Metrix 440 Internal/External Sensor

Provides local contacts as well as a 4-20mA output for interface with a PLC / DCS or other process monitor. Precaution: Placing the switch inside the cooling tower can cause the seal to fail if the moisture inside the tower contains corrosive substances.

Metrix 440 and 450 electronic vibration switches provide eco-nomical, self-contained, single-channel vibration protection. The 440 switch is suitable for use in non-hazardous as well as Class I Div 2 hazardous areas. The 450 switch utilizes the same internal electronics as the 440, but features explosion-proof enclosure styles suitable for Class I Div 1, Class II Div II, and Class III hazardous areas.

Options are available for electronic (triac or FET) or electro-mechanical relay outputs, allowing the switch to be used in an auto-shutdown circuit that trips the machine under high vibration conditions. SR versions provide a single alarm setpoint and corresponding discrete output. DR versions provide two independent alarm setpoints and corresponding discrete outputs, allowing implementation of ALERT (pre-shutdown) and DANGER (shutdown) levels.

A separate 4-20 mA proportional output is also provided on all switch models, allowing connection to PLCs, DCSs, strip chart recorders, or other process control systems where vibration levels can be trended.

Vibration on both switches is monitored in RMS velocity units. The standard configuration consists of an internal accelerometer mounted inside the switch housing, providing completely self-contained functionality. The switch may also be configured to use an external accelerometer if desired.*

Model: 440

The electronic switch utilizes a solid state crystal accelerometer which provides an electrical output when it is deformed by the vibration forces. The output is electronically converted to a signal proportional to velocity. This signal is compared with a preset limit and triggers a solid state relay if the limit is exceeded. There are no moving parts in the 440 vibration switches except when configured with mechanical relays.

An important feature of the switch is the built-in time delay. This prevents triggering of the alarm or shutdown functions from transient increases in vibration levels. It also avoids shutdown due to transitory vibrations occurring during start-up.
Almost all machines experience a few seconds of high vibration during start-up before reaching operating speed. When no time delay function is included, as with mechanical switches, this start-up vibration causes a trip. Frequently, the operator turns the trip setting up until he can get through start-up. The resultant trip level is too high to afford protection at the machine’s operating speed.
Three-second alarm trip delay is standard on the switch. Alarm time delays are independently adjustable in the field over a range of 2 to 15 seconds.
Product Aprox. Weight: 1.6 kg (3.5 lbs)

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Metrix 440 Internal Sensor Datasheet
Metrix 440 Internal Sensor Manual