[Steve Bailey]

Let's say your deadband is +/- 2, your SP is 100, and your PV is 75.

With the bit equal to zero, the magnitude of the error will be 25. With the bit equal to 1, the magnitude of the error will be 23. The CV is calculated based on the error.