nifty TM Series Operating And Safety Instructions Manual page 31

4.5.4 CALIBRATION
If a closer examination of the system is required, typically for testing and approval, the safe working
load should be placed in the cage, carefully weighing the test load to ensure accuracy. The addition of
a 5kg weight, to any of the four corners of the cage, should sound the alarm. If the alarm does not
sound, carefully inspect the weigh mechanism for signs of damage. All parts of the weigh mechanism
should be free to move, and the inspection should look for any impact damage that might have caused
the assembly to become disabled, for any reason. If the mechanism seems to be functioning correctly,
the adjustment of the weigh sensing micro-switch should be checked. A competent person, who has
the authority to perform such adjustments, must perform this. Adjustment must not be permitted by
anyone without the approval of the person responsible for the platform.
With the machine emergency stops 'enabled' and either the cage or base key switches turned 'On', the
cage weigh micro switch is adjusted to bring the bolt into contact with the micro-switch roller.
Continue adjustment until the alarm sounds, then back off slightly to silence the alarm. The locknuts
supporting the adjustment bolt can be partially tightened to lock the bolt in place.
The addition of a 5 kg weight should now be used to prove that the system detects the applied
overload, sounds the alarm and disables the machine. The sensitivity of the assembly is such that the
alarm will sound slightly before the functions are disabled. The mechanism should be adjusted to
allow the alarm to sound and functions to be lost within this 5 kg limit. Lock the adjustment screw
securely.
The over-travel adjusters can now be used to protect the micro-switch from excess forces should a
substantial overload be applied to the cage. (Typically if the machine is manoeuvred into contact with
a fixed object, snagging the cage assembly, this would be detected as an overload to the system.)
Adjust the screws forward until they come into contact with the cage weigh mechanism, then with the
cage overload still applied and the alarm sounding, functions disabled and machine not operating, lock
them in this position. Care should be taken to not turn the adjuster screws in too far; otherwise the
overload signal might be lost.
The machine can then have the overload removed and the functions of the machine checked for correct
operation.
4.5.5 INSPECTION
The cage weigh system is controlled through the detection printed circuit board, part number P16164.
This PCB is connected directly to the safety micro-switch and monitors the function of the cage weigh
system. The two relays are configured such that both need to operate to permit safe operation of the
assembly. Should either of them fail, an error signal is generated which can be seen on the printed
circuit board itself. This occurs if pressing the green button does not allow the machine to operate, no
overload signal to be given, with no load in the cage. In this case, open the cage pushbutton box or
separate box containing the PCB and look at the printed circuit board.
There are three LED's (Light Emitting Diodes) on the board, Red LD1 for 'Overload', Red LD2 for 'Relay
1/2 failed' and Green LD3 for 'Machine enable'. The first indicates the overload when the machine is
turned 'On', the second indicates a relay failure when the green button is pressed, and the third shows
the machine is enabled, again when the green button is pressed.
English/USA – 01/10
Issue 06
Operating & Safety Instructions
TM Series
29