Specifications
IP 240 Positioning
10.6 Backlash Compensation (LOSE)
Backlash in the position decoding system reduces the positioning accuracy. To prevent this, all
positions and the reference point must always be approached from the same direction. The IP 240
supports this when you configure ”Backlash compensation”.
Configuring backlash compensation
You can specify backlash compensation by setting the ”LOSE” parameter to ”1”:
: JU FB 167
NAME : STRU.POS
:
:
LOSE : KF x x=0 No backlash compensation; the direction of movement is not to
be evaluated when range BEE2 is entered.
x=1 Backlash compensation; the direction of movement is to be
evaluated when range BEE2 is entered.
10.6.1 Backlash Compensation during Positioning
When you configure ”LOSE”=1, you stipulate that positions may be approached in a positive
direction only (ascending actual value).
To determine the direction of travel, the change in the actual value on entering range BEE2 is
computed on the IP 240 over a module firmware cycle. If the IP identifies a positive direction of
travel, positioning proceeds normally.
If the IP identifies a negative direction of travel,
• the IP output is not reset.
• interrupts BE2 (range BEE2 entered) and BE3 (range BEE3 entered) are not generated.
• status bit ZBEV is not set and the associated interrupt ZBV is not generated when the target
range (range BEE3) is exited.
When range BEE2 is exited, the IP 240 indicates that the position can be reselected by setting
status bit RIUM and generating interrupt RIU.
If the direction of travel changes to negative after range BEE2 has been entered, the status and
interrupt bits are not affected (ZBEV is not set; interrupts BE2, BE3 and ZBV are not generated).
Note
Backlash compensation does not affect the setting and resetting of status bits BEE1,
BEE2 and BEE3.
When the position has been ”overrun”, the IP 240 signals that range BEE2 has been
exited. The IP output that is still active can be disabled via the STEP 5 program by
setting the FREI control bit to ”0” and forwarding it to the IP 240 ( Section 10.15.1
”Controlling the IP Outputs”).
EWA 4NEB 811 6120-02a
10-21