Littelfuse's MPS-OPI is a motor protection system that monitors voltage, current, and temperature to provide a total of 22 protective functions for motor protection. The system is modular with integrated protection, motor control, metering, and data logging. While the MPS-OPI is designed to be used with only one MPS-CTU Control Unit, it is possible without any sort of modification to monitor multiple Control Units because the MPS-OPI is a terminal device that does not store any type of historical data or no set-point.
Begin by connecting a two-pole switch to connect an Operator interface to a number of Controls Units.
Use either the Control Units to supply the 24-Vdc control voltage, or an independent source if you choose, but avoid switching the supply in order to prevent having to initializing the Operator Interface with each selection.
Littlefuse's technical note dictates that each Control United must be programmed with a unique identifier so that it does not trip off on an OPI loss; look under menu selection Setup/ Hardwar/ OPI/ Display/ Trip Action. Additionally multiple applications must not have OPI-address conflicts.
If you wish to issue a stop command to a motor not connected to the Operator Interface, then a stop switch must be connected to a digital input.
For more technical detail regarding the MPS-OPI visit Littelfuse.com.
By Maximilian Teodorescu
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