






Features
- 4-20 mA Loop Set Point Generator
- Panel Mount or NEMA 4X
- 4-20 mA or 3-21 mA Output Ranges
- Set Point Displayed as 0-100%, 4-20 mA, or 3-21 mA
- Valve Position Displayed as 0-100%
- Built-in Dial for Changing Output
- Backlit Display
- Coarse or Fine Set Point Adjustment
- ± 0.5% Output Accuracy
- 0.01 Display Accuracy
- 15-30 VDC Power Requirement
- < 500 ohms Sampling Resistance
- Decals Provided for %, mA, Open, Closed, and Custom
Overview
The PD420/21 set point generator and the PD460/61 valve positioner provide a convenient way to generate a 4-20 mA signal that can be used to control another device.
Both feature a backlit LCD. The PD420/21 set point generator can be programmed to display 0-100%,
4-20 mA or 3-21 mA and output either 4-20 mA or 3-21 mA. The PD460/61 valve positioner is programmed to display a value of 0-100% relating to the 4-20 mA output. A built-in dial is provided to vary the displayed / output value. The dial may be programmed for coarse or fine adjustment.
The signal generator and valve positioner are both available as a panel mount or NEMA 4X version. In addition, NEMA 4X enclosures are provided to house up to three of the panel mount versions.
Decals are provided for %, mA, Open, and Closed for the user to apply to the faceplate. There is also a decal with a white background for the user to write a custom label.
Available Enclosures
Connections

Set Point Generator / Valve Postioner
Powered by 24 VDC Supply

Set Point Generator / Valve Postioner
Powered by Controlled Device
Dimensions Units: Inches (mm)
PD420/60 Panel Mount Dimensions

Front View

Back View
Notes:
- Panel cutout required: 3.0" x 1.6" (77 mm x 40 mm)
- Panel thickness: must be greater than 0.06" (1 mm)
- Mounting brackets snap in place for easy mounting
PD421/61 NEMA 4X Dimensions

