Danfoss VLT Profinet MCA 120 Operating Instructions Manual page 32

How to Control the Frequenc...
Depending on the setting of 3-00 Reference Range the
reference and MAV are scaled accordingly:
6 6
Illustration 6.2 Scaled MAV
NOTICE
If 3-00 Reference Range is set to [0] Min - Max, a negative
reference will be handled as 0%.
The actual output of the frequency converter is limited by
the speed limit parameters in 4-11 Motor Speed Low Limit
[RPM] to 4-14 Motor Speed High Limit [Hz].
The final speed limit is set by 4-19 Max Output Frequency.
The reference and the MAV have the format which appears
in Table 6.11.
MRV/MAV
100%
75%
50%
25%
0%
-25%
-50%
-75%
-100%
Table 6.11 The Format of Reference and the MAV
NOTICE
Negative numbers are formed as two's complement.
NOTICE
The data type for MRV and MAV is a N2 16 bit
standardised value, meaning it can express a range from
-200% to +200% (8001 to 7FFF).
30
Operating Instructions
Integer in hex Integer in decimal
4000 16.384
3000 12.288
2000 8.192
1000 4.096
0 0
F000 -4.096
E000 -8.192
D000 -12.288
C000 -16.384
Danfoss A/S © Rev. 2014-02-27 All rights reserved.
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
0% 0 hex
25% 1000 hex
50% 2000 hex
75% 3000 hex
100% 4000 hex
Table 6.12
6.3.4 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.
- MRV represents the process setpoint.
- MAV expresses the actual process feedback (range
±200%).
6.3.5 Influence of the Digital Input
Terminals upon FC Control Mode,
8-50 Coasting Select to 8-56 Preset
Reference Select
The influence of the digital input terminals upon control of
the frequency converter can be programmed in
8-50 Coasting Select to 8-56 Preset Reference Select.
NOTICE
The 8-01 Control Site overrules the settings in
8-50 Coasting Select to 8-56 Preset Reference Select, and
Terminal 37 Coasting Stop (safe) overrules any parameter.
Each of the digital input signals can be programmed to
logic AND, logic OR, or to have no relation to the
corresponding bit in the control word. In this way a
specific control command that is, stop/coast, can be
initiated by fieldbus only, fieldbus AND Digital Input, or
Ether Fieldbus OR Digital input terminal.
CAUTION
In order to control the frequency converter via
PROFINET, 8-50 Coasting Select must be set to either [1]
Bus, or to [2] Logic AND, and 8-01 Control Site must be
set to [0] or [2].
More detailed information and examples of logical
relationship options are provided in chapter 10 Trouble-
shooting.
Actual speed
100 RPM
825 RPM
1550 RPM
2275 RPM
3000 RPM
MG90U302