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What are the basic differences, advantages and disadvantages, between controller using 4ma-20ma system and 0-10v system.
19/07/2011 A: Klaus Hense, Grabner Instruments messtechnik GmbH, klaus.hense@ametek.at
4-20 mA has two advantages compared to 0-10 V:
1) if the connection breaks, you will immediately see 0mA, which is obviously a fault condition that can be easy recognized.
2) The transition is not influenced by cable resistance - if you have long cables, than you will have a measurable voltage drop on the cable - the current of the 4-20mA device will be still 4mA (as long as the resistance of the cable does not increase beside the value where the device can not drive the current).