Temp_UM parameter is inaccessible from Programming and Display on TM172

[obscuresc]

Hi all,

I am setting up user configurable temperature and pressure unit support on a TM172DCLWTHP via EcoStruxure Machine Expert - HVAC.

I'm looking at changing the 'Temp_UM' parameter to change the on-board temperature reading and the sensor reading is directly tied to an edit box on the HMI. I have tried to write to it using the parameter link 'sysPar_Temp_UM' and the parameter name directly (Temp_UM) but I am receive no change in sensor values. I can change Temp_UM via Commissioning and it works just fine in changing unit type and the displayed value, and I can successfully read from sysPar_Temp_UM' in Programming.

During compile, I receive errors such as the following (when using sysPar_Temp_UM in Programming);

PROGRAM_MAIN(41) - error G0008: ST => Invalid access to variable

Or when I attempt using 'Temp_UM' in Programming;

PROGRAM_MAIN(39) - error A4097: TEMP_UM => Object not found

How do I go about fixing this so that I have access to 'Temp_UM'?

Cheers,

Jack

[LeTomas · Accepted solution]

Dear @obscuresc ,

I have used the following code in the programming tab of the TM172D:

IF xPET_Select_C THEN

xAux := sysWriteParUINT(ADR(sysPar_Temp_UM), 0); //C
xPET_Select_C := FALSE;
xPET_Select_F := FALSE;
END_IF;

IF xPET_Select_F THEN

xAux := sysWriteParUINT(ADR(sysPar_Temp_UM), 1); //F
xPET_Select_C := FALSE;
xPET_Select_F := FALSE;
END_IF;

You can check the behaviour in the next video:

https://schneider-electric.box.com/s/5emuv4ach0vwj0e9kx28qg2zqc6r2jm1

https://schneider-electric.box.com/s/5emuv4ach0vwj0e9kx28qg2zqc6r2jm1 

Let us know if this works for you.

Best regards,

Leandro

[obscuresc]

Hi @LeTomas,

Thanks for you help, I had forgotten these functions existed.

I ported your solution to the Display tab and it worked as expected.

Cheers,

Jack