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DPM-MRTU: Digital Multi-Range Three Phase Voltage Monitor


Voltage Ranges:

• 115 to 277VAC, 1Ø

• 200 to 600VAC, 3Ø


Digital Display:

• Line Voltages

• Frequency

• Imbalance %

• Output Relay Status

• Last 4 Faults

• Set-Up Menus 



SPDT Contacts



The DPM is a single and three phase voltage monitor that verifies that the line voltage is within the parameters selected by the operator. Typically, the relay output is connected into the control circuit to disable equipment when the line voltage goes outside the selected parameters to avoid or minimize damage to equipment (motors, blowers, compressors, pumps, etc.)


The ModbusRTU feature also allows the DPM to communicate the operational information to equipment controls and building automation systems. This allows use of the data to more efficiently operate equipment and alert operators on the status of the line voltages.

With the supply voltage applied to the DPM, the DPM will monitor the line voltages (single or three phase). If the voltages are within the operator selectable parameters, the output relay will be energized. If the line voltages drift outside the selectable parameters, the output relay will be de-energized with the opportunity to disconnect sensitive equipment from the line voltage until the problem is corrected.


The ModbusRTU option allows the line voltages and all of the settings to be transferred to a controller or building automation system. The communications allows for all of the current line voltages and set point to be communicated via ModbusRTU. The DPM also allows for the controller to select/change the line voltage the DPM is being set for.



Line Voltage: 115 to 277VAC, 1Ø
                      200 to 600VAC, 3Ø

Supply Voltage:
12VDC, 24VDC, 24VAC, 120VAC & 240VAC,1Ø

Display: 16 Character, 2 Line, LCD back lighting

Adjustments: Membrane Buttons & Display

Modbus Unit Addresses: 1 to 247 (Default unit address is 49)

Over/Undervoltage: Adj. 7% to 15%

Phase Imbalance:  3% to 10%

Phase Rotation: A – B – C


      Trip Delays:  Adj. 2 Sec. to 10 Sec.

      Reset Delays: Adj. Manual Reset to 5 Minutes

Power Consumption: 2.1VA

Output Contacts:  SPDT (Single Pole Double Throw)

      10 Amps @ 120VAC

      6 Amps @ 277VAC

      1/8HP @ 12/277VAC

      5 Amps @ 30VDC

Communications Output: ModbusRTU  

      Accuracy: ±1%                                                             

      Baud Rate: 19.2K                                                           

      Parity: None                                                           

      Data:  (Function Code 3)   

Contact factory for complete set of register addresses and values.


Mounting: Surface Mounting (2 screws)


      Line Voltage: (3) 0.25” Push-On Tabs or Pluggable Blocks

      Output Contacts: (3) 0.187” Push-On Tabs or Pluggable Blocks

      Supply Voltage: (2) 0.187” Push-On Tabs or Pluggable Blocks

      ModBus: (3) Pluggable Terminal Block

Packaging: Surface mounting with Epoxy fill; 5” x 3” x 2”


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