Technical data

Configuration
CPU 317T: Technology Functions
A5E00251798-03
4-35
Marginal conditions of the determination of gear parameters
The configuration may return error messages indicating inconsistent gear
parameters. Selection of the wrong configuration data may lead to internal
overflows in the integrated technology. You can define suitable parameters using
the following formula:
f
1 = measuring gear nominator • 360 • internal resolution • load gear nominator
f
2 = measuring gear nominator • encoder resolution • actual value coefficient •
nominator load gear nominator
Next, determine the greatest common divisor k of f
1 and f2, and place it into the
following formula:
f
11 = (f1/k) < 2exp32
f
22 = (f2/k) < 2exp32
The results of f
11 and f22 must be smaller than 2exp32. If this is not the case, check
whether you can reach values below maximum in f
11 and f22 by changing the
parameters in the formulae f
1 and f2.
If configuration errors persist, regardless whether f
11 and f22 satisfy requirements
as described earlier or not, check the following value:
f
3 = modulo length • internal resolution
You can now determine the greatest common divisor k
2 of f3 and f11, and the insert
it into the next formula:
f
31 = ((f3 • f22 • f11) / (k1 • k2)) < 2exp63
At this point, check whether the value in f
31 is lower than that in 2exp63. If not,
consider reducing the modulo length. You could also modify the parameters in the
f
1 and f2 formulae. When doing so, however, make sure that the conditions of f11
and f
22 are still satisfied.
Parameter description
Parameter Comments Axis configuration data
Measuring gear
nominator
Denominator of the measuring gear
ratio
AdaptDrive.numFactor
AdaptExtern. numFactor
AdaptLoad.numFactor
Measuring gear
nominator
Denominator of the measuring
gear ratio
AdaptDrive.denFactor
AdaptExtern. denFactor
AdaptLoad.denFactor
Load gear nominator Nominator of the load gear ratio Gear.numFactor
Load gear
denominator
Denominator of the load gear ratio Gear.denFactor
Internal resolution Internal increments / position unit Determined in the configuration by means
of the axis wizard.
Actual value
coefficient
= X with DP drive X with incremental encoder:
IncEncoder.incResolution MultiplierCyclic
X with absolute value encoder:
AbsEncoder.absResolution.MultiplierCyclic
A FAQ dealing with this issue and containing a corresponding calculation tool is
available on the Internet http://www.siemens.com/automation/service&support
.