Parameter Access; Parameter Access In General; Dp-V1 Parameter Access - Danfoss VLT Midi Drive FC 280 Programming Manual

Parameter Access

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.
Parameter access from controllers and HMI
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
wanted set-up in parameter 0-11 Edit Set-up or
parameter 9-70 Edit Set-up.
Using the above-mentioned mechanism allows reading or
writing to and from parameters in a certain set-up from a
master class 1, for example a PLC. It is also possible to
access parameters simultaneously 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:
•
LCP.
•
FC Protocol on RS485 or USB.
•
Cyclic 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 when writing to parameters from an
HMI unit into a set-up actively in use by the frequency
converter or the process controller (for example 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,
use parameter 9-71 Profibus Save Data Values for storing 1
or more set-ups.
Using DP-V1 access, store parameters either in RAM or
non-volatile memory by selecting a specific write-request
command. At any time, store non-stored data in non-
volatile memory by activating parameter 9-71 Profibus Save
Data Values.
MG07F102
Programming Guide
5.1.2 Read/Write in Double Word Format
The special request IDs 0X51 (read) and 0X52 (write) allow
reading and writing 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 signaled by the telegram is 43h (dword).
5.1.3 PROFIBUS DP-V1
The acyclic DP-V1 transmission allows reading and writing
parameter values, as well as reading a number of
descriptive attributes for each parameter. Access to
parameters via DP-V1 is described in chapter 5.2 DP-V1
Parameter Access.
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 chapter 4.1 PPO
Types. 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 chapter 5.3 PCV
Parameter Access.
NOTICE
Object and data types common to both DP-V1 and PCV
parameter access are listed in chapter 5 Parameter Access.

5.2 DP-V1 Parameter Access

This section is useful for the developer with some
experience in:
•
•
For more detailed instructions on how to use the DP-V1
function, refer to the PROFIBUS master manual from the
PLC supplier.
Danfoss A/S © 05/2016 All rights reserved.
PLC programs with PROFIBUS master class 1
functionality.
PC applications with PROFIBUS master class 2
functionality.
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