Siemens SINUMERIK 840C Installation Instructions Manual page 1077

12 Functional Descriptions
12.29.2 General hardware conditions for "Extended measurement"
SIMODRIVE 611D:
• 611D measuring circuits can evaluate both measuring probes alternatively; they can also
react to the following signal edge sequences: "rising/rising", "falling/falling" or "alternately
rising/falling".
In this case, the minimum permissible time interval between two measured values
corresponds to one position controller cycle, i.e. if values are measured at short intervals,
measured data will be lost. Within this position control cycle, one rising edge and one
falling edge of each probe can be evaluated.
• Response to probe "bouncing":
In the case of multiple edges (probe "bouncing") within one position controller cycle, the
measured value belonging to the first edge is always read out.
Mixed operation:
If various measuring circuit variants are used, then the following applies to the available
measuring functionality:
Measuring circuit variants used
SPC/HMS PCA
– PCA
SPC/HMS –
SPC/HMS PCA
Measuring circuit switchover:
Any attempt to switch over the active measuring system (switchover of first/second measuring
system by PLC signal DB 32, DL k + 2, bit ) while measurement is in progress likewise leads
to abortion of the G720/G721 block with output of a RESET alarm.
Reactions to disturbances/errors relating to "Extended measurement"
Through evaluation of the actual number of measured values in the start address for the R
parameter field of each axis involved, a part program cycle can detect in the case of abortion
or at a block end whether the measurement (actual number = programmed number) was
complete in each axis.
The decoding function detects the following G720/G721 programming errors:
• Specification of non-existent R parameter ranges
• Specification of overlapping R parameter ranges (in the same block)
• Specification of non-existent axes
• Programmed number of measured value = number of measurements to be taken *
number of axes in a G720/G721 block does not fit into the available R parameter range
• Incomplete data
Alarm 3006 "Incorrect block structure" is output in response to one of the above errors.
12–302
SIMODRIVE 611D
SIMODRIVE 611D
SIMODRIVE 611D
–
© Siemens AG 1992 All Rights Reserved
10.94
Measuring functionality
as for
SPC/HMS
PCA
SPC/HMS
SPC/HMS
6FC5197- AA50
SINUMERIK 840C (IA)