Hi Richard,

I also encountered the same as Sibuea. My RD150 display unit did not show up the startup screen without sensor connection even though the 24Vdc supply was connected to terminal 3 & 4.

I also have an issue with RD150 & PLC connection. In my case, I have LR250 Level Sensor for tank leveling and we use both RD150 & S7-1200 PLC system for tank level monitoring from local & control room. Individually either with RD 150 or S7-1200 PLC, the tank level can be read. But, when I tried to combine with both Sensor+RD150+PLC in loop connection, no reading can be achieved from both monitoring units. The operation manual of RD150 mentioned the possibility of PLC connection but no detail wiring diagram is shwon.

Please find the attachment and kindly advise how I shall make the wiring connection.

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Split from RD 150 Connection.