Application Notes

EAP-032132

Power line protection for 2-wire pressure transmitter

We are going to install 4 units of 2-wire pressure transmitters at field.

We plan to use single DC power supply for these multiple transmitters with parallel connection. We will install lightning surge protectors to protect each signal line. If one of the protectors fails as short circuit mode, it could cause power shutdown and stop supplying power not only to the failure loop but also to all other transmitters. We need to avoid this situation by any means. Does M-System have any solution?

We’d like you to use our lightning surge protector, model MD7ST**.

You can choose ‘Loop disconnect fuse’ type of the MD7ST with suffix code selection. When multiple transmitters are connected to single power bus, this fuse will work properly. Especially when one loop breaks as short circuit mode, this fuse blows to separate the failure loop from power bus. As a result you can avoid power down of the bus. As replacement fuse, you can use model MD7F-25.

**Surge protection: IEC 61643-21 (Categories C1, C2, D1)