Duo Alta | Rope Slack and Gripper (Safety Device) Test
The safety devices fitted to the lift are to be tested in the order given.
- Leave the lift and close the door. The light should turn off automatically after 20 seconds.
- Comment; the rope slack limit test is connected so it is ‘fail safe’ meaning this switch is always monitoring that there is tension on the ropes. This is done by the action of the striker which is positioned on the back of the motor holding the switch closed.
- Relay TR is controlled by the safety line of the PLC program. Relay TR is controlled by the rope slack limit. Relay TR and Output 8 of the PLC will turn off if this limit is not engaged.
- Testing the action of the grippers will make the rope slack. Relay TR will ‘turn off’, and it has an LED on the front face of the relay. ‘Please identify’ it on the front of the electrics panel.
- Ensure the lift cab is free of all payload. Rope slack and gripper testing must be carried out on an empty lift cab. Any payload in the lift at time of testing could lead to internal damage to mechanical parts inside the hoist unit.
- First, test the left-hand lift rope. Grasp the wire rope (we recommend using gloves) and pull the rope toward the middle of the lift i.e. away from the guide rails. The lift will raise a little as you do this. When the rope is approx. 300 – 400mm (12″ – 16″) away from the guide rails quickly release but do not let go of the rope. The gripper will grip the rod and the rope will become slack.
- The left side gripper plate is now holding the weight of the lift (as it should). Now TR relay (green light) will be switched ‘off’. This means there will be no power to the motor drive unit – this is correct.
- To reset the gripper plate (first), slowly pull out the cable again until the lift starts to raise then you will hear a click which is the sound of the gripper dropping back into position. Now ‘slowly release the rope’. The lift is now hanging on the ropes again.
- To reset the hoist (second), and re-establish power to the motor drive unit, you will need access to the remote pendant controller (green cat5 connection) or key switch in the cab c.o.p. or electrical panel circuit breakers (CB1 and CB2). Turn the switch ‘off’ and then back ‘on’. Relay TR will now be ‘on’.
- Repeat the above steps 6 to 9 for the right-hand lift rope.
Important; ensure care is taken for steps 5-10, make sure everyone is clear and safe.