IC-ML Datasheet, PDF (14/17 Pages) IC-Haus GmbH – HALL Position Sensor / Encoder

iC-ML
HALL Position Sensor / Encoder
Incremental ABZ modes
Rev A3, Page 14/17
Mode NEN CFG1 CFG2 CFG3
Incr. ABZ
ABZ 8-1 low low low open
ABZ 8-0 low open low open
ABZ 7-1 low low open open
ABZ 7-0 low open open open
ABZ 6-1 low low high open
ABZ 6-0 low open high open
ABZ 8-1 low low low high
ABZ 8-0 low open low high
ABZ 7-1 low low open high
ABZ 7-0 low open open high
ABZ 6-1 low low high high
ABZ 6-0 low open high high
Port A
A
A
A
A
A
A
A
A
A
A
A
A
Port B
B
B
B
B
B
B
B
B
B
B
B
B
Port C
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Port D Res. Comments
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
8 AB=1
8 AB=0
7 AB=1
7 AB=0
6 AB=1
6 AB=0
8 AB=1, PRM
8 AB=0, PRM
7 AB=1, PRM
7 AB=0, PRM
6 AB=1, PRM
6 AB=0, PRM
iC-ML has an 8-bit sine/digital converter which can
convert the sine/cosine sensor signals into a digitized
angle. This angle is made available at the ports as an
incremental value. Signal Z is always high when the
angle is 0°; otherwise the signal is low. In all incremen-
tal modes of operation error signal NERR is available
so that the plausibility of the counter value can be veri-
fied. At an amplitude which is less than 50 % of the set
amplitude the error signal switches to low; at an ampli-
tude greater than 70 % the error signal is reset, i.e. set
to high.
Three different quantities regarding the number of
edges per rotation of the magnet can be selected.
These are a resolution of 6 bits (64 edges per rota-
tion), 7 bits (128 edges) or 8 bits (256 edges). The
conversion process is count-safe, i. e. the output of all
edges up to the current angle position is guaranteed as
long as the input frequency is less than the maximum
possible rotation.
sensor via NEN at low the sensor looks for its oper-
ating point. If 70 % of the set amplitude is achieved the
error signal is reset. An error status during this phase
is also signaled when signals A and B are high and Z
low. In an error-free state Z is always high at zero po-
sition. iC-ML continues to search for its operating point
by outputting the position of the external magnetic field
at maximum count frequency via the incremental in-
terface. Once the actual position has been obtained
the device follows a changed input signal in real time.
The edge frequency is thus 256 times the frequency of
periodical movement of the magnetic tape at a set res-
olution of 8 bits. If a (rising) edge reaches B before a
(rising) edge A, this means that the counter value has
risen. If the edge reaches A before B, however, this
indicates that the absolute value is lower.
All incremental resolutions also have a reduced power
consumption mode(PRM). In this mode the Hall sen-
sor is supplied with current intermittently, reducing the
power consumption. Here it must be noted that the
maximum input frequency drops by a factor of 2.
A distinction can be made between the various modes
of operation by studying the level of the AB signals on
the Z pulse. In mode AB = 1 signals A and B are both
high, as is Z at an angle of 0°. In mode AB = 0, how-
ever, both signals A and B are low when the Z signal
is high.
Firstly, the behavior of the sensor on switching on the
device is described when the magnetic tape moves in
the +x-direction (Figure 17). After switching on the
NEN
NERR
A
B
Z
Time [us]
Figure 17: Incremental signals after switching on
the device, counting up