0008 Spindle Stop Zero speed detector
Sheet 4 plug 2 pin-j
The 0008 alarm indicates a loss of the 24 volt signal through the 'zero speed detector' relay to the control interface. It will occur if the spindle is manually rotated above a speed of approximately 40 rpm in the high range, 13 rpm medium range or 4 rpm in the low gear range.

a) If the machine powers-up correctly following the alarm check the setting of the zero speed detector. Remove the lower cover of the Shackleton unit and swing-out the detector rack. The zero speed detector is the second board from the left and the relay is controlled by potentiometer 2 on the facia. Manually programme S.10 and M.03, the relay contacts on the board should open as the spindle starts. Rotate the spindle override switch slowly to 50% and adjust pot. 2 to close the relay at 5 rpm and open at 6 rpm. This is an approximate setting; the correct procedure is explained in the commissioning manual. While the relay is closed there should be 24 volts on terminal 430 in the 'power distribution panel'. If there's no 24 volts, the detector board is faulty, or if fitted, the ZSR relay in the PDP. The ZSR relay can be exchanged with the SCR relay to test.

b) Another 0008 alarm cause is spindle 'overshoot' after braking, when the spindle decelerates but doesn't stop correctly, and the voltage generated by the tacho-generator re-opens the detector relay. Spindle overshoot may be corrected by slightly increasing the 'proportionate gain' on the '3 phase control board' in the master stack of the Shackleton drive unit. The gain potentiometer is normally set at about 50%. The setting of the 'up rate' and 'down rate' pots. on the same board will also affect the spindle braking.

c) If the 0008 alarm prevents the machine from powering-up, fit a temporary wire link between terminals 400 and 430 in the PDP. A repeated 0008 alarm on power-up would then indicate a control fault; refer to paragraph (d). If the machine powers-up with the link in place, it would suggest a fault with the detector board, or the ZSR relay (if fitted) as indicated in paragraph (a). Remove the link when the fault is traced. 

d) 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 0008 alarm returns, the fault may be with the 'Watchdog' board (WD50x) 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).