Festo CMMS-AS-C4-3A User Manual

4. Functional safety engineering
76 Festo P.BE-CMMS-AS-HW-EN en 0708NH
2. Switch-off path:
Interruption of the supply for the six end stage IGBTs via[X3] using a
relay (the IGBT optocoupler drivers are removed from the power
supply via a relay, thus preventing the PWM signals from reaching
the IGBTs).
A plausibility check between the relay control for the end stage
driver supply and the monitoring of the driver supply is performed
by the microprocessor. This is used for error detection of the pulse
blocker and also for suppressing error messages occurring in nor-
mal operation
E 05-2 ("Driver supply undervoltage").
Potential-free feed-
back contact:
The integrated "Safe standstill" circuitry also has a potential-free
feedback contact ([X3] Pins 5 and 6) for the existence of the driver
supply. This is a normally closed contact. It must be connected to
(e.g.) the higher level control system. At suitable intervals (e.g. PLC
cycle time or at every "Safe standstill" request), the PLC must per-
form a plausibility check between the relay control for the driver
supply and the feedback contact (contact open = driver supply pre-
sent).
If an error occurs in the plausibility check, the control system must
prevent further operation by (e.g.) removing the controller enable or
switching off the mains circuit breaker.
4.2.2 Secure stopping brake control
When "Safe standstill" is activated, power is removed from the holding brake via two
channels (brake engaged); (see block schematic).
1. Channel
The holding brake is controlled by DIN5 (controller enable) in nor-
mal operation (see following timing diagram). The 1st "end stage
enable" switch-off path affects the brake driver via the microproc-
essor and removes power from the holding brake (brake applied).
2. Channel
The 2nd "Relay control for driver supply" switch-off path directly
controls a MOSFET that activates the holding brake (brake applied).
Caution
The user is responsible for the dimensioning and the reliable func-
tioning of the holding brake. The functioning of the brake must be
ensured via a suitable braking test.

Festo CMMS-AS-C4-3A Specifications

General

Brand	Festo
Model	CMMS-AS-C4-3A
Category	Controller
Language	English