Variable Monitors - Siemens SINUMERIK 840Di sl Function Manual

12/2008
Fig. 2-26: 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,
counters, 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.
Individual 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
variables in the control is compensated for by the system because the count is
resumed 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.
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ePS Network Services, Function Manual (FH) - Release 12/2008
2.2 Variable monitors - Measurements and measurement series
2 Maschine information
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