Some of the mechanical instrumentation required updating. Installing transmitters and analog PLC was cost prohibitive. The customer evaluated UE’s ONE Series Electronic Switch and decided to replace the mechanical switches with electronic ones. The ONE Series electronic switch specifically models (All-in-ONE) were selected for the following reasons:

• The ONE Series had 6 times better accuracy than a mechanical switch. In addition, the temperature model was fitted with a pt100 RTD, which is highly sensitive and accurate compared to the typical fluid-filled sensing element used in mechanical switches.
• Both ONE Series models were integrated with device diagnostics that could indicate whether it was functioning. The devices also had a diagnostic output that could be remotely transmitted to the DCS so that the operator would know when the electronic switch was faulty and immediately troubleshoot it.
• The electronic switches require minimal commissioning and maintenance as the set points and dead bands are field programmable, saving more than 70% in maintenance time compared to a mechanical switch. The 1XSWLL model operates on the same 2 wires as a mechanical switch enabling replacement of the mechanical switch without rewiring or reprogram the PLC.
• The multi-function 1XTXSW loop powered hybrid transmitter with 2 solid state relays enabled the user to extract the 4-20 mA signal to monitor the temperature trending in the host system and simultaneously use the relay output to activate the beacon on the roof of the shelter in event of high temperature. A single 1XTXSW was able to perform the task of a transmitter, two switches and a gauge simplifying instrumentation and helping the customer to streamline instrumentation inventory.