2. Wiring and Connection
2 - 46
2-11-3 Example of emergency stop circuit
(1) Outline of function
The power supply unit's external emergency stop can be validated by wiring to the CN23 connector,
and setting the parameters and rotary switch. If the emergency stop cannot be processed and the
external contractor cannot be shut off (due to a fault) by the CNC unit, the external contactor can be
shut off by the power supply unit instead of the CNC. At this time, the spindle motor will coast and
the servomotor will stop with the dynamic brakes.
EN60204-1 Category 1 can be basically complied with by installing the external emergency stop
switch and contactor.
CAUTION
1. The power supply unit external emergency stop function is a function that
assists the NC emergency stop.
2. The emergency stop signal input to the CNC side cannot be used as a
substitute for the external emergency stop function (CN23).
3. It will take 30 seconds for the external contactor to function after the
emergency stop is input to CN23. (This time is fixed.)
(2) Example of emergency stop circuit
The emergency stop is a signal used to
stop the machine in an emergency. This
is connected to the CNC unit. Wire to the
power supply unit when necessary.
The servo/spindle unit will be decelerated
and controlled by the software according
to the deceleration stop command issued
from the CNC unit.
The diagram on the right shows an
example of the emergency stop circuit
(EN60204-1 Category 0 stop) in which an
off delay timer (TM1) is installed as a
power shutoff method independent from
the NC emergency stop input. The
required safety category may be high
depending on the machine and the Safety Standards may not be met. Thus, always pay special
attention when selecting the parts and designing the circuit.
Setting the off delay timer (TM1) time
Set the TM1 operation time so that it functions after it has been confirmed that all axes have
stopped.
If the set time is too short, the spindle motor will coast to a stop.
tm
≥ All axes stop time
Provide a mechanism that shuts off the power even if the CNC system fails.
POINT
Stop Categories in EN60204-1
• Category 0: The power is instantly shut off using machine parts.
• Category 1: The drive section is stopped with the control (hardware/software
or communication network), and then the power is instantly shut
off using machine parts.
(Caution) Refer to the Standards for details.
Refer to Section 9.2.5.4.2 in EN60204-1: Safety of Machinery
Electrical Equipment of Machines – Part 1.
GND
R
R
GND
External
Emergency
Switch
TM1
RA1
MBR*
EMG
CUP
&
ASIC
SV1/2
CN23
Hardware Emergency
Software Emergency
NC Unit
Power Supply
Unit
Servo/Spindle
Drive Unit
CN1A/B
CUP
&
ASIC
CUP
&
ASIC
MC-OFF*
MC1
L1
L2
L3
L21
L11
CN4
CN4
CN20
MBR*
Motor
Brake
AC Reactor
External
Contactor
MC
L21
L11
P
N
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