Additional Analog, Incremental Real-Time Signal (Bml-S1G0; Additional Digital, Incremental Real-Time Signal (Bml-S1G0 - Balluff BML-S1G0-B7-M5E-0-S284 Serie Betriebsanleitung

BML-S1G0-B/S7_ _-M5E_-_0-(SA26-)S284
Absolute Magnetically Coded Position Measuring System
6
Interfaces (continued)
6.3 Additional analog, incremental real-time
signal (BML-S1G0-_ _ _ _-M5EA-_0-...)
With the analog sine and cosine signals +A (+sin),
−A (−sin), +B (+cos) and −B (−cos), the controller evaluates
the difference in signal amplitudes and, from the signals,
interpolates the precise position within a period (Fig. 6-5).
For a movement over several periods, the controller also
counts the number of periods.
For correct function, the sine signal +A (+sin) −
(−A (−sin)) and the cosine signal +B (+cos) − (−B
(−cos)) must be evaluated depending on the
direction.
Output voltage
+A (+sin) − (−A (−sin))
+B (+cos) − (−B (−cos))
Signal periods 360° el.
0° 90°
Fig. 6-5: Signals of the sine and cosine sensor (2 mm pole width) for
forward movement
The sensor transmits the measurement as an analog sine/
cosine differential signal with an amplitude of approx. 1 Vss
(peak/peak value) within the assembly tolerances to the
controller. The period is 2 mm.
If the sensor is supplied with voltage that is
isolated from the processing electronics, the
GND for this voltage must be connected to the
GND of the processing electronics.
+A (+Sin)
−A (−Sin)
Fig. 6-6: Circuitry example of subsequent electronics with analog
output
+A (+sin) − (−A (−sin)) (+B (+cos) − (−B (−cos))
correspondingly)
www.balluff.com
Distance [µm]
180° 270° 360°
6.4 Additional digital, incremental real-time signal
(BML-S1G0-_ _ _ _-M5EQ-_0-...)
The sensor transmits the measurement to the controller as
a digital differential voltage signal (RS422).
Edge distance A/B corresponds to the resolution of the
sensor head (note minimum edge distance, see
page 22).
Signal periods 360° el.
+A
+B
Fig. 6-7: Digital output signals for forward movement
+5V
+A
Z1 120 Ω A
–A
GND
Fig. 6-8:
Circuitry of subsequent electronics for digital output
If the sensor is supplied with voltage that is
isolated from the processing electronics, the
GND for this voltage must be connected to the
GND of the processing electronics.
The two digital differential signals 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 (Fig. 4-1).
Each edge change of A or B is a counting step for the
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).
For correct function, the A and B signal must be
evaluated depending on the direction.
Signal A
Signal B
Increment
Forwards
Direction of movement
Counter reading (ex.)
Fig. 6-9: Digitized sine and cosine signal with counter
A channel
Backwards
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