BEI Sensors MHK5 Absolute Hollow Shaft Encoder - Manual (Page 15)

For multiturn devices with 16384 revolution the rule
is as follows (if it is necessary to turn the encoder shaft more than 4096 revolutions without power
supply):
The period, i.e. “Total resolution” / “measuring units” per revolution must be an integer and it must fit an
integer number of times (integer multiple) into 16384. So the following equation must apply:
(16384 x measuring units per revolution) / Total resolution = integer
4.2 Data exchange in normal operation
The „DDLM_Data_Exchange mode“ is the normal
operation mode of the device. On request the
encoder transfers the current (position) value to the master. The encoder can also receive data from
the master (e.g. the preset value in the class 2
configuration).
4.2.1 Transferring the process value
The multiturn encoder transmits the current
position value as a 32-bit-value (double word) to
the master.
Word
Word 1 Word 0
Function Process value
Bit
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0 X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X
The Singleturn encoder uses a 16-bit-value (word)
for data transmission.
4.2.2 Preset function
Using the preset function it is possible to adapt he
encoder zero point to the zero point of the
application. When using this function the current
encoder position value is set to the desired preset
value. The integrated microcontroller calculates the
internal zero point shift. It is stored non-volatile in
an EEPROM (takes less than 40 ms).
The preset value is activated if bit 31 in the
(peripheral) output double word is set to 1 (rising
edge). As the preset function is used after receiving the scaling parameters the preset value
refers to the scaled position value.
Revision 03/10 BEI Sensors Profibus Manual serie M Page 15