The slack take-up function, 3 the slack take-up function – Rockwell Automation WebPak 3000 DC Drive Application Workbook Version 1.1 User Manual
Page 74

12-6
WebPak 3000 DC Drive Application Workbook, Version 1.1
þ
To set the
PI
block
HI
and
LO
limits:
▲
Set
TENSION
PI
LIMIT
(P.853). For example, if 10% tension vernier is to be used,
set the
PI
block
HI
and
LO
limits to 409 counts.
The output of the tension
PI
block provides a vernier signal that is used to trim
the speed loop reference when
OCL
TYPE
(P.818) is set to
CASCADE
and to trim
the speed loop
PI
limits when
OCL
TYPE
(P.818) is set to
PARALLEL
.
In cascade, 4095 counts equals top line speed. In parallel, 4095 counts
equals maximum current
.
þ
If the outer control loop is configured as a tension regulator
(P.817 =
TENSION
):
▲
Set
TEN
LEADLAG
SELECT
(P.837) to
LAG
/
LEAD
.
▲
Set
SPD
LOOP
PI
LEAD
FREQ
(P.212). Note that this value was set during
self-tuning.
▲
Set
TEN
OUT
LL
LOW
FREQ
(P.838) to twice the value of
SPD
LOOP
PI
LEAD
FREQ
(P.212).
▲
Set
TEN
OUT
LL
RATIO
(P.839) to 8.0.
12.3 The Slack Take-Up Function
The slack take-up function initiates a smooth removal of loose web when drive tension
is on by limiting the amount of motor torque applied until the slack is removed.
When slack take-up is released, the drive operates at the tension set by
TEN
RAMP
OUTPUT
(P.842).
Refer to figure A.19 in Appendix A of the software manual (D2-3444) as you configure
the tension
PI
limits for the slack take-up function.
þ
To use the slack take-up function:
▲
Set
SLACK
TENSION
PI
LIM
(P.318).
▲
Assert the slack take-up digital input (terminal 12 on the Regulator board).
(
SLACK
TAKE
UP
DIN
TP
(P.494) should be
ON
). The drive uses the value of
SLACK
TENSION
PI
LIM
(P.318), which is a percentage of the running limit value
as set by
TENSION
PI
LIMIT
(P.853).
þ
To turn off the slack take-up function:
▲
De-assert the slack take-up digital input (terminal 12 on the Regulator board).
(
SLACK
TAKE
UP
DIN
TP
(P.494) should be
OFF
).
Range: 0 to 4095
COUNTS
P.853 =
COUNTS
Range:
LEAD
/
LAG
,
BYPASS
,
LAG
/
LEAD
P.837 =
/$*/($'
Range: 0.00 to 141.37
RAD
/
S
P.212 =
RAD
/
S
Range: 0.01 to 139.62
RAD
/
S
P.838 =
RAD
/
S
Range: 2 to 20
P.839 =
Range: 0.0 to 100.0%
P.318 =
%