Siemens SIMATIC FM 452 Manual page 124

Settings
9.12 Position and Track Data
Definition
With the setting "position and track data", you read the current actual position, the
feedrate and the track flag bits. The track flag bits are acquired before they are
logically combined with machine and channel data.
The calculation algorithm implemented on the FM 452 calculates speed changes
higher than 1 pulse per 4 ms with a slight inaccuracy The displayed speed is
therefore not fully accurate and is not suitable for control purposes. The internal
speed used for the cam dynamics is more accurate.
Sequence of the Setting
1. Set the trigger bit in the channel DB.
2. The data are stored in the channel DB.
Data Used in the Channel DB
Address Name
38.4 ACTPOS_EN
128.0 ACTPOS
132.0 ACTSPD
136.0 TRACK_ID
9-26
Type Initial Value
BOOL FALSE
DINT L#0
DINT L#0
DWORD DW#16#0
Comment
1 = read position and track data
Current position
Current feedrate
Track flag bits of tracks 0 to 31
FM 452 Electronic Cam Controller
C79000-G7076-C452-04