Block Search; Gi Monitors - Siemens SINUMERIK 840C Installation Instructions Manual

12.93
12.18.10

Block search

Block search is only meaningful if executed with calculation. The GI commands are in this
case executed as in normal program mode, i.e. the GI status is established as if the system
were operating in normal program mode.
Exception: On-the-fly synchronization is not executed (no traversal of following drive).
A block change is implemented immediately in response to GI commands even when the
signal INTERLOCK LINK ON/OFF is present.
In order to prevent traversal of following drives after LINK ON as a result of leading axis
movements from other channels, the signal INTERLOCK LINK ON should be applied from the
PLC while the block search is in progress. The link does not then become effective until the
target block is reached.
If a block search is carried out when the link is active, the following drive positions in the target
block remain undefined since no axis movements take place. If reference is made to defined
positions of the following drive on completion of the block search, then a G403 (on-the-fly
synchronization) must be executed after the target block.
In the case of other block search modes, problems may occur if it is necessary to enter into
an active link. In such cases, the skipped GI commands must be activated prior to NC start
(for example, via input display).
12.18.11

GI monitors

In the LINK ACTIVE state, GI-specific monitoring routines are activated for the following drive
in addition to the monitoring functions which are normally performed on NC axes/spindles.
These routines are described in detail below.
© Siemens AG 1992 All Rights Reserved
SINUMERIK 840C (IA)
6FC5197- AA50
12 Functional Descriptions
12.18.10 Block search
12–141