HEIDENHAIN PROFIBUS-DP (DPV2) - Manual (Page 90)

Encoder state machine
90
9.1 Normal operation state
9.1.1 Profile version 4.x
If using encoder complying with encoder profile v4.1, then bit 10
Control by PLC in Control word 2 needs to be set before the data
in Control word is valid. If not set, Control word is not used by the
encoder firmware.
9.1.2 Profile version 3.x
If using encoders complying with encoder profile 3.x, the data in
Control word is always valid and bit 9 Control requested in Status
word 2 is always cleared.
9.1.3 Profile version 3.x and 4.x
When using telegram 81-83 and Control word bit 13 Request
absolute value cyclically is set, then Status word bit 13 Transmit
absolute value cyclically is set. Status word bit 13 is cleared (bit
13=0) when Control word bit 13 is cleared. Status word bit 13 is
always cleared, when using telegram 84 due to the fact that no
absolute value is sent in G1_XIST2.
9.2 Parking state
This state can be reached from any other state. The position value
in G1_XIST1, G1_XIST2 and G1_XIST3 are set to zero. Errors are
cleared and alarms are disabled in parking mode.
9.3 Set/shift home position (Preset)
The Set/shift home position is initiated when Control word bit 12
Request set/shift of home position is set. In this case the Status
word bit 12 Set/shift of home position executed is set to 1. In
order to initiate a set/shift home position, Class 4 functionality
must be enabled (see chapter 8.2), otherwise there will be an
error in G1_XIST2.
9.3.1 Preset depending on different telegrams
When using standard telegram 81-83, the acyclic encoder
parameter 65000 Preset value 32 bit shall be used to set a preset
value (<=32 bit) for the encoder. If the acyclic encoder parameter
65002 Preset value 64 bit is used in this case, an error message
on the acyclical parameter channel will be returned. With telegram
81-83, the operating status must be read by encoder parameter
65001 Operating status 32 bit.