4 position control parameters, 1 pnu 1894: velocity multiplier, 2 pnu 1807: axis type – BECKHOFF AX2000 PROFIBUS DP communication profile User Manual

Page 26: 5 position data for the position control mode, 1 pnu 1790: position, 2 pnu 1791: velocity, Axis type, Incremental position, Position data, Velocity

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4.2.4

Position control parameters

4.2.4.1

PNU 1894: velocity multiplier

This parameter is used to enter a multiplier for the jogging/homing velocity. In Positioning opmode,
the velocity for jogging/homing is set through PZD2 jogging/homing is started using bit 8/ bit 11 in
the control word (STW).
The actual jog velocity is calculated according to the following formula:

V

Bit

V

Bit

velocity multipli

Jog vel

Jog PZD

,

.

,

(

)

(

)

32

16

2

=

´

er

Bit

(

)

16

The default value for PNU 1894 is 1.

4.2.4.2

PNU 1807: axis type

This parameter is used to define the axis type.

Value

AX2500

AX2000

0

Linear axis

Linear axis

1

Rotary axis

Rotary axis

2

Modulo axis

Modulo axis

4.2.5

Position data for the position control mode

4.2.5.1

PNU 1790: position

Since the AX2000/2500 calculates all positioning operations internally only on an incremental basis,
there are limitations on the usable range of values for distances that are given in SI (user) units.
The range for the incremental position covers the values from -2

31

to (2

31

-1).

The resolution that is determined by the PGEARO (PNU1803 ind1) and PGEARI (PNU1802 ind1)
parameters and the variable PRBASE fix the sensibly usable range for positioning operations.
The variable PRBASE determines, through the equation n

PRBASE

= 2

, the number of increments per

motor turn. The value of PRBASE can only be 16 or 20.
PGEARO contains the number of increments that must be traversed when the distance to be
moved is PGEARI. The default values for PGEARO correspond to one turn.
The number of turns that can be covered are given as follows:
-2048..+2047 for PRBASE=16 and -32768..+32767 for PRBASE=20
The sensibly usable position range is derived as follows:

-

-

2

2

1

31

31

*

...(

) *

PGEARI

PGEARO

PGEARI

PGEARO

for PGEARI <= PGEARO or

-

-

2

2

1

31

31

...(

)

for PGEARI > PGEARO

4.2.5.2

PNU 1791: velocity

The usable range for the velocity is not limited by the available data area. It is limited by the maxi-
mum applicable speed nmax, which is given by the speed parameter VLIM as the final limit speed
for the motor.

The maximum velocity is thus given by:

n

SI

PRBASE

n

PGEARI

PGEARO

, max

max

=

´

´2

with n

max

in turns/second

or, in incremental units, as:

v

n

s

n

incr

PRBASE

PRBASE

. max.

max

max

sec

=

´

´

=

´

2

250

1

4000

2

m

with n

max

in turns/second

26

PROFIBUS for AX2000/2500

Using the parameter channel (PKW)

12/05

BECKHOFF

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