A SNAP analog output module assigned an Upper or Lower Clamp value outside its valid output range, is forced offline. The module cycles online and offline until valid clamp values are written. Depending on the application used to view the module's readings, a '-nan' or -32768 may be reported.
The following settings for a SNAP-AOA-3, 4-20 mA module cause the problem:
Output = 4 mA
Upper Clamp = 5 mA
Lower Clamp = 50 mA← This is out of range
The following settings for a SNAP-AOV-5, 0-10 VDC output module cause the problem:
Output = 0 VDC
Upper Clamp = 0 VDC
Lower Clamp = 25 VDC← This is out of range
Additional symptoms as seen from PAC Manager's Status Read page:
- Smart Modules Present mask indicates the module is offline.
- Times Discovered for the module increases.
- Arcnet Reconfigs Detected does not show count as increasing.
The Upper and Lower Clamp values are entered in PAC Manager using this window: (Tools→Inspect, Point Config)
Likewise, the clamping limits may be entered in PAC Control:
Opto 22 is investigating this issue.