Watson-Marlow MM420 - Manual (Page 134)

3 Functions Issue 10/06
MICROMASTER 420 Operating Instructions
134 6SE6400-5AA00-0BP0
3.12.2 Ramp-function generator (RFG)
Parameter range: P1120, P1121
r1119, r1170
P1130 – P1142
Function chart number: FP5000, FP5300
The ramp-function generator is used to limit the acceleration when the setpoint
changes according to a step function. This therefore helps to reduce the stressing
on the mechanical system of the machine. An acceleration ramp and a braking
ramp can be set independently of one another using the ramp-up time P1120 and
the ramp-down time P1121. This allows a controlled transition when the setpoint is
changed (refer to Fig. 3-52).
Without roun
ding
t
f
f
max
P1120 P1121
f
2
f
1
f
f
max
P1133 P1132 P1131 P1130 t
f
2
f
1
t
up
t
down
With ro
undin
g
for P1131) P1130 (
2
1
P1120
P1082
f - f
1 2 + ≥ ⋅
P1120
P1082
f - f
P1131) P1130 (
2
1
t
1 2
up
⋅ + + =
for P1133) P1132 (
2
1
P1121
P1082
f - f
1 2 + ≥ ⋅
P1121
P1082
f - f
P1133) P1132 (
2
1
t
1 2
down
⋅ + + =
Where the rounding times are increased to be greater than the ramp period then the ramp
period is determined by the following equations:
( )
( )
( ) ⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
+ ⋅
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
+ ⋅
⋅ ⋅ − ⋅
=
1130 P
1131 P
1
1131 P 1130 P f
1130 P 1120 P f f 2
t
max
2
1 2
up
( )
( )
( ) ⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
+ ⋅
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
+ ⋅
⋅ ⋅ − ⋅
=
1132 P
1133 P
1
1133 P 1132 P f
1132 P 1120 P f f 2
t
max
2
1 2
down
Fig. 3-52 Ramp-function generator