During the process of updating the hardware on a customer’s existing automation system, one of AWC’s application engineers came across differences in how the S7-1200, S7-1500, and ET200SP platforms each report the measured value representation of a wire break:
- By default, the S7-1200 reports the measured value of a broken wire as 327671
- By default, the S7-1500 reports the measured value of a broken wire as -327672
- By default, the ET200SP reports the measured value of a broken wire as -327683
In addition to these differences in measured values, different types of diagnostics are available for selection at the analog module level as well. In order to keep measured values consistent across multiple PLC platforms, make sure to enable wire break diagnostics for each analog input channel that is being utilized by checking the appropriate option in the module properties and downloading the updated hardware configuration. Wire break diagnostics are NOT enabled by default! Below is an example of how to enable such diagnostics for an S7-1200 analog input module:
Additional Contributions
- Julyann Tu – AWC, Inc.
