Festo Контроллеры двигателя CMMS-ST - Manual (Page 86)

4. Functional safety engineering
86 Festo.P.BE-CMMS-ST-G2-HW-EN 1008NH
4.2.4 Explanations of the sample circuit
The circuitry example shows a combination of the CMMS-ST-G2 with a PILZ PNOZ X2P
safety switch device. An emergency stop in combination with a protective door is drawn as
a switch device. In total, three logic elements can be switched in series. A door position
switch can also be used that keeps the protective door closed until the drive has stopped
or the “Driver supply acknowledgment” signal indicates a safe state and the plausibility
check is successful.
Technical data, such as max. current, etc. can be found in the data sheet of the safety
switch devices.
4.2.5 EMERGENCY STOP request, monitoring of protective
doors
After the Emergency Stop is actuated or the protective doors are opened, the two normally
open contacts of K1(13, 14 and 23, 24) open immediately. This results in the immediate
removal of the end-stage enable and disconnection of the driver supply via [X3] Pin 2. The
unintended opening of the protective doors must be prevented in the system.
Approx. 80 ms after opening of the PNOZ contacts for switching off the driver supply, the
acknowledgment contact ([X3], Pin 5 and 6) is closed.
At least 30 ms after the potential-free acknowledgment contact closes, an “H” is displayed
on the 7-segment display of the controller to indicate a “Safe standstill”.
Due to the drawn circuitry, a two-channel operation with cross-circuiting recognition is
possible. This permits recognition of:
• Earth faults in the start and initial circuit
• Short circuits in the initial circuit / start circuit
• Cross circuits in the initial circuit.
Removal of the end-stage enable and switching off the driver supply via [X3] Pin 2 causes
the drive to run out.
4.2.6 Testing the safety function
For each on-off cycle of the machine, the PILZ device PNOZ X2P checks whether the relays
of the safety equipment open and close properly.
The function of switching off the output stage enable must be checked regularly (e.g.
monthly) via the PLC.