6/8/2019 2:28 PM | |
Joined: 5/6/2010 Last visit: 9/2/2024 Posts: 1978 Rating: (276) |
Hello memoll2012, in principle is it possible to switch analog signals like 4..20 mA with relays. Important ist that you use relays for signals (with gold contacts) e.g. like this The problem is that you can't monitor the 4 mA as a live zero. regards |
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6/10/2019 7:08 PM | |
Joined: 3/28/2010 Last visit: 9/18/2024 Posts: 1056 Rating: (213) |
What happens to the device generating the 4-20mA signal when there is a temporary interruption of loop power, like happens when the loop is switched in or out by a relay? Many devices sense the loss of power an either flag and error message or, in the case of 2 wire loop powered transmitters, go through an initialization process, which can take tens of seconds to complete the 4-20mA becomes valid. See a discussion on this topic on other fora: https://control.com/thread/1467381628 http://www.plctalk.net/qanda/showthread.php?t=62457 |
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