SAT Test for Emerson Controller

[dung.ho]

Hi,

I have to test a control logic that required to change the input temperature as the process variable from thermocouple transmitter on the field. Would anyone know which way is the best to do this on Emerson Controller? Since it doesn't let me change the process variable on the PLC Programming. Thanks.

 

[Steve Bailey]

Are you trying to create a simulated process variable for test purposes instead of using the actual measured temperature from the thermocouple? Which Emerson processor are you using?

 

[dung.ho]

Yes. Since I would like to change the temperature to the point that I wanted. Should I use Signal Generator (4-20mA) and create a scale block for it on PLC?
I use emerson ic695cpk330.

 

[Steve Bailey]

The 'Q' output of the arithmetic function blocks can be a %AI address. By adding a rung to calculate a value in the %AI address you're using for the PV just before the PID function, you can override the actual signal from the thermocouple.

 

[dung.ho]

Yes. I think I did that already. I created another rung for scaling block with NC-Contact bit on the front and the input is a REAL bit. And, I used the same NO-contact to block the scaling block which takes the actual measured temperature from thermocouple.
I would say if I wanted to do this but not using the way above. Would you know any way? Thanks.

 

[Steve Bailey]

Does your method work? If so, you don't need my advice on a different way to accomplish what you want.
If your method doesn't work, post what you've done and I'll offer suggestions. I'm having a hard time interpreting what you're asking.

 

[the_msp]

As this is an SAT, not FAT, surely the best method is to actually place the thermocouple into a calibrated water bath etc?

 

[dung.ho]

Thank you guys so much.