Pneumatic Circuit - SMC Networks C96N C Series Operation Manual

Design the machinery to avoid such dangers.

2-8. Pneumatic circuit

W a r n i n g
① Use the pneumatic circuit which applies balance pressure to the both sides of the piston when
locking.
To prevent sudden extension when operation restarts or lock is released, control the cylinder to make
balancing pressure applied to both sides of the piston so that the force generated in the operating direction of
the piston due to load can be counteracted.
② Effective area of the lock release solenoid valve shall be more than 50% of that of the cylinder
actuating solenoid valve. The lock release solenoid valve should be installed closer to the cylinder
than the solenoid valve actuating the cylinder.
If the effective area of the lock release solenoid valve is small, or the solenoid valve is far from the cylinder, it
takes longer to exhaust lock release air and may cause locking delay. Due to the delay, the increase of
overrun for intermediate stop or emergency stop in the middle of operation can result. In applications of
holding as drop prevention, due to the locking delay, the work piece may fall temporarily depending on the
timing of the load.
③ Back flow of the exhaust pressure from the common exhaust type valve manifold is not allowed.
If exhaust pressure for lock release flows backwards, locking may not be performed correctly. Use an
individual exhaust type manifold or single unit valve.
④ Time between locking and lock release shall be 0.5 seconds or longer.
If locking time is short, the piston rod and the workload will shoot out faster than the speed controlled by speed
controller.
⑤ Control the switching operation of the lock release solenoid valve during restart of the cylinder so
that the lock release solenoid valve is switched before the cylinder actuating solenoid valve or both
switched at the same time.
If locking time is short, the piston rod and the workload will shoot out faster than the speed controlled by the
speed controller.
⑥ Be aware that repeated supply and exhaust of the solenoid valve for lock may cause condensation.
The lock unit operating stroke is very small and so the pipe is long. If supplying and exhausting air repeatedly,
condensation which occurs by adiabatic expansion, accumulates in the lock unit. This may cause air leakage
and an unlocking malfunction due to corrosion of internal parts.
⑦ Basic Circuit
1. [Horizontal]
2. [Vertical]
[Load applied in extending direction of the rod]
SOL.A SOL.B
ON ON
OFF OFF
ON OFF
ON ON
ON OFF
OFF OFF
ON OFF
ON OFF
［Load applied in retracting direction of the rod］
- 14 -
SOL.C Operation
OFF Forward
0.5S or
OFF Lock
longer
OFF Unlock
0~0.5S
OFF Forward
ON Retract
0.5S or
OFF Lock
longer
OFF Unlock
0~0.5S
ON Retract