External Device Connection 1 -Differential Line Receiver Input; Connecting The Differential Line Receiver Input; Detailed Description Of Differential Line Receiver Input Circuit - Contec CNT-3208M-PE User Manual

External Device Connection 1
-differential line receiver input-

Connecting the differential line receiver input

Use the differential line receiver input to connect the board to the line receiver output circuit of a rotary
encoder or linear scale. The maximum input frequency is 10 MHz.
For use in two-phase input mode, connect both of the phase-A and phase-B inputs. For use in single-
phase input mode, connect either of them. If phase-Z is not used, the input need not be connected.
For differential line receiver input mode, you can select whether to insert the terminal resistor.

Detailed description of differential line receiver input circuit

Board
+5V
1kΩ
Internal
circuit
Equivalent to 26LS32
1kΩ
Figure 3.3. Differential line receiver input circuit and its sample connection
To protect the input circuit from voltage surges, a varistor is connected.
t t
PWL PWH
t
PWH : High-level count input pulse width 50nsec (Min.)
t
PWL : Low-level count input pulse width 50nsec (Min.)
Figure 3.4. Input signal
CAUTION
- In the input pin+, TTL level input circuit is parallel-connected.
- Please use the shielded cable with a length of less than 30m to meet "CE EMC Directive".
CNT-3208M-PE
ALS541
51Ω
Varistor
150Ω
51Ω
Varistor
External power supply
5VDC
Target equipment
Pulus
common
Input Output
pin+ pin+
Output
Input
pin-
pin-
Minus
Ground
common
3. External Connection
Equivalent
to 26LS31
31