ABB freelance IO disconnection alarm
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How should it be configured so that an alarm is triggered when the I/O connection is lost at the upper level? Thank you, everyone
Check the relevant hardware manual; there should be an internal enable output pin
In other words, it is necessary to add diagnostic information in the IO editing, and then set alarms for the diagnostic information variables in the FBD? I wonder whether it’s possible to trigger an alarm by adding diagnostic information, or whether the alarm must be manually added in the FBD.
Answer it myself: C5 Analog Input Conversion: AI_TR function – This functional block performs analog-to-digital conversion, transforming the values of analog input variables in UINT format into digital form (real numbers). The range of the input signal is 0–20mA or 4–20mA; an error can occur only when the signal is within the 4–20MA range. If the analog input signal exceeds the allowed range, the functional block switches to a default value and sets the corresponding limit signals (SL, SH). The default value is determined based on the direction – either the previous value (DVH) or the next value (DVL) – or, depending on the configuration, the original valid value is used. To correct transmission errors, a buffer zone can be defined below 4MA and above 20MA; this buffer zone can range from 0.0% to 30% of the maximum value (20MA). Automatically apply a 50% delay to the buffer zone. If the function block detects an open circuit (input of 3.8 MA), it will generate a signal (SWB); the line detection function is active only when the signal is at 4-20 MA. System messages generated by an open circuit cannot be parameterized.