AB7007/AB7072: ignoring the 5V output pins on the Serial connection


I’m using an AB7007/AB7072 to connect to Hamilton probes;

pH, Dissolved Oxygen and Viable Cell Density.

They require 24V supply but the Serial port of the AB7007/AB7072 produces only 5V.
I know it is possible to supply the probes with 24V independently but my questions are as follows;

  1. If I have nothing drawing current across pins 1 (5VOUT) and 5 (Ground) of the Serial port, will this generate an error/red LED/prevent Ethernet/Modbus comms?

  2. If an alarm is generated, can it be handled with some implementing some kind of resistive arrangement, to convince the Anybus it is connected properly?

Thanks in advance of a reply!

Kind Regards,



Our AB7072/AB7007 devices multiple serial connections. All of these operate differently, and are outline in our User manual. I would review section B4 Subnetwork of the User manual.

Our devices supply the 5 volt on to the serial connection. It is used for the serial connection, and not powering a connected device.

  1. The Anybus Communicator supplies the 5 volts on RS485/RS422.This is internal to the unit, and generates current and voltage.

  2. There is no way to bypass LED subnet 5 errors. The only way to resolve this is to diagnose the connection issues on the serial side.

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