Instruction manual

Instruction Manual
- 26 -
6.3.3 Stitch Correction and Speed Release
Function with or without control panel
Parameter
Stitch correction time
Delay until speed release after start backtack
(t8)
(t1)
150
200
Speed release after single and double backtack can be influenced by parameter 200 .
In the case of slow backtack mechanisms it is possible to delay disabling of the stitch regulator in the single and
double start backtack by the time t8 (start backtack stitch correction) and thereby prolong the backward section.
This time-lag can be selected by means of parameter 150.
6.3.4 Double start backtack
The forward section will be sewn for a number of stitches that can be set. Then the stitch regulator signal will be
issued and the backward section will be executed. The number of stitches for the two sections can be set
separately.
6.3.5 Single start backtack
A configurable stitch count is used to give the backtack signal and finish the backward section.
6.4 End backtack
Function without control panel
Control
Single end backtack
Double end backtack
End backtack Off
Segment 3 on
Segment 4 on
Both segments off
key + (S3)
Function with control panel
V810
V820/V850
Single end backtack
Double end backtack
End backtack Off
left-hand arrow above key On
right-hand arrow above key On
both arrows Off
Key 2
Key 4
Function with or without control panel
Parameter
Stitch length during backtack
Speed for end backtack can be interrupted by pedal 0
Start and end backtack can be interrupted by pedal in pos. 0
(SLu)
(n2E)
(StP)
137
126
284
The end backtack starts either by heelback, by a seam with stitch counting at the end of counting, o, from the
light barrier seam at the end of the light barrier compensating stitches. The stitch regulator is immediately
enabled from machine standstill.
After lowering the sewing foot, the switch-on point of the signal is delayed by the time t3 (start delay after
switching off the sewing foot lifting signal). The first leading edge of position 1 counts as 0 stitch whenever the
function is not started in position 1. The counting and turning off of the stitch regulator is synchronized at
position 1.
From full machine run, end backtack will be switched in only after having reached the speed n4 and
synchronization to position 1.
Parameter 284 can be used to determine whether an interruption of the start and end backtack is permitted. For
ornamental backtacks parameter 284 has no effect.
284 = 0
The backtacks run automatically and are not interruptible.
284 = 1
The backtacks can be interrupted by returning the pedal to 0. For this setting, the speed
setting of parameter 125 applies.
After an interrupted end backtack, the pedal can be pushed forwards to
continue the backtack; pedal position –1 lifts the sewing foot, or pedal position –2
ends the trimming process without an end backtack. Automatic lifting of the sewing foot does not
take place if the backtack is interrupted.