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 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.

300CD Optical ChopperFeatures

 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.

300CD Optical Chopper  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.


Universal mains (90-264 Vac, 127-375 Vdc, input frequency 47-440Hz) power input with IEC connector)

Mains input current (0.75 A at 90V, 0.35A at 230V )

Frequency Control: Internal - Manual Control via 10 turn potentiometer. External - BNC connector for 0 to 15 V.

Mains isolation voltage: Input/Output (signal) 3000 Vac; Input/Chassis(ground) 1500Vac

Dimensions: 200(W) x 76(H) x 280(D) mm

Weight: 1.5 kg

Power Supply Section compliant with

Radiated emissions EN55022/11, FCC part 15 Level A .

Conducted emissions EN55022/11,FCC part 15 Level B

Electrostatic discharge EN61000-4-2 Level 2

Electrical fast transients/bursts EN61000-4-4 Level 3

Surge Susceptibility EN61000-4-5 Level 3

RF field susceptibility EN61000-4-5 Level3

RF conducted disturbance EN61000-4-6 Level 3


The Synchroniser is constructed using RoHS compliant materials

Ordering Information


 Must specify what chopper is used in conjunction with the synchroniser

Useful Documents


Synchroniser Datasheet - pdf (68K)

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