Siemens SINUMERIK 804D sl Commissioning Manual page 109

Figure 10-1
Key to Fig. above:
T
Lag
T
DP
T
DX
T :Master time: Offset of the start time for NCK position controller
M
GC: Global Control: Broadcast message for cyclic convergence of the equidistance between
DP master and DP slaves
R: CPU time
Dx: Useful data exchange between the DP master and DP slaves
MSG: Acyclic services (e.g. DP/V1, pass token)
RES: Reserve: "Active pause" until the isochronous (equidistant) cycle has expired
Error response
• Alarm: "380005 PROFIBUS DP: Bus access conflict, type t, counter z"
Cause of errors/error handling
• t = 1
• t = 2
CNC Part 1 (NCK, PLC, drive)
Commissioning Manual, 11/2006, 6FC5397-2AP10-2BA0
Position control cycle offset compared to PROFIBUS DP cycle
:CPU time required by position controller
:DP cycle time: DP cycle time
:Data Exchange Time: Total transfer time for all DP slaves
The position-control cycle offset selected is too small. The cyclic PROFIBUS
communication with the drives was not yet completed with the start of the position
controller.
– Remedy: Increase the position-control cycle offset.
NCK start-up
10.2 System data
109