438D Vibration Switch (inch/sec)

An Economical Machine Monitor with Remote Sensor

More than a simple switch, the 438D is a single-channel vibration monitor that can be located in a centralized location, remote from operating equipment. The 438D is on guard ’round the clock, with cost-effective protection of motors, pumps, fans and a wide range of other rotating equipment. It provides continuous digital readout of the vibration level, and signals when a predetermined setpoint level has been reached.


Measurement mode

Velocity (in/sec)

Frequency range

Dependent on tranducer type and any special filtering (See “Transducer Types” below)

Analog output

4 – 20 mA DC, proportional to full scale range

Input power

110V or 220V AC, field selectable


2, adjustable from 0-100% of full scale


LEDs: yellow for “Alarm”, red for “Trip”

438D operating temperature

-20 to +160F (-29 to +71C)


NEMA 4, with hinged cover
Dimensions: 9.5″H x 7″W x 4″D (24.1 x 17.8 x 10.2cm)
Weight: 6.5 lbs (2.9kg)


Flat surface, 8-3/4″ x 4″ (22.2 x 10.2cm) bolt pattern

Cable entry

Transducer cable entry and cable grip provided; power and control cable entry by customer.

Field Adjustable Settings

Full scale range

0 – 1 or 0 – 3 in/sec

Alarm & trip setpoints

0 to 100% of full scale range

Relay time delay

0 to 20 Sec per relay

Relay state

Normally de-energized (open below setpoint) or normally energized (closed below setpoint)

Relay configuration

Latching or non-latching

Relay inhibit

Inhibits relay operation during start-up or machine maintenance

Input power

110V or 220V AC

Transducer types

4033-400 (Velocity)

Frequency range: 20 to 1,500 Hz
Operating temperature: -20 to +400F (-29 to +204C)

4033-500 (Velocity)

Frequency range: 20 to 1,500 Hz
Operating temperature: -20 to +500F (-29 to +260C)

4034 (Velocity)

Frequency range: 12 to 1,000 Hz
Operating temperature: -30 to +160F (-34 to +71C)

4071A (Acceleration)

Frequency range: 2.1 to 3,500 Hz
Operating temperature: -58 to +180F (-50 to +82C)

4073 (Acceleration)

Frequency range: 0.8 to 10,000 Hz
Operating temperature: -65 to +250F (-54 to +121C)

User Benefits

  • Broad-Range Protection
    Provides vibration protection across a wide range of frequencies by detecting imbalance, misalignment, bad bearings and other machinery-related problems.
  • Vibration Level Setpoints
    Two relays are included which activate when each of two Customer-specified vibration levels are reached. These relays can be connected to devices to provide visual, audible or external relay activation when the vibration limit has been reached or exceeded. The higher vibration level selected is often used to shut down the rotating equipment to avoid its damage.
  • Convenience
    Only the transducer is mounted at the point of measuring the vibration, the Electronics Enclosure is located remotely for easy access.


  • LED Display
    The 3-digit LED provides continuous indication of vibration level. Alarm and Trip LEDs energize when setpoints have been exceeded.
  • AC Output
    Provides buffered vibration signal for easy interface with analyzers and other devices.
  • Remote Transducers
    Allows you to choose the transducer that will best suit your most demanding applications. The 4034 has a low price, with high output and a wide frequency response. The 4033 transducers are well suited to high temperature mountings. The 4071A and 4073 both provide wide frequency ranges, ideal for both slow and high speed equipment.