MPH-02, MPB-02, MPD-02
Motor, Mechanical Axis System, Measuring Systems
5-51
DOK-INDRV*-MP*-02VRS**-FK01-EN-P
Position measuring systems are available for the different kinds of motion
in adapted types of construction:
•
rotary
encoders
•
linear
encoders
With the appropriate signal specification, encoders in both types of
construction can be evaluated by IndraDrive controllers.
Depending on their design and the mechanical arrangement at the axis,
the position encoders can be evaluated as
•
relative encoders (incremental encoders)
- or -
•
absolute encoders (absolute value encoders).
In the case of relative position measurement, only position differences
can be evaluated by means of the measuring system. The actual position
values signaled by the measuring system refer to the (mostly undefined)
position at the time the drive is switched on. To operate the drive within a
limited travel range a position reference must be established ("homing")
after each time the drive is switched on again.
In the case of absolute position measurement, the encoder signals actual
position values with a fixed encoder-dependent reference point to the
controller. After each time the drive is switched on the correct actual
position value is immediately available with each axis position. Due to the
mostly undefined mounting situation of the encoder to motor or
mechanical axis system, it is necessary to determine the position offset
("setting the absolute value") once at the initial commissioning.
The precision of the position measurement depends on:
•
the resolution of the measuring system (division periods = DP)
•
the absolute encoder precision
•
the digitalization quality of the analog encoder signals
•
the dimension of the travel range of the axis
Correct position information is of fundamental importance for reliable
drive behavior and motion according to contour. The encoder signals are
therefore monitored for plausibility and compliance with the allowed
tolerances.
In addition, it is possible to monitor drives with an encoder that can be
evaluated in absolute form for compliance with the position when
switching on compared to the last time the drive was switched off.
It is also possible to monitor the difference between the actual position
values of motor encoder and external encoder.
See section "Monitoring the Measuring Systems"
For connecting the measuring systems to the controller there are
3 optional interfaces available. The parameters
P-0-0077, Assignment
motor encoder->optional slot
and
P-0-0078, Assignment optional
encoder ->optional slot
define the interface to which the respective
encoder is connected. It must be equipped with the encoder input
appropriate for the encoder.
See also separate documentation "Project Planning Manual for
Control Sections
Types of Position Measuring
Systems
Evaluating Position
Measurement
Relative Position Measurement
Absolute Position Measurement
Precision, Resolution
Monitoring Functions
Hardware Requirements
Courtesy
of
CMA/Flodyne/Hydradyne
▪
Motion
Control
▪
Hydraulic
▪
Pneumatic
▪
Electrical
▪
Mechanical
▪
(800)
426-5480
▪
www.cmafh.com
