Cause:

• An air leak/break in the piping.
• The solenoid bulb has failed.
• Wire breakage on the hand signal line.
• Hand signal line short circuit
• The hand IF card has failed or has been inserted incorrectly.
• Sink/source setting error.
• Hand connecting wire error
• Insufficient air pressure.
• A foreign material has got stuck in the air hose.
• Faulty connection in the cables that run between devices.

Measures:

• Carry out a check on the air hose, joints, air pressure, and connecting wire.
• Check the condition of the hand input/output signal.
• Check whether or not the controller's sink/source settings and wiring are consistent with each other.
• Check the condition of the connections on the cables that run between devices.