Siemens PLC analog input
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Why do some analog input cards display the maximum value when the external connection is disconnected, while others show the minimum value for the corresponding analog signal after the connection is broken? ?
I remember that if the wire in a loop is too short, the value becomes the minimum, which is -32768. But it seems that it can be set in some hardware properties of the card.
Resistance signal: when the connection is broken, the resistance is at its maximum
It’s not a resistance card; it’s a card that accepts 4-20mA signals
It’s a circuit break. Do you mean that it’s possible to adjust through hardware settings to maximize or minimize the numbness level? ?
The maximum or minimum value is determined by the process requirements!
I remember it’s the value output at the last moment; it’s not necessarily the maximum or minimum, right?
This is the display result after a connection is lost; it is set in the DCS software, and one can choose to have the value at its maximum, minimum, or unchanged.
Original poster, regarding this issue, it depends on whether you need the maximum or minimum value when the connection is severed; it’s related to your alarm and safety requirements. The rest are issues related to settings.
It’s a Siemens PLC, not a DCS