Manual PD4-C (USB)
10 Special functions
Version: 1.4.1 / 22.07.2016 / FIR-v1626
73
The function is only available when the motor controller is in closed loop operating mode (bit 0 of object
3202
set to "1") and the motor is not in profile torque mode or cycle synchronous torque mode.
There is a single exception: If I
2
t is activated in open loop mode, the current is limited to the set
nominal current even when the set maximum current is greater. This feature was implemented for
safety reasons, so that it is also possible to switch out of closed loop mode and into open loop mode
with a very high short-time maximum current without damaging the motor.
10.2.2 Object entries
The following objects affect I
2
t motor overload protection:
•
h
: Peak Current - specifies the maximum current in mA.
•
:1
h
Nominal Current - specifies the nominal current in mA.
•
:2
h
Maximum Duration Of Peak Current - specifies the maximum time period of the maximum
current in ms.
The following objects indicate the actual state of I
2
t:
•
:3
h
Threshold - specifies the limit in mA, from which is determined whether switching is to the
maximum current or nominal current.
•
:4
h
CalcValue - specifies the calculated value that is compared to the threshold in order to set
the current.
•
:5
h
LimitedCurrent - shows the actual current value that was set by I
2
t.
•
:6
h
Status:
•
Value = "0": I
2
t deactivated
•
Value = "1": I
2
t activated
10.2.3 Activation
The three object entries above must have been appropriately specified to activate the mode. This
means that the maximum current must be greater than the nominal current, and a time value must be
entered for the maximum time of the maximum current. I
2
t operability remains deactivated when these
conditions are not satisfied.
10.2.4 Function of I
2
t
A I
2
T
Lim
is calculated by specifying the nominal current, maximum current, and maximum time period
for the maximum current.
The motor can run with maximum current until the calculated I
2
T
Lim
is reached. The current is then
immediately reduced to the nominal current.
The following diagram again shows the interactions.
