Specifications

AP - 6 Applications Ver. 0002
AP.1.1.2.2 On spindle drives in open loop.
The CNC 50/55 indicates to the spindle drive, through the Sercos ring, the desired motor
speed in rpm (MS) which is calculated as follows:
To properly setup the drive, proceed as follows:
At the Drive:
- Set parameters SP20 -F00031- and SP21 -F00081- with the maximum motor speed
for this application and 9500 millivolts respectively.
- Set NP121 -S00121-, NP122 -S00122- and NP123 -S00123- when wishing to display
the tool speed on the screen while working with SERCOSLE=1.
At the CNC 50/55:
- Set the CNC 50/55 MAXGEARn parameters with the maximum tool speed for that gear
"n".
- Set the MAXVOLTn parameters according to the following equation:
Example of open loop spindle
A machine has three gear ratios: 4/1, 2/1 and 1/1. The maximum motor speed is 4000
rpm and the maximum tool speeds are: 1000, 2000 and 3800 rpm in each.
Therefore, proceeding as indicated earlier:
SP21 -F00081- = 4000, and
SP20 -F00031- = 9500.
MAXGEAR1 = 1000 rpm,
MAXGEAR2 = 2000 rpm, and
MAXGEAR3 = 3800 rpm.
The MAXVOLTn parameters
will be:
Feedback parameter setting at the spindle drive in open loop:
With SERCOSLE=0
Using external feedback requires all the feedback parameters to be set at the CNC 50/55:
NPULSES (P013), DIFFBACK (P014), FBACKAL(P015) and REFPULSE (P032).
With SERCOSLE=1
The Drive indicates the motor speed to the CNC 50/55 by means of digital commands
through Sercos. Therefore, the feedback characteristics will be set by the parameters of
the Drive. At the CNC 50/55, the parameters mentioned earlier are ignored.
MS ProgrammedSpeed
MAXVOLTn
MAXGEARn
mV
SP21
SP20
(motor rpm)=⋅⋅
1244444 344444
MAXVOLTn MAXGEARn Ratio
motor rpm
SP20
SP21
(mV)
Ratio = Gear Ratio =
N motor
N tool
=⋅⋅
124443444
MAXVOLT1 1000
4
1
9500
4000
(mV) = 9500 mV
MAXVOLT2 2000
2
1
9500
4000
(mV) = 9500 mV
MAXVOLT3 3800
1
1
9500
4000
(mV) = 9025 mV
=⋅⋅
=⋅⋅
=⋅⋅