SMC Networks C96N C Series Operation Manual page 41

Reported failure
Check the lock unit
and peripheral
equipment.
Locking Malfunction
Check the cylinder
and peripheral
equipment
Check the
peripheral
equipment of the
lock unit.
Large overrun.
(Stopping accuracy is
Sudden extension of the
low)
rod when the lock is
released.
Cylinder speed changed
Changes in the load.
② Cylinder part
Reported failure
Impact applied due to high speed operation.
Damage and/or
deformation
Lateral load is applied.
Major causes
Solenoid valve for locking is de-energized, but air is
④
supplied from the solenoid valve.
No problems are confirmed in ① to ④ above, but
⑤
locking is not possible even when air is supplied to
the lock unit.
① Cylinder is too fast.
② Load weight is too large. (Load factor is too high)
Air circuit is not a recommended balanced circuit.
③
(Excessive cylinder output is applied to the lock unit)
④ Failure of the auto switch for signals for locking.
[Proximity switch for locking is installed outside of
the cylinder]
⑤
Operation range of the proximity switch is
exceeded.
Effective area of the solenoid valve for locking is too
①
small.
Piping between the lock release port and the
②
solenoid valve for locking is long or the piping
diameter is small.
③ Poor response of the solenoid valve for locking.
Poor response of the solenoid valve for locking to
④
the auto switch for signal detection.
[Proximity switch for locking is installed outside of
the cylinder]
⑤
There is a play with the switch detector of the
proximity switch. The shape of switch detector is not
suitable.
⑥ AC is used for the electric circuit.
a. The circuit is not balanced.
b. Regulator for balancing pressure is not adjusted.
c. Line pressure fluctuates.
d. After stopping by locking, it is too fast to unlock.
a. Misalignment of the piston rod and guide.
b. High load rate of the cylinder.
c. Stopping interval (pitch) is short.
d. Stopping in the middle of cushioning process or
immediately after the cushioning process. (When
air cushion type is used)
e. Line pressure fluctuates.
a. Load varies continuously due to rotating
movement.
b. Load varies due to vertical load. (Step change)
Major causes
Check the solenoid valve type if it is normal open type. Change it to normal
close type which supplies air while the valve is energized.
It is possible that the inside of the lock unit is broken. Replace the unit.
(Do not disassemble or repair. Contact SMC Sales office.)
Decrease the speed by setting the speed controller.
Confirm if the allowable kinetic energy is exceeded referring to the Selection
Graph.
Connect air by recommended balanced circuit. (Refer to Page 15)
Check the auto switch wiring and operation. Replace the auto switch if it is
broken.
・Check the operation range of the proximity switch. (Change the switch to the
auto switch with timer)
・Change to proximity with with self-holding circuit.
・Revise the installation of the proximity switch and switch detector for redesign.
Replace the solenoid valve to the one with larger effective area.
・Install the solenoid valve for locking close to the lock unit and shorten the
piping tube or, directly connect them.
・Install a rapid exhaust valve close to the lock unit piping port.
Replace the solenoid valve to the one with better response.
Replace the switch with the auto switch with better response.
・Adjust the switch detector to eliminate the play.
・Redesign the switch detector.
Change the circuit to DC type.
Change to recommended balanced circuit. (Refer to Page 15)
b. Adjust the regulator valve. Check if the locked status is balanced.
c. Install an air tank so that pressure fluctuation does not occur when supplying
air to the lock unit and cylinder.
d. After stopping by locking, release the lock after waiting for 0.5sec or longer.
a. Adjust the alignment of the piston rod and guide or use the floating joint.
b. Use a larger cylinder.
c. Set the stop interval to 40mm or wider.
d. Change the cylinder to rubber cushion type.
c. Install an air tank so that pressure fluctuation does not occur when supplying
air to the lock unit and cylinder.
a.Cylinder with lock is not suitable. Use the cylinder which use incompressible
fluid such as air-hydro cylinder.
b.When there is a step like change of the load, use a multi-stage pressure
regulating valve for balancing pressure.
・Readjust the cushion.
・Reduce the operating speed.
・Reduce the load.
・Mount an external impact absorbing mechanism. (Shock absorber, etc.)
・Provide a proper guide.
・Modify the mounting condition.
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Countermeasures
Countermeasures