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Product description
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Festo – GDCP-CMMO-ST-EA-SY-EN – 2017-05c – English
2.5.9
Force mode
Force mode makes it possible to apply constant power, with the option of stroke limitation. The func
tion requires close-loop control operation (motor with encoder). Stroke is defined as the absolute
difference between the actual position and the position at the start of the order. Stroke limitation de
termines the maximum permitted stroke, relative to the starting position.
Variants
Description
Without stroke limitation
Travel over an unlimited distance
With stroke limitation
Covers a limited distance relative to the start position
Tab. 2.46 Order variants in power mode
Force is controlled by closed-loop control of motor current. Depending on the mechanism of the actu
ator, a torque level or a linear force can be determined from the level of current measured. The target
specification is based on a percentage basis on the nominal motor current. The actual force at the axis
must be checked during commissioning using external measurement devices, and parameterisation
should be adapted as required.
Parameters
Description
Force (Force)
Target specification for force (% related to nominal motor current)
Speed (Velocity)
Setpoint value for speed (velocity)
Tab. 2.47 Parameters in force mode
Target recognition
The characteristics when the target position are reached (target recognition) depends on the stroke
limitation.
Target recognition
Behaviour after target recognition:
… without stroke limitation
Force is reached i.e. the actual
motor current is located in the
time window the defined
damping time.
The “Motion Complete” signal is set. As long as no other actuator
function is executed, the actuator will continue to be controlled by
the setpoint force.
The speed is limited to the maximum value specified in the order.
… With stroke limitation
–
Stroke limitation is reached
The “Stroke limitation” signal is set.
The actuator is braked down to a stop using the parameterised
Quick-Stop deceleration function. The actuator remains
position-controlled at the stroke limit. Stationary monitoring is
enabled and the “Motion Complete” signal is set.
–
Force is reached i.e. the ac
tual motor current is located
in the time window the
defined damping time.
The “Motion Complete” signal is set. As long as no other actuator
function is executed, the actuator will continue to be controlled by
the target force.
The speed remains limited to the maximum value specified in the
order. Stroke limitation remains active.
Tab. 2.48 Target recognition in force mode
