2 Machine information
08/2008
2.2 Measurements and measurement series
© Siemens AG 2008 All Rights Reserved
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ePS Network Services, Function Manual (FH) - Release 08/2008
Fig. 2-28: Time series for a universal axis test
2.2.7 Variable monitors
Description of functions
Variable monitors enable the recording in the control of changes over time of any
status data. The variable monitors are essentially for long-term recording in slow
data recording cycles (as opposed to the PLC trace).
Up to 32 variables can be recorded in a common cycle in a variable monitor. The
PLC variables recorded can be from the PLC environment: inputs, outputs, count-
ers, flags, and any data addresses in PLC blocks. From the NC environment, they
can be machine data, setting data, system variables and others.
The variables recorded can be scaled and assigned freely definable units. Individ-
ual variables of a variable monitor can be identified as counting variables (e.g.
workpiece counters). These variables can be used in the configuration of interval
triggers to trigger recurring actions after a certain number of counting units have
elapsed. Counting variables are counted up monotonically. Resetting of the vari-
ables in the control is compensated for by the system because the count is re-
sumed on the basis of the last value before reset.
Limit values can be configured for each variable for automatic monitoring of the
state. Actions can be triggered when limit values are violated. This is the same as
described for the control monitors.