Danfoss VLT PROFIBUS DP MCA 101, Руководство по программированию

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The content of PCD 3 to PCD 10 is determined by the
settings in
parameter 9-16 PCD Read Configuration .
4.2.3 Reference Handling
The reference handling is an advanced mechanism that
sums up references from different sources, as shown in
Illustration 4.2 .
For more information on reference handling, refer to the
Design Guide of the relevant frequency converter.
Illustration 4.2 Reference
The reference, or speed setpoint, is sent via PROFIBUS and
is always transmitted to the frequency converter in
percentage format as integers represented in hexadecimal
(0-4000 hex).
The reference (MRV) and feedback (MAV) are always scaled
equally. The setting of
3-00 Reference Range determines the
scaling of the reference and feedback (MAV), see
Illustration 4.3 .
Illustration 4.3 Reference (MRV) and Feedback (MAV), Scaled
NOTICE
When 3-00 Reference Range is set to [0] Min - Max , a
negative reference is handled as 0%.
The actual output of the frequency converter is limited by
the speed limit parameters
Motor Low/High Speed Limit
[RPM/Hz] in 4-11 Motor Speed Low Limit [RPM] to 4-14 Motor
Speed High Limit [Hz] .
The final speed limit is set in 4-19 Max Output Frequency .
Table 4.3 lists the reference (MRV) and the feedback (MAV)
formats.
MRV/MAV Integer in hex Integer in decimal
100% 4000 16,384
75% 3000 12,288
50% 2000 8,192
25% 1000 4,096
0% 0 0
-25% F000 -4,096
-50% E000 -8,192
-75% D000 -12,288
-100% C000 -16,384
Table 4.3 Reference/Feedback (MRV/MAV) Format
NOTICE
Negative numbers are formed as complement of 2.
NOTICE
The data type for MRV and MAV is a N2 16-bit
standardised value, expressing a range from -200% to
+200% (8001 to 7FFF).
Example
The following settings determine the speed, as shown in
Table 4.4 :
•
1-00 Configuration Mode set to [0] Speed open
loop .
•
3-00 Reference Range set to [0] Min-Max.
•
3-02 Minimum Reference set to 100 RPM.
•
3-03 Maximum Reference set to 3000 RPM.
MRV/MAV Actual speed [RPM]
0% 0 hex 100
25% 1000 hex 825
50% 2000 hex 1550
75% 3000 hex 2275
100% 4000 hex 3000
Table 4.4 Actual Speed for MRV/MAV
4.2.4 Process Control Operation
In process control operation, 1-00 Configuration Mode is set
to [3] Process .
The reference range in 3-00 Reference Range is always [0]
Min - Max.
Control Programming Guide
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