Festo Контроллер двигателя CMMD-AS - Manual (Page 89)

4. Functional safety engineering
Festo P.BE-CMMD-AS-HW-EN 1002NH 89
The switch-off delay tv takes off as soon as a standstill is recognised by the motor
controller.
Description of the timing diagram
This timing diagram was made based on the example of speed adjustment using the
controller enable DIN 5 at [X1.1/2]. For Fieldbus applications, the controller enable is
additionally controlled via the respective Fieldbus. Depending on the application, the
operating mode is also parameterisable via the parameterising software.
Initial state
- The 24 V supply is switched on and the intermediate
circuit is charged.
- The servo controller is in the "Safe halt" status.
This status is indicated by a flashing "H" on the
7-segment display.
In order to switch the servo controller end stage active once more, and thus operate the
connected motor, the following steps must occur:
1. Activation of the relay for switching the supply voltage of the end stage driver
(2 nd switch-off path) occurs at time t1 via [X3.1/2] with 24 V between pin 2 and pin 3.
2. The driver supply is then charged.
3. The potential-free acknowledgment contact ([X3.1/2] pins 5 and 6) for plausibility
checking of the relay activation opens a maximum of 20 ms after t1 (t2 – t1) and the
driver supply is switched off.
4. Approx. 10 ms after the acknowledgment contact opens, the "H" on the display goes
out at time t3.
5. The time for the output stage enable ([X1.1/2], DIN4) is selectable (t4 – t1). The enable
may occur at the same time as the relay is activated, but it must occur approx.10 µs
(t5 – t4) before the rising edge of the controller enable ([X1.1/2], DIN5), depending on
the application.
6. The rising edge of the controller enable at time t5 releases the motor holding brake
(if present) and the end stage enable occurs. The brake can only be released when the
relay for switching the driver supply is engaged, since this controls a MOSFET in the
holding brake circuit. Using the parametrising software, a travel start delay time
(t6 – t5) can be set that regulates the drive at a speed of "0" for the specified time
and, after this delay, causes it to move at the set speed at time t6. The travel start
delay time is set to ensure that the brake has actually released before motion begins.
For motors without a holding brake, this time can be set to 0.
7. At time t7 the drive has reached the set speed. The requires ramp settings can be
parameterised using the FCT parameterising software.