ABB ACS880-x04, Firmware Manual

Page: 51 / 604

Program features 51
Position counter
The control program contains a position counter feature that can be used to indicate
the position of the load. The output of the counter function, parameter
90.07 Load
position scaled int , indicates the scaled number of revolutions read from the selected
source (see section Load and motor feedback on page 50 ).
The relation between revolutions of the motor shaft and the translatory movement of
the load (in any given unit of distance) is defined by parameters
90.63 Feed constant
numerator and 90.64 Feed constant denominator . This gear function can be changed
without the need of a parameter refresh or position counter reinitialization – however,
the counter output is only updated after new position input data is received.
For detailed parameter connections of the load feedback function, see the block
diagram on page
586 .
The position counter is initialized by setting a known physical position of the load into
the control program. The initial position (for example, the home/zero position, or the
distance from it) can be entered manually in a parameter (
90.58 Pos counter init
value int ), or taken from another parameter. This position is set as the value of the
position counter ( 90.07 Load position scaled int ) when the source selected by 90.67
Pos counter init cmd source , such as a proximity switch connected to a digital input, is
activated. A successful initialization is indicated by bit 4 of 90.35 Pos counter status .
-2147483 8
+2147483
(Proximity switch) Source set by 90.67
1
0
1
0
1
0
1
0
1
0
1
0
(Initialization inhibit) Source set by 90.68
90.35 Pos counter status
bit 4, Pos counter init ready
(Re-init request) Source set by 90.69
Drive fault
90.07 Load position scaled int
(Initial value) Source set by 90.59
(by default, 90.58 )
90.35 Pos counter status
bit 5, Position counter re-init disabled
0