Controller Setting
When the SCU5 controller is used for web guiding purposes the controller settings such as gain, deadband,
etc.can be set from this screen.
Gain
The gain setting needs to be changed based on the
actuator lead screw and the mechanical advantage of
the web guide structure. The gain value sets the
maximum distance the actuator would move based on
the error magnitude. Unlike conventional controllers, the
Roll-2-Roll SCU5 web guide controller is a complex
non-linear position based controller which has
independent settings for position gain, velocity and
acceleration of the actuator. The maximum stable gain
setting for the actuator or web guiding system depends
on the pitch of the lead screw, the microsteps of the
driver, the mechanical advantage of the web guide
structure. Typically the controller is preset with the recommended gain values from the factory.
NOTE:
If the gain is set to zero then the actuator will not respond to any error when in automatic mode.
NOTE:
The gain setting is independent of the speed and acceleration setting.
WARNING:
This parameter may affect the stability of the overall web guiding system and hence should be
changed with care.
Deadband
Deadband is the region around the guidepoint where the actuator will not be actuated if the web is within
this deadband. This integer value is in pixels and by default the deadband value is 4 pixels or 0.25 mm. With
that setting, the actuator will not move if the web is within ± 4 pixels or ±0.25 mm from the guidepoint.
Setting a deadband of zero will make the actuator move as long as the error is non-zero.
NOTE:
Wider deadbands can be used for webs with ragged or irregular edges.
NOTE:
Setting the deadband to zero will make the actuator move all the time. It is not advisable to set the
deadband to zero.
Reverse Error Polarity
The error polarity for the web guiding system can be reversed by turning ON the reverse polarity button.
This might be needed based on the web guide installation as well as the sensor installation.
NOTE:
If the polarity is set wrong, then the web guide will go to an extreme position as soon as the
controller is in Automatic web guiding mode.
Content subject to change without notice
SCU5: Sensor and Web Guide Controller User Manual v 3.6| Page 40
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