ABB ACQ550-U1-011A-6, Руководство пользователя

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ACQ550-U1 User’s Manual 191
Embedded fieldbus
Actual value scaling
The scaling of actual values can be protocol dependent. In general, for Actual
Values, scale the feedback integer using the parameter’s resolution. (See
Complete
parameter descriptions section for parameter resolutions.) For example:
Where parameters are in percent, the Complete parameter descriptions section
specifies what parameter corresponds to 100%. In such cases, to convert from
percent to engineering units, multiply by the value of the parameter that defines
100% and divide by 100%. For example:
1. Assuming, for the sake of this example, that the Actual Value uses parameter 9908
MOT NOM SPEED
as the 100% reference, and that 9908 = 1500 rpm.
2. Assuming, for the sake of this example, that the Actual Value uses parameter 9907
MOT NOM FREQ
as the 100% reference, and that 9907 = 500 Hz.
Scaling does not apply for the BACnet protocol.
Feedback
Integer
Parameter
Resolution
(Feedback Integer) * (Parameter Resolution) = Scaled Value
1 0.1 mA 1 * 0.1 mA = 0.1 mA
10 0.1% 10 * 0.1% = 1%
Feedback
Integer
Parameter
Resolution
Value of the
Parameter that
defines 100%
(Feedback Integer) * (Parameter Resolution) *
(Value of 100% Ref.) / 100% = Scaled Value
10 0.1% 1500 rpm
1
10 * 0.1% * 1500 RPM / 100% = 15 rpm
100 0.1% 500 Hz
2
100 * 0.1% * 500 Hz / 100% = 50 Hz