Technical data

30
• DOK-DIAX02-DDC01******-PRJ1-EN-E1,44 • 01.97
3. Electrical Connections - Installation Guidelines
3.13. Control Circuit in the DDC with Dynamic Braking
This control circuit should be selected if a synchronous motor, e.g., MDD, is
connected to the DDC.
Dynamic braking always brakes synchronous motors to a standstill whether
or not the drive electronics are operational. The DC bus is only short-circuited
with a drive fault.
In the event of an emergency stop (E-stop) or a disconnect, the drives are
braked to a standstill at maximum torque by the drive electronics.
If the ON button is pressed, then auxiliary relays K3 and K4 switch mains
contactor K1 on. Should K3 or K4 fail, then power cannot be switched on.
If the E-stop button is pressed, then K3 and K4 safely switch off mains
contactor K1. The NC control unit of the machine must simultaneously lock out
the drive enable (RF input with analog interface, E-STOP input of a DEA with
a DLC single axis posititioning module). The command value of the drive is
then switched to zero. There is a controlled braking of the drive.
A drive error signal from the Bb contact of the DDC, an error signal from the
controller (servo error) or an overtravelling of the limit switch disconnects the
mains contactor and triggers dynamic braking.
The signal sequence as depicted in the diagram below is recommended for
commissioning the DDC.
Application
Features
Operating principle
Input
signal
DC bus
dynamic brake
OFF
ON
UD contact
1)RF
2)CLEAR
Output
signal
1
0
1
0
1
0
1
0
1
0
E-stop
1
0
1
0
1
0
2) automatic
mode
t
1
t
2
t
2
t
2
t
3
t
3
t
3
t
4
t
4
t
4
t
4
t
4
t
3
t
5
t
5
2)START
t1 > 3 s; t2 > 100 ms; t3 > 10 ms; t4 >= 20 ms; t5 > 0.3 s
1) Drive enable signal in drives with analog interface or E-stop input in
drives with DLC positioning module.
2) Applies only to drives with DLC positioning module.
t
5
SVDDC01
t
4
t
1
t
1
t
1
Fig. 3.13: Signal path diagram for switching on a DDC