Scitec Instrument Synchroniser is a unit that allows an Optical chopper to be synchronised to an external reference signal. The chopper is both phase and frequency locked to the positive going edge of the master reference signal and the time difference (lead/lag) can be controlled via the synchroniser's USB interface.
Phase difference between the positive going edge of both the phase reference and chopper reference input signals is minimised
Phase lock typically achieved within 10 seconds over the full operating range of chopper
Phase lock mantained to within 2 degrees, 90% of the time
Relative Signal/Reference time delay in increments of 200 ns from 0 to +/- 13.1068 ms
Phase lock to multiples and sub-multiples of the Phase Reference input frequency (operating limits to be determined)
Output compatible with 300CD,310CD and 360C OEM choppers fitted with any compatible Scitec disc.
(Please specify when ordering with what Chopper and disc you need the Synchroniser configured for)
Inputs filtered with single pole roll-off at 160kHz
USB 2.0 Interface witha control application with push-button style increment/decrement/reset of time delay. Set delay values retained on next power up.
Connect the synchroniser reference input to the optical chopper reference output, the synchroniser control output to the optical chopper control input, and the synchroniser master reference signal input to the signal which the optical chopper is to synchronise with.
The inputs of the Optical Chopper Synchroniser are filtered and taken through a 74 HCT series gate with Schmitt trigger inputs. The unit will work with TTL levels or 74HC series 0-5V logic levels. Square waves with clean edges will give better synchronisation than slowly rising or noisy signals.
Avoid long periods with only either the chopper or the synchroniser powered. Also avoid a 'Unit Off' state when a reference is applied.
The recommended start up sequence is:
Set the optical Chopper to EXT. If the Optical Chopper is a Model 300CD then the manual speed control should be set fully clockwise. This is not necessary for the Model 310CD.
With the Master Reference disconnected, or switched to 0V, power up both the synchroniser and the optical chopper. Wait approximately 10 seconds for the synchroniser control loop to stabilise.
Connect or enable the Master Reference.
The control loop output from the synchroniser will be at the lowest speed setting and within 20-30 seconds will synchronise to the master reference.
It is recommended disconecting or disabling the master reference before switching off.