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Product description
Festo – GDCP-CMMO-ST-EA-SY-EN – 2017-05c – English
61
“Following error” message
With positioning and velocity modes, any exceeding of the max. permitted following error can be mon
itored, e.g. in the event of impaired ease of movement or overloading of the actuator.
From the parameters of an order, before it is executed, a theoretical set of characteristics is calculated
(
è
). While carrying out an order, the variance between the calculated setpoint and the
current actual value is monitored. The permitted difference (max. permitted following error) is defined
by means of parameterisation. The message is enabled if the difference between the setpoint and
actual value of the current variable (displacement, velocity), the time parameterised here lies outside
the permitted difference.
Target position
t1
Damping time
Start
Following error
Message 2F
h
(Warning)
1
2
3
s
t1: Damping time for following error
1
Nominal positioning characteristics
2
Max. Following Error
3
Actual positioning characteristics
Fig. 2.13 Timing diagram: message “Following error” - example, positioning control, warning
The error management functionality of FCT makes it possible to parameterise the response to this
message (2F
h
) (
è
FCT error management). If the following error was configured as a warning, the
message is deleted automatically once the actual value once again lies inside the following error win
dow.