Front View

Side View
Specifications
Output Accuracy: ± 0.5%
Output Ranges: 4-20 mA or 3-21 mA
Display: 0.3" (8 mm) high backlit LCD
Display Accuracy: 0.01
Display Modes: Current, 0-100%, 0-50.0 Hz
Display Change Adjustment: User may program coarse and
fine adjustments such that each pulse on the dial results in a
change of between 1 and 50 counts on the display.
Front Panel: NEMA 1 (PD420 and PD460)
Enclosure: NEMA 4X (PD421 and PD461)
Decals: (2 each): %, mA, Open, Closed, and white
background for the user to write a custom label.
Operating Temperature Range: -4 to 140°F (-20 to 60°C)
Connections: Removable Screw Terminal Block
Power Requirement: 15-30 VDC
Sampling Resistance: Less than 500 Ω
Programming Instructions
Parameter Table 1:
Entering F002-F007 (FXXX System Settings) requires a password “+--+” first:
Index | Designation | Comments |
F001 | Output Mode | 0: Coarse tuning mode; use F004 to adjust increment value per click 1: Fine tuning mode; use F005 to adjust increment value per click 2: Quick output; use F100 to enter number of quick output settings 3: Automatic curve output: Use F200 to enter number of curves |
F002 | Output Range | 0: 4-20 mA 1: 3-21 mA |
F003 | Display Range | 0: Current 1: 0-100% 2: 0-50% |
F004 | Coarse Tuning Increment Value | 1-50 Addition and subtraction for each click. Disregard decimal point (1-50) x10 |
F005 | Fine Tuning Increment Value | 1-50 Addition and subtraction for each click. Disregard decimal point (1-50) x10 |
F006 | Auto Save of Adjustment Value | 0: Not automatically saved. Need to press knob to save 1: Automatic save |
F007 | Calibration | Factory set only |
Default Values | Set Point Generator | Valve Positioner |
Coarse tuning mode | Increments of 0.10 | Increments of 1 |
Output range | 4-20 mA | 4-20 mA |
Display mode | 4-20 mA | 0-100% |
Change from coarse to fine tuning mode:
- Press and hold the knob for two seconds until F001 appears.
- Press the knob again
- Change the number from 0 (coarse tuning mode) to 1 (Fine tuning mode)
- Press the knob again
Entering Passwords:
- Rotate knob one click clockwise for “+”
- Rotate knob one click counter-clock for “-“
- Press the knob to confirm
Change the output range from 4-20 mA to 3-21 mA:
- Enter the password as described above
- The F002 menu is used to change the output range. Turn knob until the desired parameter number appears and press enter:
a. 0: 4-20 mA
b. 1: 3-21 mA - Keep turning the knob until FEnd appears and press the knob to exit programming
Change the display from current (4-20 or 3-21 mA) to 0.0-100.0% or 0.0-50.0%:
- Enter the password as described above
- Turn the knob once clockwise and F003 appears.
- Press the knob and turn the knob until the desired parameter number appears and press enter:
a. 0: Current
b. 1: 0.0-100.0%
c. 2: 0.0-50.0% - Keep turning the know until FEnd appears and press the knob to exit
Change the value for how much each click on the knob adjusts coarse tuning:
- Enter the password as described above
- Turn the knob twice clockwise until F004 appears.
- Press the knob and turn the knob until the number that represents how much the display will change with each click appears and press enter.
- Keep turning the knob until FEnd appears and press the knob to exit
Change the value for how much each click on the knob adjusts fine tuning:
- Enter the password as described above
- Turn the knob three times clockwise until F005 appears.
- Press the knob and turn the knob until the number that represents how much the display will change with each click appears and press enter.
- Keep turning the know until FEnd appears and press the knob to exit
Change from pressing the knob to save programming to automatic save:
- Enter the password as described above
- Turn the knob four times clockwise until F006 appears.
- Press the knob and turn the knob until the desired parameter number appears and press enter:
a. 0: Need to press knob to save programming
b. 1: Automatic save - Keep turning the know until FEnd appears and press the knob to exit
Parameter Table 2:
Entering F100... (Quick Output Settings) requires password “+-+-“ first
Index | Designation | Comments |
F100 | Number of quick settings | 0: Not used 2-9: Number of points |
F101-109 | Output value of up to 9 points | Range: 3.00-21.00 mA (F100 must be > 0) |
Programming Quick Output Points:
- Press and hold the knob for two seconds until F001 appears.
a. Press the knob again
b. Change the number from 0 (coarse tuning mode) to 2 (Quick Output Settings)
c. Press the knob again to return to operation mode - Press and hold the knob for two seconds until F001 appears.
a. Enter password per instructions above to: +-+- - Press the knob and F100 appears
Adjust the knob until the desired number of Output Points appears and press the knob. - Enter in Output Points
a. F101 and value; enter all points
Parameter Table 3:
Entering F200... (Curve Output Settings) requires password “-+-+“ first
Index | Designation | Comments |
F200 | Number of curves | 0: Not used 1-9: Number of segments |
Ft01 | Curve 1 run time | 0-999 seconds (F200 must be > 0) |
FA01 | Curve 1 start current | Range: 3.00-21.00 mA |
Fb01 | Curve 1 end current | Range: 3.00-21.00 mA |
Ft02 | Curve 1 run time | 0-999 seconds |
Fb09 | Curve 1 end current | Range: 3.00-21.00 mA |
Programming Curve Output Points:
- Press and hold the knob for two seconds until F001 appears.
a. Press the knob again
b. Change the number from 0 (coarse tuning mode) to 3 (Automatic curve output)
c. Press the knob again to return to operation mode - Press and hold the knob for two seconds until F001 appears. a.Enter password per instructions above to: -+-+
- Press the knob and F200 appears
a. Press knob and enter the number of curves to be programmed
b. Set Ft01: Run time for curve (0-999 seconds)
c. Set FA01: Start current value (3.00 to 21.00 mA)
d. Set Fb01: End current value (3.00 to 21.00 mA)
e. Repeat for remaining curves
Examples of Automatic Curve Output Settings:
![]() | F200=1 Ft01=10 FA01=4 Fb01=20 |
![]() | F200=2 Ft01=10 Ft02=10 FA01=12 FA02=6 Fb01=12 Fb02=6 |
![]() | F200=8 Ft01=2 Ft02=3 Ft03=3 Ft04=2 Ft05=2 Ft06=3 Ft07=3 Ft08=2 FA01=9 FA02=11 FA03=12 FA04=11 FA05=9 FA06=11 FA07=12 FA08=11 Fb01=11 Fb02=12 Fb03=11 Fb04=9 Fb05=11 Fb06=12 Fb07=11 Fb08=9 |

