HEIDENHAIN PROFIBUS-DP (DPV2) - Manual (Page 91)

Encoder state machine
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9.3.2 Absolute preset with negative value
Preset data sent with acyclic encoder parameter 65000 or 65002
are signed values. The relative preset mode uses signed preset
values, but with the absolute preset mode no preset will be made
if a negative preset value (set with encoder parameter 65000 or
65002) is used while trying to initiate an absolute preset.
9.4 Error state
This state is reached when an error has occurred. The encoder
can enter this state from both the normal operation state and the
set/shift home position state. If an error occurs, the Status word
bit 15 Sensor error is set, and the error code is displayed in
G1_XIST2 instead of the position value.
9.5 Error acknowledgement
This state is reached when an error has occurred, and Control
word bit 15 Acknowledging a sensor error has been set. The
Status word bit 11 Requirement of error acknowledgment
detected and Status word bit 15 Sensor error are set to 1.
9.6 Start up
This state is only reached when Control word bit 14 Activate
parking sensor are cleared (=0). Once the Control word bit 14 are
cleared, it takes about 500ms before the Status word bit 14
Parking sensor active are set to zero (=0). The reason for the delay
is that before the encoder goes to normal operation mode, an
initializing of the encoder is made.