BEI Sensors MHK5 Absolute Hollow Shaft Encoder - Manual (Page 23)

5.2 Data exchange in normal operation
With the manufacturer-specific versions 2.1 and
2.2 the process value generally is transmitted as
32-bit-value (peripheral double word). Apart from
25 bits used for the position value the 7 other bits
are used as status bits. The output double word
contains the preset value and control bits.
Absolute encoders model series “MHM5” might
have (physical) position values > 25 Bit. The
manufacturer specific versions do not support the position values > 25 Bit. The upper digits will be
overwritten by the status bits. If the versions are
used with encoders with a total (physical)
resolution > 25 Bit, the user has to assure that the
position value is scaled to a maximum output value
< 33554432. If position values > 25 Bit are
necessary class 2 should be used.
If version 2.2 is used the current velocity is
transmitted in an additional (peripheral) input word.
ID F1 hex D0 hex
Status + position value Velocity MHM5 → Master
Status + 2 24 2 23 - 2 16 2 15 - 2 8 2 7 - 2 0 2 15 - 2 8 2 7 - 2 0
Preset value + control bits Master → MHM5
Control + 2 24 2 23 - 2 16 2 15 - 2 8 2 7 - 2 0
Meaning of the different status bits:
Bit 28 Bit 27 Bit 26 Bit 25 Meaning
Ready
0 = encoder is not ready for operation
1 = encoder is ready for operation
Mode
0 = commissioning mode
1 = normal mode
Software limit switch
0 = lower limit switch ≤ current position value ≤ upper limit switch
1 = current position value > upper limit switch or
current position value < lower limit switch
Code sequence
0 = increasing clockwise (view onto the shaft)
1 = increasing counter clockwise (view onto the shaft)
Revision 03/10 BEI Sensors Profibus Manual serie M Page 23