5 Parameter Access
5.1 Parameter Access in General
In an automated system, frequency converter parameters
can be accessed either from the process controller (that is,
PLC), or from various kinds of HMI equipment. For
parameter access from controllers and HMI, observe the
following:
Parameters are located in 4 separate set-ups. Parameter
access in the frequency converter is performed via several
separated parameter channels. Use the separated channels
individually to access a certain parameter set-up. Select the
desired set-up in
0-11 Edit Set-up
or
9-70 Edit Set-up
.
Using the above mechanism it is possible to read or write
to and from parameters in a certain set-up from a master
class 1, for example a PLC. And it is also possible to
simultaneously access parameters in a different set-up
from a master class 2, for example a PC tool, without
interfering with the set-up selection for the programming
sources.
Parameters can be accessed via the following sites:
•
LCP
•
FC Protocol on RS485 or USB
•
Cyclical data access on DP-V0 (PCV Channel)
•
PROFIBUS Master Class 1
•
PROFIBUS Master Class 2 (3 connections possible)
NOTICE
Although the parameter channels are separated, data
conflict can occur if write to parameters is made from an
HMI unit into a set-up which is actively in use by the
frequency converter or the process controller (e.g. a
PLC).
5.1.1 Data Store
Parameters write via the PCV channel (DP-V0) is stored in
RAM only. If data has to be stored in non-volatile memory,
the
9-71 Profibus Save Data Values
can be used for storing
one or more set-ups.
Using DP-V1 access, store parameters either in RAM or
non-volatile memory by choice of a specific write-request
command. At any time, store non-stored data in non-
volatile memory by activating
9-71 Profibus Save Data
Values
.
5.1.2 Read/Write in Double Word Format
Using the special request IDs 0X51 (read) and 0X52 (write),
it is possible to read and write to all parameters containing
numeric values in a general format of double word. The
value element must be right aligned and unused MSBs
filled with zeros.
Example: Read of a parameter of type U8 is transmitted as
00 00 00 xx, where xx is the value to be transmitted. The
data type signalled by the telegram is 43h (dword).
5.1.3 PROFIBUS DP-V1
Using the acyclic DP-V1 transmission, it is possible to read
and write parameter values, as well as to read a number of
descriptive attributes for each parameter. Access to
parameters via DP-V1 is described in
5.1.4 PROFIBUS DP-V0/PCV Channel
Parameter access via the PCV channel is performed using
PROFIBUS DP-V0 cyclic data exchange, where the PCV
channel is part of the PPOs described in
. Using the PCV channel, it is possible to read and
write parameter values, as well as read a number of
descriptive attributes for each parameter. The functionality
of the PCV channel is described in
NOTICE
Object and data types common to both DP-V1 and PCV
parameter access are listed in
.
5.2 DP-V1 Parameter Access
This section is useful for the developer with some
experience in:
•
PLC programs with PROFIBUS master class 1
functionality.
•
PC applications with PROFIBUS master class 2
functionality.
For more detailed instructions in use of the DP-V1
function, refer to the PROFIBUS master manual from the
PLC supplier.
Parameter Access
Programming Guide
MG37G102
Danfoss A/S © Rev. 05/2014 All rights reserved.
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