EDM safety sub-function with MOVISAFE^® CS..A

The EDM (External Device Monitoring) safety sub-function diagnoses the connection of the external, safe digital outputs F-DO.. The EDM function uses one or several safe digital inputs F-DI.. to monitor external switching elements connected to a safe digital output. To that end, the auxiliary contacts of the external switching element are connected to the safe digital inputs F-DI.. of the CS..A safety option.

The EDM function permanently compares the logical output signal of the safe digital output F-DO.. with the logical input signals of the assigned safe digital inputs F-DI.

If the expected logical signals are not detected once the monitoring time has lapsed, the configured fault response is triggered and the affected safe digital output F-DO.. is disabled. If the F-DO.. has the "closed" switching state and there is a voltage present, the Operating time T_1 (8705.32) is used as the monitoring time. If the F-DO.. has the "open" switching state and there is no voltage present on the F-DO.., the Fall time T_2 (8705.33) is used as the monitoring time. The Operating time T_1 (8705.32) and Fall time T_2 (8705.33) monitoring times must be greater than the input filter time. Furthermore, the discrepancy time in the monitoring time must be taken into account for a 2-channel safe digital input. The Operating time T_1 (8705.32) and Fall time T_2 (8705.33) monitoring times should be configured to the same value. If there is an applicative need for different values, the signal can change again upon expiry of a longer period of time.

The monitoring time begins again every time that the logical F-DO signal is switched. If the auxiliary contact's signal bounces, the bouncing must be filtered out via the Input filter time (8704.2) of the F-DI.. If the F-DO.. is consistently controlled and after the monitoring time has lapsed, a level change in the input signal must trigger the execution of the error response.

Each EDM instance can be assigned 1 or 2 F-DI.. The F-DI.. must not be parameterized interlocking. The auxiliary contacts of the external switching element can be designed as an NO contact or typically as an NC contact. The user is responsible for ensuring its safety-related suitability.

• 1 auxiliary contact of type NO contact

• 1 auxiliary contact of type NC contact

• 2 auxiliary contacts of type NO contact

• 2 auxiliary contacts of type NC contact

• Activation
• Status
• Fault response