AVL F-FEM-CON User Manual

Operation
58
F-FEM-CON — User’s Guide
4.6.6.1 Single Edge Evaluation
With a single edge evaluation the counting pulse is generated at the rising edge
only.
With a two-track signal the direction of rotation is detected as a function of the
level of the second track.
Pro: Unbalances of the encoder (if the length of the high-pulse is not equal to the
length of the low-pulse) have no impact (see red arrow).
Con: reduced resolution at lower speeds.
4.6.6.2 Multi Edge Evaluation
A multi edge evaluation generates a counting pulse at the rising edge and at the
falling edge.
With a two-track encoder every edge of one track counts, in dependence of the
level of the other track, either up (right) or down (left).
Pro: maximum possible resolution at low frequencies (speeds); interfering
signals can be detected and suppressed.
Con: all unbalances of the sensor (pulse width of individual tracks unequal 50%
and different from each other; tracks are not in quadrature, i.e. phase displace-
ment unequal 90°) impact the measurement signal in form of speed fluctuations
and jitter (see red arrows). To minimize these impacts use the incremental
(RS422) input, whenever possible. Try to avoid the digital input, because it can
increase the jitter due to different high-low edge transistions.
Track A, Z
Counting pulses 1 1
Track A
Counting pulses 1 1
Track B
Track A
Counting pulses
1
2
1
2
Track A
Counting pulses
1
2 3 4
1
2 3
Track B

AVL F-FEM-CON Specifications

General

Brand	AVL
Model	F-FEM-CON
Category	Measuring Instruments
Language	English