Danfoss VLT 5000 Series Manual page 102

I I I I I PID
A PID filter can be calculated with this function. The
PID filter works according to the following formula:
u(n) = ( k * e(n) + k *(e(n)-e(n–1)) + k
p d
where the following is true:
e(n) error occurring at time n
k proportional factor of the PID control
p
k derivative factor
d
k integral factor (limited by Integration
i
Limit)
Timer controller sample time
The corresponding factors can be set with the
following commands:
SET PID KPROP 1
SET PID KDER 1
SET PID KINT 0
SET PID KILIM 0
SET PID TIMER 1
The following syntax examples which also show the
default allocation of the factors.
Summary
calculates PID filter
Syntax
u(n) = PID e(n)
Parameter
e(n) = actual deviation (error) for which the PID filter
should be used
Return value
u(n) = result of the PID calculation
Command group
I/O
Syntax-Example
e = INAD 53
u = PID e
PRINT "input = ",e, "output = ",u
102
*∑e(n) ) / timer
i
/* set kp 1 */
/* set kd 1 */
/* set ki 0 */
/* Integration limit 0 */
/* Sample time = 1 */
VLT ® 5000 SyncPos option
I I I I I POSA
The axis can be moved to a position relative to the
actual zero position.
When the POSA command exceeds the software
limit switch NEGLIMIT (4) or POSLIMIT (5) the
program continue with the next command after an
error.
Summary
Positioning in relation to actual zero point
Syntax
POSA p
Parameter
p = Position in user units (UU) absolute to the
actual zero point; the UU corresponds in the
standard setting the number of Quadcounts.
NB!
If a temporary zero point, set via SET
ORIGIN, exists and is active, then the posi-
tion result refers to this zero point.
NB!
If an acceleration and/or velocity has not
been defined at the time of the POSA com-
mand, then the procedure will take place with the
values of parameter DFLTVEL (33) and DFLTACC
(34).
Command group
ABS
Cross Index
VEL, ACC, POSR, HOME, DEF ORIGIN, SET
ORIGIN
Parameter: POSFACT_N (26), POSFACT_Z (23)
Syntax-Example
POSA 50000 /* move axis to position 50000 */
Program sample
POS_01.M
MG.10.J4.02 – VLT is a registered Danfoss trade mark