Miller Electric S-21E - Manual (Page 16)

B. SpotlBurnback Time Control Option (Diagram
7-2)
1. Optional Spot/Burnback Board PC2 provides
control of spot weld time and adjustment of burn-
back time.
2. Burnback potentiometer R26 allows adjustment
of the burnback time between 0.02 and 0.25 sec-
onds.
3. Spot time potentiometer R25 allows adjustment
of spot time from 0.12 to 2.5 seconds or 0.25 to 5
seconds depending on the setting of Spot Time
DIP Switch Sl.
4. Spot/Continuous switch S51 allows either a nor-
mal untimed weld cycle or a timed spot weld
cycle.
5. Spot time DIP switch 51 provides a selection of
short range (0.12 to 2.5 seconds) or long range
(0.25 to 5 seconds) spot time.
Diagram 7-2. Block Diagram For Spot/Burnback Time Control Option
TM-1571 Page 12 S-21E