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Festo — CPX-AP-A — 2022-07
Diagnostics
10.4
Load voltage monitoring
The load voltage monitoring distinguishes between "undervoltage/overvoltage PL" and "shutdown
PL". The distinction between "undervoltage PL" and "shutdown PL" is helpful if a deliberate shut-
down, e.g. emergency stop, should not trigger an error message in the higher-order controller. A
critical undervoltage, e.g. due to an excessively high voltage drop in the cable, is always reported as
an error.
A "switch off PL" is detected by the module if the load supply PL falls below the permissible tolerance
range and then drops to a residual voltage of
.
5 V within 250 ms.
The behaviour of the load supply monitoring can be set with the "diagnostics undervoltage load
supply" parameter.
The diagnostics are displayed as a combination of the LED displays [MD] and [PL] and a diagnostics
message is generated depending on the parameter setting.
Load voltage monitoring – inactive (0)
LED [MD]
LED [PL]
Meaning
Diagnostics
green light
green light
Permissible voltage range
–
green light
flashing red
Overvoltage PL
–
green light
flashing red
Undervoltage PL
–
green light
flashing green
Switch off PL
–
Tab. 22: Load voltage monitoring - inactive (0)
