Page 51
Operation
optoNCDT 1700
6.13 Timing, Measurement Value Flux
The controller operates internally with real time cycles in a pipeline mode:
1. Exposure: Charging the image detector in the receiver (measurement).
2. Reading: Reading out of the imaging device and converting into digital data.
3. Computation: Measurement computation.
4. Controlling
The output through the analog and digital interface starts with the beginning of every new cycle. The analog
value and digital switch outputs are updated immediately and the digital output starts with the start bit.
Each cycle takes 400 μs at a measuring rate of 2.5 kHz (speed=1). The measured value N is available after
each cycle with a constant lag of four cycles in respect to the real time event. The delay between the input
reaction and the signal output is therefore 1.2 up to 1.6 ms. The processing of the cycles occurs sequentially
in time and parallel in space, see Fig. 32, pipelining). This guarantees a true constant real time data stream.
Cycle 1. 2. 3. 4. 5.
Time 400 µs 800 µs 1200 µs 1600 µs 2000 µs
1. Layer Exposure N
(Output N-4)
Reading N Computation N Controlling N Exposure N+4
(Output N)
2. Layer Controlling N-3 Exposure N+1
(Output N-3)
Reading N+1 Computation N+1 Controlling N+1
3. Layer Computation N-2 Controlling N-2 Exposure N+2
(Output N-2)
Reading N+2 Computation
N+2
4. Layer Reading N-1 Computation N-1 Controlling N-1 Exposure N+3
(Output N-1)
Reading N+3
Fig. 32 Sensor timing
To Next Page
Loading...