Interfaces; Interface Signals; Digital Incremental Measuring System - Balluff BML-S series Betriebsanleitung

BML-S _ B/C/E0-Q _ _ _ -M4 _ _ - _ 0-KA _ _ /KA _ _-S284
Incremental Magnetic Linear Encoder
6

Interfaces

6.1

Interface signals

The sensor head converts the sine and cosine signals from
the incremental sensors in digital A/B impulses and
transfers them to the controller.
1.1.1

Digital incremental measuring system

The sensor transfers the measurement as a differential
voltage signal (RS422) or as an operational voltage (HTL)
to the controller (depending on the variant).
The edge distance A/B corresponds to the resolution of
the sensor head.
A
B
Z
Fig. 6-1: Digital output signals
The digital A/B impulses are interpolated in the sensor
head.
The two digital impulses A and B are electrically phase-
delayed by 90°, the algebraic sign of the phase difference
depends on the direction of movement of the sensor
(Figure 6-2).
Each edge change from A or B is a counting step for the
cycle counter (up/down counter). With a leading signal A,
the counter reading increases and it decreases with a
leading signal B. The controller knows the precise
increment position at all times, without having to
periodically query the sensor (real-time capability).
Notice:
For correct function, the A and B signal must be
evaluated depending on the direction.
Signal A
Signal B
Increment
Direction of
Forwards
movement
Counter
reading
Fig. 6-2: BML output signals with cycle counter
14 english
Sensor head
Fig. 6-3:
Fig. 6-4:
Backwards
PLC
E.g.
IC 26C32
E.g.
IC 26C32
E.g.
IC 26C32
Circuitry of subsequent electronics (RS422)
* for BML-S...-Q61..., ** for BML-S...-Q51...
TTL
(0/24 V)
A, B, Z
4k7
74C14
C 5.1 V
Circuitry of subsequent electronics (HTL)
BML-S...-Q53...
A channel
B channel
Z channel