Posted by: Harold Ennulat | January 26, 2010

Analog Signals: 4-20 mA or 0-10 VDC ?

Every instrument engineer has an opinion about this topic.  There is a discussion going on at LinkedIn’s Automation.com group that I found of interest.

The general consensus is that 4-20 mA signalling is preferred, (my own bias as well).  This is considered to be the most noise immune.

There are some interesting comments about the convenience of 0-10 and +- 10 VDC signalling.  One comment also notes that strain gauge and thermocouple signals for example can be run successfully at long distances even in noisy environments.

The use of differential 0-10 VDC  has so far not been discussed or compared with 4-20 mA signalling. 

When I get a choice I will choose a 4-20 mA signal.  However drive applications all seem to run on 0-10 or +-10 VDC in reversing applications when analog signalling is used.  In fact I had a colleague change all my 4-20 mA drive tension feedback signals over to 0-10 VDC because this was considered the “standard”.

Joining LinkedIn may be required to join the group and view the linked discussion.

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