Danfoss FC Series VFD Reference Handling
There are some distinct differences in the handling and setup of reference signals in the FC series drives
when compared to legacy products. This tutorial will explain how to interpret the reference parameters
and achieve the desired results.
The first step in the setup requires you to setup parameters in the 3-0 parameter group and enter your
desired minimum and maximum references, which can be entered in parameters 3-02 & 3-03. No
matter which reference unit you will be working in, these are the lowest and highest allowable values to
be commanded to the VFD.
Next, you must understand the relevance of parameter 3-04. There are two available choices here,
“Sum” & “External / Preset”
When “Sum” is selected, any terminal programmed as a reference resource, including digital inputs,
analog inputs, preset references or serial bus references will be added together to produce the total
allowable “Maximum Reference” set in parameter 3-03. Each of these different possible reference
resources can be scaled to produce a certain percentage of the maximum.
When “External / Preset” has been selected, the drive will respond to either only preset references, OR
the sum of all the external reference resources as described above. The drive will toggle between the two
through the use of a digital input, as shown below……..
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