How to Setup the PXU Process Control as a Digital Potentiometer

06 Jun 2025

 

When used in manual percentage output mode, the PXU series of process controller can be used as a digital potentiometer. Models, with the 4-20 mA retransmit function, can have this output scaled to track setpoint value, percentage output value, or process input value. 

 

APPLICABLE PRODUCTS 

Any PXU series process controller with analog voltage or current main control output.  Models with the optional 4-20 mA retransmit function can also be used. 

 

PRE-REQUISITES

  • PXU control model must support analog voltage or current output. The optional 4-20 mA retransmit function also can be configured for manual output.

 

IN THIS ARTICLE 

 

Input Jumper Setting

If feedback is 4-20mA or the 4-20mA output is looped through the input, then the internal jumper (JP8) must be moved to the 4-20mA position.

 

Meter Feedback Signal

By placing the controller in the manual mode, the analog output can be adjusted to the desired percentage by changing the bottom display value. In order to see the output in engineering units, the output will need to be wired to the input. If using a current output, the input will need to be wired in series with the output and the load. If using a voltage output, the input will need to be wired in parallel with the output and load. See below for recommended settings:

 

Programming note: (Only non-factory settings are shown) 

Reference the PXU Product Manual for more information.

Parameter Loop Setting

trnF=USEr

Hidden Loop Settings

1-IN

tYPE = feedback signal type, 4-20, or 0-10V 

DSP1 = Engineering units: low value of feedback signal 

DSP2 = Engineering units: high value of feedback signal 

 

3-LC 

SP=LOC

OP1=DISP 

Suggest setting all other parameters to the LOC menu 

 

Other Programming Options (Model Dependent)

Retransmit models PXUxxCx0

4-20 output (Active, powered)

Programming: (Only non-factory settings are shown.)

Hidden Menu Settings 

1-IN

DECPT=user defined

2-OP

ANAS = OP1

3-LC

SP=LOC

OP-1 = DISP 

 

 Wiring: Output

1/16 Din models 15 – 16 + to device

1/4 & 1/8 Din models 18 – 19 + to device

If monitoring the output on the top line, then add the following:

Programming: (Only non-factory settings are shown.)

Hidden Menu Settings

1-IN

Type=4-20

dSP1= (ANLO values)

dSP2= (ANHI values)

Input Range Jumper

Open controller, place JP8 jumper on both pins

Wiring:

1/16 Din models 15 – to device (16 + jump to 11) 12 is now + to device

1/4 & 1/8 Din models 18 – to device (19 + jump to 11) 12 is now + to device

 

 

Models without Retransmit Option (PXU3x0x0 PXU3xAx0 PXU3xBx0 PXU3xDx0)

4-20mA output (Active, powered)

Programming: (Only non-factory settings are shown.)

Parameter menu setting

trnF= MAN or USER

Hidden Menu Settings 

3-LC

SP=LOC

OP1=DISP

Suggest setting everything else to LOC.

Wiring: Output

1/16 Din models 6 – 5 + to device

1/4 1/8 Din models 9 – 8 + to device

Monitoring the output on the top line, then add the following:

Programming: (Only non-factory settings are shown.)

Hidden Menu Settings

1-IN

Type=4-20

dSP1= (0.0 or engineering units: low value)

dSP2= (100.0 or engineering units: high value)

Input range Jumper

Open controller, place JP8 jumper on both pins

Wiring:

1/16 Din models 6 – to device (5 + jump to 11) 12 is now + to device

1/4 & 1/8 Din models 9 – to device (8 + jump to 11) 12 is now + to device

 

 

Models without Retransmit (PXU4xxx0)

0-10V output

Programming: (Only non-factory settings are shown.)

Parameter Menu Setting

trnF= MAN or USER

Hidden Menu Settings 

3-LC

SP=LOC

OP1=DISP

Suggest setting everything else to LOC

Wiring: Output

1/16 Din models 6 – 5 + to device

1/4 & 1/8 Din models 9 – 8 + to device

Monitoring the output on the top line, then add the following:

Programming: (Only non-factory settings are shown.)

Hidden Menu Settings 

1-IN

Type=0-10

dSP1= (0.0 or engineering units: low value)

dSP2= (100.0 or engineering units: high value)

Wiring:

1/16 Din models 6 – 5+ to device (5 + jump to 11 and 6 to 12)

1/4 & 1/8 Din models 9 – 8+  to device(8 + jump to 11 and 9 to 12)

 

 

ADDITIONAL INFO 

Link to PXU Product Manual 

PXU Product Manual