1108 Spindle Start Zero speed detector
Sheet 4 plug 2 pin-j
This error indicates a 24 volt signal from the 'zero speed detector' relay present at the control interface when there should be zero volts. It should only occur if the spindle fails to rotate when an M03 or M04 spindle start is requested.

a) Monitor the voltage at rotary switch position 19 on the 'Shackleton Drive Diagnostic Unit', If the unit isn't connected - switch-off the machine at the main isolator and plug the ribbon-cable connector onto the board in the 'Master Stack' (lower of the two) with the cable entry towards the diagnostic unit. A digital voltmeter can be plugged into the auxiliary sockets of the diagnostic unit for accurate voltage measurement. Re-apply power to the machine. If the machine shuts-down with a 1108 error the fault is likely to be a control fault, refer to paragraph (c). If the machine powers-up without errors, manually programme M19, while monitoring the voltage at test point 19. The voltage should be around zero until the spindle starts to rotate and then increase to about 150mV. If the spindle doesn't rotate, or turns very slowly and the monitored voltage doesn't exceed about 100mV, the 'speed loop zero' pot on the '3 phase control board' in the master stack of the Shackleton drive unit may need slight clockwise adjustment. Follow the procedure for the spindle drive set-up in the 'Commissioning and Service Manual'. If a 0108 error displays and the correct voltage is measured continue with paragraph (b).

b) The fault is related to the 'Zero Speed Detector' board in the Shackleton auxiliary detector rack, board number 2. Either potentiometer 2 is set too high, the relay is faulty, or there's a fault on the board. Re-apply power to the machine and programme S200 and M03. An 1108 error would suggest a faulty board or relay; if another Shackleton Drive Unit is available, of the same type, the boards can be exchanged to test. No error would indicate that pot. 2 requires adjustment: stop the spindle, turn pot. 2 fully anti-clockwise, then programme S10 and M03 with the 'Spindle Override' switch set at 50%. Slowly turn pot. 2 clockwise until an 1108 error is displayed; this is an approximate setting, but should clear the 1108 fault at spindle speeds above 6 RPM. The correct procedure for setting the zero speed detector is documented in the 'Commissioning and Service Manual'.

c) Switch-off the control and transpose the 'DI' boards situated in the lower rack to the left. Power-up the machine and retry; if a different, unrelated error displays the 'DI' board is faulty and will need replacing. If the same 1108 error returns the fault may be with the 'Watchdog' board (WD 50x) in the control or corruption of the memory. If another control is available the 'Watchdog' boards can be exchanged to test. If the memory is to be reloaded remember to punch-out programme and tool information first (although an up to date back-up tape should always be held).