Danfoss VLT 6000 HVAC Profibus, Руководство пользователя

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VLT
®
6000 HVAC
115
MG.60.B1.02 - VLT is a registered Danfoss trade mark
★
= factory setting. ( ) = display text [ ] = value for use in communication via serial communication port
Programming
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PID overview
The block diagram below shows reference and
setpoint in relation to the feedback signal.
As can be seen, the remote reference is totalled with
setpoint 1 or setpoint 2. See also Reference handling
on page 61.
Which setpoint is to be totalled with the remote
reference depends on the selection made in
parameter 417 Feedback function .
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Feedback handling
The feedback handling can be seen from the block
diagram on the next page.
The block diagram shows how and by which
parameters the feedback handling can be affected.
Options as feedback signals are: voltage, current,
pulse and bus feedback signals. In zone regulation,
feedback signals must be selected as voltage inputs
(terminals 53 and 54). Please note that Feedback 1
consists of bus feedback 1 (parameter 535) totalled
with the feedback signal value of terminal 53.
Feedback 2 consists of bus feedback 2 (parameter
536) totalled with the feedback signal value of
terminal 54.
In addition, the VLT 6000 HVAC has an integral
calculator capable of converting a pressure signal into
a "linear flow" feedback signal. This function is
activated in parameter 416 Feedback conversion.
The parameters for feedback handling are active both
in closed and open loop modes. In open loop, the
present temperature can be displayed by connecting
a temperature transmitter to a feedback input.
In a closed loop, there are - roughly speaking - three
possibilities of using the integral PID regulator and
setpoint/feedback handling:
1. 1 setpoint and 1 feedback
2. 1 setpoint and 2 feedbacks
3. 2 Setpoints and 2 feedbacks
1 setpoint and 1 feedback
If only 1 setpoint and 1 feedback signal are used,
parameter 418 Setpoint 1 will be added to the remote
reference. The sum of the remote reference and
Setpoint 1 becomes the resulting reference, which
will then be compared with the feedback signal.
1 setpoint and 2 feedbacks
Just like in the above situation, the remote reference
is added to Setpoint 1 in parameter 418. Depending
on the feedback function selected in parameter 417
Feedback function , a calculation will be made of the
feedback signal with which the sum of the references
and the setpoint is to be compared. A description of
the individual feedback functions is given in parameter
417 Feedback function .
2 Setpoints and 2 feedbacks
Used in 2-zone regulation, where the function
selected in parameter 417 Feedback function
calculates the setpoint to be added to the remote
reference.