IC-MN_16 Datasheet, PDF (47/62 Pages) IC-Haus GmbH – 25-BIT NONIUS ENCODER WITH 3-CH. SAMPLING 13-BIT Sin/D INTERPOLATION

iC-MN 25-BIT NONIUS ENCODER
WITH 3-CH. SAMPLING 13-BIT Sin/D INTERPOLATION
Rev F2, Page 47/62
MT INTERFACE
In nonius modes iC-MN can connect to an external
multiturn sensor via the serial MT interface. Following
synchronization of the MT data with the ST data the
multiturn period counter is set to its initial position. Each
further revolution is then logged by the internal period
counter.
ST MSB -1
ST MSB
MT LSB -2
180° 270° ^{0° 90°} 180° 270° ^{0° 90°}
Even when the MT interface is not employed, the inter-
nal 24-bit multiturn period counter can be configured
to complement singleturn position data output by a
counted multiturn position (see M2S).
Additionally, the MT interface can be configured as a
parallel two-pin interface to read in a single bit multiturn
position accompanied by a synchronization bit. In this
way coverage of the absolute singleturn position can
be doubled if additional sensors provide 180 and 90
degree sector information.
MODE_MT
Code
00*
10*
11*
Notes
Addr. 0x40; bit 4:3
Function
Multiturn position counted internally
Serial MT interface active (SSI)
Parallel MT interface active (2-bit mode):
Pin MTMA is input for 180° and pin MTSLI input for
90° sector information
*) NCRC_MT = 0 required
If MODE_MT is altered during operation, command
SOFT_RES must be issued (see page 42).
Table 83: MT Interface operation mode
MT LSB -1
MT LSB
multiturn
data output
°/ST
Figure 19: Principle of 2 bit MT synchronization
Figure 20 shows the principle of a 1 bit MT synchroniza-
tion for ideal signals (without indication of synchroniza-
tion tolerance limits) for leading and trailing signals.
ST MSB -1
ST MSB
MT LSB -1
180° 270° ^{0° 90°} 180° 270° ^{0° 90°}
Configuration Of Data Lengths
The bit length of the internal MT counter and of the
multiturn data word is set using parameter DL_MT. For
synchronization purposes the synchronization bit length
must be set by SBL_MT. Synchronization occurs be-
tween the external multiturn data read in and the period
information counted internally. At synchronization bit
lengths > 1 bit synchronization can occur automatically
within the relevant phase tolerances.
MT LSB
multiturn
data output
MT LSB -1
MT LSB
multiturn
data output
-1
-1
+1
+1
°/ST
With a single synchronization bit (SBL_MT = 00) no au-
tomatic synchronization can take place. Here, iC-MN
cannot recognize whether the external multiturn sensor
provides leading or trailing position data (what may vary
depending on gear box assembly). This must be set
manually by parameter LNT_MT.
Figure 19 shows the principle of a 2 bit MT synchroniza-
tion for ideal signals (without indication of synchroniza-
tion tolerance limits).
Figure 20: Principle of 1 bit MT synchronization
With a synchronization bit length of two or more bits
iC-MN ignores parameter LNT_MT selecting for leading
or trailing MT data. Synchronization bit lengths of 3 bit
or 4 bit enlarge further the synchronization tolerance
between multiturn and singleturn (see Table 85).