Pigtronix Echolution-2 Deluxe - Manual (Page 14)

Expression Control
SHORT PRESS cycles between EXP control of:
R - Delay Repeats
T - Delay Time
M - Delay Mix
S - LFO speed
D - LFO depth
LONG PRESS turns on ENV MAP to EXP - this sums the
internal envelope follower with the current expression
pedal or on-board knob value for the chosen parameter,
allowing touch sensitive control over every knob.
When using the ENV MAP to EXP function, the position of
the expression pedal or onboard knob will be summed with
the envelope voltage.