Danfoss LonWorks Option Card, Instruction Manual

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VLT
®
5000 / VLT
®
6000 HVAC / VLT
®
8000 AQUA
A controller node can monitor or modify any
VLT parameter by supporting the
Parameter
access command and the Parameter access
response functions. These functions allow a
controller complete access to the features of
the VLT and the ability to configure drives with
predefined settings, using the network
variables nviParamCmd and nvoParamResp.
The following definitions describe how the
fields of SNVT_preset are used by the VLT
LonWorks option:
Learn
This field contains the function code for the
VLT. The values for this field are:
LN_RECALL (0),
LN_LEARN_CURRENT (1),
LN_LEARN_VALUE (2), and
LN_REPORT_VALUE (3).
LN_RECALL (0) and
LN_REPORT_VALUE (3)
are interpreted as read commands.
LN_LEARN_CURRENT (1) and
LN_LEARN_VALUE (2)
are interpreted as write commands.
Any other value in this field will result in an
error message in the
Parameter access
response.
Selector
This field contains the VLT parameter
number, written in decimal notation, that is
to be written or read. Requests for
undefined parameters will result in an error
message in the
Parameter access esponse.
VLT
Parameter
Access The controlling device should compare the
parameter number of the response
message to the requested parameter
number to determine that the information
received is the requested information and
not a response to another controller or from
another VLT.
Value
This array contains the parameter
information to and from the VLT. All VLT
parameters use 16 bit signed or unsigned
values. The most significant 2 hex bytes of
data will be stored in value [0] and the least
significant 2 hex bytes of data will be stored
in value [3]. In the event of an error
message, the VLT will send 0xff in value [0]
and an error code in value [3]. The error
codes are defined in the section
Parameter
Access Error Codes in this manual.
NOTE
Consult Conversion Index in
the VLT Instruction Manual
parameter table for correct
conversion factor for reading and
writing to and from drive.
Day, Hour, Minute, Second, Millisecond
The time fields are not supported by the
VLT LonWorks option. The VLT will respond
to parameter access requests as soon as
they are received. Any values in the time
fields of the
Parameter access command
will be ignored. All time fields will be set to
“0” in the
Parameter access response.
Function SNVT type Variable Name
Parameter access command SNVT_preset nviParamCmd
Network Variable Output from VLT
Network Variable Input to VLT
Function SNVT type Variable Name
Parameter access response SNVT_preset nvoParamResp