Danfoss VLT5000 SyncPos Operating Instructions Manual page 139

■ ■ ■ ■ ■ PI D
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
timer
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 Limit)
i
Timer controller sample time
The corresponding factors can be set with the
following commands:
SET PID KPROP 1
SET PID KDER 1 /* set kd 1 */
SET PID KINT 0
SET PID KILIM 0 /* Integration limit 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
138
*∑e(n) ) /
i
/* set kp 1 */
/* set ki 0 */
/* Sample time = 1 */
Programmable SyncPos motion controller
■ ■ ■ ■ ■ POSA
The axis can be moved to a position absolute
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 position result
refers to this zero point.
NB!
If an acceleration and/or velocity has not been
defined at the time of the POSA command,
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
O RIG I N
Parameter: POSFACT_N (26), POSFACT_Z (23)
Syntax-Example
POSA 50000 /* move axis to position 50000 */
Program sample
PO S_01.M
MG. 1 0.J8.02 – VLT is a registered Danfoss trade mark