MPH-02, MPB-02, MPD-02
Motor, Mechanical Axis System, Measuring Systems
5-59
DOK-INDRV*-MP*-02VRS**-FK01-EN-P
When the drive is switched off the current encoder data of the absolute
motor encoder and/or of the absolute external encoder are stored:
•
P-0-0177, Absolute encoder buffer 1 (motor encoder)
•
P-0-0178, Absolute encoder buffer 2 (optional encoder)
When switching on a drive with an absolute motor encoder and/or an
absolute external encoder, a check is run to determine in how far the
current actual position value differs from the actual position value at the
time of the last switch off. The maximum allowed difference is fixed in the
following parameters:
•
P-0-0095, Absolute encoder monitoring window for motor
encoder
•
P-0-0096, Absolute encoder monitoring window for opt. encoder
When the difference exceeds the determined value the respective error
message is output:
•
F2074 Actual pos. value 1 outside absolute encoder window
•
F2075 Actual pos. value 2 outside absolute encoder window
This monitoring function can be deactivated!
For axis drives that are equipped with an external encoder, the controller
provides the possibility of monitoring the difference of the actual position
values of motor encoder and external encoder with regard to a maximum
value that can be set. The monitor is only active when both encoders
were homed.
The maximum allowed difference of the actual position values of both
encoders is defined in parameter
S-0-0391, Monitoring window
feedback 2
. When this value is exceeded the
F2036 Excessive position
feedback difference
error message is generated. This monitoring
function can be deactivated!
The position data reference of absolute encoders gets lost when:
•
the parameter values of the mechanical drive system have been
changed
•
the encoder resolutions have been changed
•
the scalings of the physical data have been changed
•
the maximum travel range of an axis has been changed
•
hybrid position control has been activated ("measuring wheel mode")
During the transition from communication phase P2 to P4 (bb), the drive
recognizes that the former position data reference of the encoder does no
longer exist. It sets the parameter
S-0-0403, Position feedback value
status
of the encoder or encoders to "relative" and signals the loss of
position data reference by the following error messages:
•
F2174 Loss of motor encoder reference
•
F2175 Loss of optional encoder reference
In the case of spindles, it is mostly high-resolution, external encoders that
are used for C-axis operation, in order to obtain the required machining
quality for interpolating operation (with low speeds).
In the case of regular spindle operation (high speeds), it is possible that
the maximum input frequency of the respective encoder input is
exceeded. The drive then switches off with the
F2046 Max. signal
frequency of encoder 2 exceeded
error message.
The external encoder is only required for C-axis operation, but would
make regular spindle operation impossible. The encoder monitor can
Monitoring the Axis Position
when Switching On
Monitoring Mechanical Transfer
Elements
Monitoring the Position Data
Reference
Monitoring for Spindle Encoders
Courtesy
of
CMA/Flodyne/Hydradyne
▪
Motion
Control
▪
Hydraulic
▪
Pneumatic
▪
Electrical
▪
Mechanical
▪
(800)
426-5480
▪
www.cmafh.com
