LJ Engineering

Model 487 Electronic Vacuum Regulator

The Model 487 Electronic Vacuum Regulator is designed to accept a user's analog control signal generated from a user's electronic system or potentiometer to adjust the set point of the vacuum regulator. Additionally the unit can be configured to operate as an electronic pressure regulator.  Jumper settings on the regulator board allow the user to select the control signal type: external potentiometer, on-board potentiometer or external analog signal up to 5 volts. Two ranges of pressure sensors are available 487-001 (0 to 41 inches of water, 3 in-Hg, 1.5 psi) or 487-002 (0 to 29.5 in-Hg, 760 in-Hg approx. 14.5 psi). Both models are atmospheric pressure referenced, which means their output will be constant relative to the atmospheric pressure. An absolute pressure reference sensing version is available. Two different flow range versions are available for either model regulator. The smallest flow range valve that meets the application's flow requirements should be selected to provide maximum control and resolution. These regulators are also capable of regulating positive pressure up to the same range as specified in vacuum. This regulator is self-relieving, meaning that it will follow a control signal as it is increased or decreased without the need to introduce a leak source or any additional valves to vent vacuum or pressure to obtain the new set point.



Operating Principle

The electronic vacuum regulator accepts an analog control voltage signal, which precisely operates valves as required to maintain the desired set vacuum or pressure. The device can operate either as a electronic pressure regulator or a vacuum regulator. Pressure or vacuum output is controlled in proportion to an analog voltage or potentiometer setting. Its self-relieving operation allows the vacuum or pressure output to automatically track a changing control signal.

Adjustability range, vacuum or pressure:

487-001 full scale range 0 to 41 inches of water (3 inches-Hg , 77 mm-Hg, 1.5 psi)

487-002 full scale range 0 to 29.5 inches-Hg, 760 mm-Hg (14.5 psi)

Power Supply :

15 to 26 volts DC,

180 mA maximum current

Control signal:

Jumper selectable by customer for any of the following options:

  • Control Signal 0 to 5 volts (scalable to less)
  • On-board 25-turn potentiometer
  • Customer supplied 5k or 10k ohm potentiometer


0.34 pounds (155 g)


4.8 inches by 2.3 inches by 1.7 inches high

Port Connections:

1/8 inch inside hose diameter (Tygon R polyurethane recommended)



The model 487 is ideal for applications requiring interface with a user's control system for electrically controlled adjustment of vacuum or pressure in both increasing and decreasing vacuum or pressure directions. Typical uses include leak testing stands, pressure force control devices, vacuum clamping control, vacuum bagging control and countless other electrically adjusted vacuum regulator and electrically adjusted pressure regulator applications. Additionally, the unit can be use as a vacuum pilot stage for our model 470-002 vacuum flow amplifier to control flow rates up to 44 scfm.


Part Number : 487-XXX-Y

-XXX (vacuum/pressure range)

 -Y (flow capacity)
-001 (0 to 3 inches-Hg.)  -1 (5 SCFH open flow) 0.010 inch diameter passage
-002 (0 to 29.9 inches-Hg.)  -6 (25 SCFH open flow) 0.09 inch diameter passage


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