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300CD Optical ChopperFeatures

 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 additionally the time difference (lead/lag) that can be controlled by the USB interface of the Synchroniser.

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 to the optical chopper reference, the synchroniser control to the optical chopper control and the synchroniser master to your signal for which you wish the optical chopper to synchronise to.

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 the chopper or the synchroniser powered with the other unit off.

Also avoid unit off with reference applied.

The recommended start up sequence for operation is;
Set the optical Chopper to EXT. If the Optical Chopper is a 300CD unit then the manual speed control should be set fully clockwise. This is not necessary for 310CD unit.

With the Master Reference disconnected or switched to 0V power up both the synchroniser and the optical chopper. Wait for 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 to disconect or disable 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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