Danfoss VLT 2800 Operating Instructions

FCM 300 / FCD 300 / VLT
®
2800 / DP V1 PROFIBUS
Read only parameters, as for example data read
out parameters, will not be registered as modified
eventhough they are changing.
When a 0 is returned as parameter number the list ends.
■ Read/write on frequency converter parameters
In an automation system, frequency converter
parameters can be accessed either from the Process
controller (i.e. PLC), or by various kinds of HMI
equipment. In order not to interfere access from
controllers and tools, the following should be taken
into consideration: Parameter acc ess in the drive is
performed in two logical parameter channels, which
can be individally programmed to access a certain
parameter setup via parameters 005 Programming
Setup and 970 Parameter setup selection. This
means, that before writing or reading to a parameter
in a certain frequency converter set-up from a PLC,
the parameter 970 must bne set to the desired
set-up. For acces s from HMI equipment, the access
is controlled by parameter 005. The figure below
shows this behaviour, and the possible sources of
the two logical parameter channels.
VLT frequency converter
A
ccess from process
control e.g. PLC:
- PCV channel (DP Vo)
-MSAC Master Class 1
A
ccess from HMI:
- Local Co ntrol Panel
- FC standard interface
- MSAC Master class 2
Please note, that even though these two logic al
parameter channels are separated, data conflict can
occour, if w rite on parameters is made from a HMI unit
into a set-up which is actively used by the frequency
converterorusedbytheprocesscontroller(e.g. PLC).
NB!:
For backward compability reasons the following
behaviour must be observed:
A Read or Write on parameter 970 via the MSAC
master class 2 connection will be accepted, but the
value will internally be read /written to parameter 005.
A Read or Write on parameter 005 via the process
controller channel will be ac cepted, but the value will
internally be read/written to parameter 970.
For parameter store, the following should be observed:
A Write command to a frequency converter parameter
via the MSAC Master class 2 co nnection will
be stored in RAM and in Non Volatile Memory.
Please note, that continuous writing to frequency
converter parameters via the MSAC Master class
2 connection s hould be avoided in order not to
damage the Non Volatile Memory.
A Write command to a frequency converter parameter
via the Process Control channel will be stored in RAM
only. Store in Non Volatile Mem ory is possible by writing
a store command to parameter 971 Save data values,
which w ill result in store of the entire set-up in NVRAM.
The table below shows how data write from various
sources are stored in the frequency converter:
Data source RAM NVRAM
PCV channel (DP V0) Yes Store set-up by parameter
971
MSAC Master Class 1 Yes Store set-up by parameter
971
Local Control Panel Yes Yes
MCT 10 software via FC
interface
Yes Yes
MCT10softwarevia
MSAC 2
Yes Yes
FC standard interface Yes Yes, by specific Write
command
MSAC Master Class 2 Yes Yes
MG.90.A5.02 - VLT is a registered Danfoss t rademark
38

Danfoss VLT 2800 Specifications

General

Brand	Danfoss
Model	VLT 2800
Category	DC Drives
Language	English