Challenge: Measure inlet and outlet temperature of a process heater using existing three-wire RTDs and provide a 4-20mA process variable signal, representing the differential temperature across the heater, to a local alarm trip for heater protection and share that differential temperature signal with the Basic Process Control System (BPCS). The measurements are in a hazardous area and plant standards require the use of a certified IS system.

Problem: When sharing one Process Variable (PV) with multiple systems, the connection needs to be thought out carefully. Creating a series connection for the 4-20mA signal is not a best practice for sharing the PV, see Figure 1. The main problem in creating a series connection is when either the DCS or the PLC input is disconnected, intentionally or by accident, both the DCS and the PLC will lose the PV signal.

The ECT-DIN series dual 4-20mA output can be provided with a modified input to accept a 0-2Vdc signal. Moore Industries offers a build option from the factory (the ECT which acts as a Splitter).  The model number for an ECT with this configuration is ECT/0-2V/2X4-20MA/24DC [DIN]. Typical installation of an ECT is a DIN mount so the housing we offer is a DIN-style housing which mounts on 32mm G-type (EN50035) and 35mm Top Hat (EN50022) rails.

The THZ3 and TDZ3 Dual Input Smart HART transmitters simplify your operations with two sensor inputs, and advanced features that give you far more control over your temperature measurements. Each sensor is individually selectable and programmable via HART or DTM.

Moore Industries introduces the new universal SLD PC-Programmable Functional Safety Loop Display. The SLD features a large integral display that shows real-time process status in mA, percent, or any designated 5-character Engineering units (EGU). As part of Moore Industries’ FS Functional Safety Series products, the SLD is certified by exida as a SIL3 capable, non-interfering device for use in a safety loop.

The Problem

A pulp and paper mill had a black liquor BMS (Burner Management System) that per NFPA 85 requires that its safety logic system be totally independent from other logic systems.  The challenge was they required that key temperature and pressure signals also get monitored and recorded by their BPCS (Basic Process Control System).