ATR121 Setppoint Temperature Engineering Units

mboyd81l · Post by **mboyd81l** » 30/06/2025, 14:11

Hi,
I recently had to replace a cooling unit that has this controller in it. This unit came configured in Fahrenheit and I need it to be in Celsius to match the other controllers in our process. I was able to change parameter "GrA" to Celsius, however the setpoint is still showing in Fahrenheit. Is there a separate parameter for setpoints? What is the procedure to change the setpoint units?

Post by **Pixsys tecnico 7** » 30/06/2025, 14:46

Good morning,
The setpoint value is just a numerical threshold used as a reference to open or close the output that is associated with.

It doesn't change based on the parameter "GrA".

There is no separate parameter associated with the setpoints units.

mboyd81l · Post by **mboyd81l** » 30/06/2025, 15:57

So, why does the setpoint still show in F° when "GrA" is set to C°?

Post by **Pixsys tecnico 7** » 30/06/2025, 17:11

The setpoint is never shown in °F or °C,

it's just a numberical threshold , and it doesn't refere to Par. 26 "Gra".

mannertwang · Post by **mannertwang** » 29/09/2026, 11:53

mboyd81l wrote: ↑30/06/2025, 14:11 Hi,
I recently had to replace a cooling unit that has this controller in it. This unit came configured in Fahrenheit and I need it to be in Celsius to match the other controllers in our process. I was able to change parameter "GrA" to Celsius, however the setpoint is still showing in Fahrenheit. Is there a separate parameter for setpoints? What is the procedure to change the setpoint units? Stickman Hook

That clears it up. The key point is that the setpoint is only a numerical threshold and isn’t tied to the °C/°F setting, which explains why changing GrA doesn’t change how the setpoint value appears.

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