Basic application 39
4.3.4 Using pushbuttons for simple STOP / START (Coast to stop)
Note. This circuit will cause the contactor to drop out as soon as the STOP button contact is opened because
the START input is opened together with the RUN input, which over-rides the STOP M ODE RA MP function.
When the STOP button opens during running, the main contactor will de-energise within 100mS, and the
motor will coast to rest under the influence of external factors e.g. friction and inertia, or by using an
external dynamic braking resistor to dissipate the rotational energy.
Note. The CSTOP must be high for at least 50mS prior to START going high.
In order to allow regeneration during the stopping sequence an external latching circuit must be employed to
control the STOP / START contacts (T47 / 48 cannot be used), and the RUN input is not controlled from the
ST ART terminal. See 4.3.5 Using pushbuttons for STOP / ST ART (With ramp to stop, jog and slack take up).
See 6.5 CHA NGE PARAMETERS / STOP MO DE RA MP.
T47
LA T1
T34
C STOP
T33
START
T35
+ 24V
T46
CO N2
T45
CO N1
STOP
ST ART
CONT A CTOR
COIL SUPPLY
CO AST
ST OP.
Must be
high prior
to ST ART.
M AIN
CONT A CTOR
INTERN AL
CONT A CTS
Internal contacts + 24V coil energised
by (START or J OG) AND CSTOP
0V
T36
0 V
T32
J O G
T31
RUN
T48
LA T2
Auxiliary contact on main
contactor in series with
RUN for contactors with
ON delay > 75mS.
RC SNUBBER across
contactor coil..
Typical values are
100 Ohms 1 W and
0.1uF both rated for
the coil supply volts.
Stop mode
ramp delay.
Terminated
by RUN
going LO W
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