SMC Networks LECSN-T Series User Manual

10. CHARACTERISTICS
10 - 5
10.3 Dynamic lock characteristics
CAUTION
The coasting distance is a theoretically calculated value which ignores the running
load such as friction. The calculated value will be longer than the actual distance.
If an enough braking distance is not provided, a moving part may crash into the
stroke end, which is very dangerous. Install the anti-crash mechanism such as an
air lock or an electric/mechanical stopper such as a shock absorber to reduce the
shock of moving parts.
POINT
Do not use dynamic lock to stop in a normal operation as it is the function to stop
in emergency.
For a machine operating at the recommended load to motor inertia ratio or less,
the estimated number of usage times of the dynamic lock is 1000 times while the
machine decelerates from the rated speed to a stop once in 10 minutes.
Be sure to enable EM1 (Forced stop 1) after servo motor stops when using EM1
(Forced stop 1) frequently in other than emergency.
Servo motors for LECSN
□
-T
□
may have the different coasting distance from
that of the previous model.
The electronic dynamic lock operates in the initial state for the servo motors of
400 W or smaller capacity. The time constant "τ" for the electronic dynamic lock
will be shorter than that of normal dynamic lock. Therefore, coasting distance will
be longer than that of normal dynamic lock. For how to set the electronic
dynamic lock, refer to [Pr. PF06] and [Pr. PF12].
10.3.1 Dynamic lock operation
(1) Calculation of coasting distance
Fig. 10.3 shows the pattern in which the servo motor comes to a stop when the dynamic lock is
operated. Use equation 10.2 to calculate an approximate coasting distance to a stop. The dynamic
lock time constant τ varies with the servo motor and machine operation speeds. (Refer to (2) of this
section.)
A working part generally has a friction force. Therefore, actual coasting distance will be shorter than
a maximum coasting distance calculated with the following equation.
V
0
OFF
ON
Machine speed
t
e
Time
EM1 (Forced stop 1)
Dynamic brake
time constant
Fig. 10.3 Dynamic lock operation diagram
L
max
=
60
V
0
•
t
e
+
J
M
1 +
J
L
··························································································· (10.2)

SMC Networks LECSN-T Series Specifications

General

Brand	SMC Networks
Model	LECSN-T Series
Category	Controller
Language	English