Reference Handling - Danfoss VLT Refrigeration Drive FC 103 Design Manual

Product Overview
[Hand On] Parameter 3-13 Reference
[Auto On] Site
LCP Keys
Hand Linked to Hand/Auto
Hand⇒Off Linked to Hand/Auto
Auto Linked to Hand/Auto
Auto⇒Off Linked to Hand/Auto
All keys Local
All keys Remote
Table 2.3 Local and Remote Reference Configurations
MG16G202
Design Guide

2.4.4 Reference Handling

Active Reference
Reference handling is applicable in both open- and closed-
Local
loop operation.
Local
Remote
Internal and external references
Remote
Up to 8 internal preset references can be programmed into
the frequency converter. The active internal preset
Local
reference can be selected externally through digital control
Remote
inputs or the serial communications bus.
External references can also be supplied to the frequency
converter, most commonly through an analog control
input. All reference sources and the bus reference are
added to produce the total external reference. As active
reference select one of the following:
•
•
•
•
The active reference can be scaled.
The scaled reference is calculated as follows:
Reference = X + X ×
Where X is the external reference, the preset reference, or
the sum of these references, and Y is parameter 3-14 Preset
Relative Reference in [%].
If Y, parameter 3-14 Preset Relative Reference, is set to 0%,
the scaling does not affect the reference.
Remote reference
A remote reference is comprised of the following (see
Illustration 2.12):
•
•
•
•
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The external reference
The preset reference
The setpoint
The sum of all the above 3
Y
100
Preset references
External references:
- Analog inputs
- Pulse frequency inputs
-
Digital potentiometer inputs
- Serial communication bus references
A preset relative reference
A feedback controlled setpoint
2 2
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