from the Operation department...
Voltage and current signal to PLC
Information resources, documentation. topic
Posted by M.Aizam on 15 August, 2003 - 12:19 am
Need some ideas, how to measure voltage and current through simple DC motor circuit using analog transmitter to Mitsubishi PLC (FX1s or FX1).

Posted by Steve Todd on 17 August, 2003 - 5:40 pm

Moore Industries offers a wide variety of signal transmitters, isolators and converters for this type of application. Information can be found at:

Steve Todd

Posted by Oscar on 18 August, 2003 - 1:13 pm
Check the hardware twice, as far as my knoledge FX series are onlu Input/output able, there's no way to get other signals than 24 volts. Please check it out.


Posted by Steve Myres, PE on 18 August, 2003 - 1:19 pm
Connect the voltage to a signal conditioner/isolator, thereby reducing from a likely range of 0-100 or 0-200 volts to a range the PLC can accept, such as 0-10V, as well as isolating it. If the PLC input is internally isolated, divide the voltage with resistors. For current, insert a shunt from Empro or similar. This is a very low value resistor that will create 50 or 100mv of drop at rated current. Your PLC may have an internally isolated input module capable of accepting this range directly. If not use a signal conditioner/isolator from Phoenix or similar and send a 0-10V or 4-20ma signal to the PLC.

Posted by Anonymous on 18 August, 2003 - 1:23 pm
I can assist you. Please give me hardware specs and you will be up and going shortly.

Posted by Michael Griffin on 18 August, 2003 - 2:03 pm
To measure current, you could use either a current shunt and signal conditioner, or a hall effect transducer (e.g. LEM). To measure voltage, you need a signal conditioner. The signal conditioners will isolate and re-scale the signals. Both of these signals can go to analogue inputs on your PLC.


Michael Griffin
London, Ont. Canada

Your use of this site is subject to the terms and conditions set forth under Legal Notices and the Privacy Policy. Please read those terms and conditions carefully. Subject to the rights expressly reserved to others under Legal Notices, the content of this site and the compilation thereof is © 1999-2014 Nerds in Control, LLC. All rights reserved.

Users of this site are benefiting from open source technologies, including PHP, MySQL and Apache. Be happy.

H. L. Mencken's Law:
Those who can -- do.
Those who can't -- teach.

Martin's Extension:
Those who cannot teach -- administrate.
Advertise here
our advertisers
Help keep our servers running...
Patronize our advertisers!
Visit our Post Archive