44
Synchronization to an external signal is unreliable:
Verify that the pulse width of the external trigger pulse is at least 1
μ
s long. Use
an oscilloscope with a high impedance input to monitor the external signal while
it is connected to the Chopper Controller. The input signal should have valid
TTL voltage levels.
Motor oscillates wildly:
Recall the factory default settings. This will place the instrument into known
conditions. If the oscillation stops, then the signal supplied via
Sync In
may have
been unstable. Verify the stability of the input signal with an oscilloscope or
frequency counter. The frequency of the signal on
Sync In
may have been
outside of operating limits which are determined by the operating
Mode
,
H
,
S
,
and the
Wheel
setting. Refer to the entry on the FREQ setting in Section 3.5.1 on
page 24 for more details.
Observe the signal at
F
outer
on an oscilloscope. If the cable or optical sensor is
damaged, the signal will remain high or low. If this is the case, replace the cable
between the Chopper Controller and the Chopper Head.
Check for the correct wheel setting on the front panel.
