E-stop and power contactor processing
The power supply of the MTX micro is switched by the integrated PLC by
means of an external power contactor. Irrespective of the processing by the
PLC, the contactor must also be reliably turned off in the event of an E-stop.
In this case, the MTX micro requires that the DC bus short-circuit (DC bus
voltage) be activated. This ensures that the energy available in the system is
used for decelerating the main spindle.
-K1
Line contactor
T
Delay time of the E-stop relay
T
Sp
Maximum braking time of the main spindle
Fig. 5-21:
Power contactor and E-stop processing
Description of processing
The drives are turned on by applying 24 V to X83.1, provided 24 V are simul‐
taneously applied to X83.2 and X86.1 (E-stop). If the 24-V voltage is removed
from X83.2 or X86.1, the drives are turned off. In this process, the CNC con‐
trols the drives to decelerate them to standstill; thereafter, the -K1 power con‐
tactor is turned off. The power contactor is additionally switched via a time-
delayed contact of the E-stop relay. The E-stop relay also activates the DC
bus short-circuit with a time delay. These measures are intended to ensure
safety in case if E-stop events.
●
The delay time of the E-stop relay must be selected such
that it is longer than the maximum braking time of the main
spindle.
●
If the main spindle motor used is not an asynchronous motor
(e.g. synchronous spindle motor), the DC bus short-circuit
may not be activated in case of E-stop events. In such a
case, please contact the Rexroth Sales Division!
DOK-MTXMIC-EASY*******-CO06-EN-P
Bosch Rexroth AG
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IndraMotion MTX micro Easy Setup for Standard Turning and Milling Machines
Selecting and connecting the hardware
