iC-MA
ANGULAR HALL SENSOR / ENCODER
Rev B3, Page 15/18
Incremental ABZ modes
Mode
NEN CFG1 CFG2 CFG3
Port A
Port B
Port C
Port D Res. Comments
Incr. ABZ
ABZ 8-1 low
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
low
low open
A
A
A
A
A
A
A
A
A
A
A
A
B
B
B
B
B
B
B
B
B
B
B
B
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
NERR
8
8
7
7
6
6
8
8
7
7
6
6
AB=1
AB=0
AB=1
AB=0
AB=1
AB=0
AB=1, PRM
AB=0, PRM
AB=1, PRM
AB=0, PRM
AB=1, PRM
AB=0, PRM
iC-MA has an 8-bit sine/digital converter which can 14). After switching on the sensor via NEN at low the
convert the sine/cosine sensor signals into a digitized sensor looks for its operating point. If 70 % of the set
angle. This angle is made available at the ports as an amplitude is achieved the error signal is reset. An error
incremental value. Signal Z is always high when the status during this phase is also signaled when signals
angle is 0°; otherwise the signal is low. In all incremen- A and B are high and Z low. In an error-free state Z
tal modes of operation error signal NERR is available is always high when the angle is 0°. iC-MA continues
so that the plausibility of the counter value can be veri- to search for its operating point by outputting the angle
fied. At an amplitude which is less than 50 % of the set of the external magnetic field at maximum count fre-
amplitude the error signal switches to low; at an ampli- quency via the incremental interface. Once the angle
tude greater than 70 % the error signal is reset, i.e. set has been obtained the device follows a changed input
to high.
signal in real time. The edge frequency is thus 256
times the frequency of rotation of the magnet at a set
Three different quantities regarding the number of resolution of 8 bits. If a (rising) edge reaches B before
edges per rotation of the magnet can be selected. a (rising) edge A, this means that the counter value
These are a resolution of 6 bits (64 edges per rota- has risen. If the edge reaches A before B, however,
tion), 7 bits (128 edges) or 8 bits (256 edges). The this indicates that the absolute value is lower.
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.
NEN
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
NERR
power consumption. Here it must be noted that the
maximum input frequency drops by a factor of 2.
A
A distinction can be made between the various modes
of operation by studying the level of the AB signals on
B
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-
Z
ever, both signals A and B are low when the Z signal
is high.
Time [us]
Firstly, the behavior of the sensor on switching on the
device is described when the permanent magnet ro-
tates in the direction of the increasing angle ω (Figure
Figure 14: Incremental signals after switching on
the device, counting up
ICHAUS [ IC-HAUS GMBH ]
