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«November 2018»

Sharing Process Variables: Quad Isolator

Sharing Process Variables: Quad Isolator

Problem: When sharing a Process Variable (PV) with multiple systems, the connection needs to be thought out carefully. Sending a signal to more than one PLC or receiving device needs to be considered just as thoughtfully.

Solution: In part 1 of this series, sharing one Process Variable (PV) was discussed. Creating a series connection for the 4-20mA signal through multiple receiving devices is not a best practice for sharing the PV signal.  When sharing a Process Variable (PV) with multiple receiving devices or PLCs, the connection needs to be thought out carefully as well. Moore Industries has a clean and simple solution for connecting a PV to multiple devices.

Figure 1. Quad Isolator Using MIX

Note: The model used is the MIX / 4X4-20MA / 4X4-20MA / 12-42DC [DIN] 

We recommend sharing the PV through a multi-channel isolator so that you can send your PV to more than one PLC. Moore Industries has multi-channel isolators, like the MIX, to help customers with their PV sharing, see Figure 1.

The MIX is a reliable and very economical 2 or 4-channel high-density loop powered signal isolator and converter.  Only 25.4mm (1 inch) wide, the MIX delivers low cost I/O at 0.25 inch (6.35mm) per channel to substantially reduce installation, panel space, and instrument costs. The 2 or 4-channel MIX can take the place of four individual 4-20mA/4-20mA isolators.

By using the 2 or 4 channel MIX you no longer have to worry about lost signals, or broken current loops, when one of the receiving devices fails or needs to be replaced.

Please feel free to contact us if you have any questions. Check out the MIX.

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Published: November 7, 2017