Jack C4 Training Courseware page 27

Operating Instructions –
Introduction for quick switch adjustment of avoid-cutting sensor
Long press key 3S, avoid-cutting sensor switch
quickly change, avoid-cutting sensor is turned on by
default, avoid-cutting sensor delay stitches (P50)
defaults to 0. (If the P50 item saves the parameter
value change, the P50 item parameter is equal to the
user saves the parameter value). When the avoid-
cutting sensor is turned off by default, the post-
sensor delay stitches (P28) defaults to 8. (If P28 items
save the parameter value change, then the P28
parameter is equal to the user to save the parameter
value)