Examples; Example 1: Pcv Channel - Danfoss VLT 5000 Operating Instructions Manual

Example 1: PCV Channel

This example shows how PPO type 1 is used
for changing the ramp-up time (parameter 207)
to 10 seconds and for commanding a start
and speed reference of 50%.
PCD: Process Data
PCV: Parameter-Characteristics Value
PCA: Parameter-Characteristics (Bytes 1. 2)
PCA handling below
IND: Subindex (Byte 3), (Byte 4 is not used)
In the configuration of the PPO types (informative data
telegrams), a distinction is made between module
consistency and word consistency:
Module consistency means that a particular portion
of the PPO is defined as a connected module.
The parameter interface (PCV, length 8 byte) of the
PPO always has module consistency.
Word consistency means that a particular
portion of the PPO is divided into individual data
sectors of word size (16 bit).
PCV
PCA Parameter characteristics
RC: Request/Response
SPM: Toggle bit for spontaneous
messages
PNU: Parameter Number
PCA portion (byte 1-2)
The RC portion determines what the PCV
portion is to be used for.
If a parameter needs to be changed, value 2 or 3 must
be selected; here, 3 was selected since parameter
207 refers to a double word (32 bits).
SPM bit
In the example, the function "spontaneous
messages" is not needed (parameter 917 = OFF)
and thus the SPM bit is set to 0.
PNU = Parameter Number The parameter number
is set to: 207 = CF Hex. This means that the value
for the entire PCA portion is 30CF Hex.
IND (bytes 3-4)
This is used in reading/changing of parameters with
subindex, e.g. in the case of parameter 915. In the
example, the bytes 3 and 4 are set to 00Hex.
30
VLT® 5000/ 5000 FLUX/ 6000 HVAC/
8000 AQUA PROFIBUS
Frequency converter parameter settings:
P502: serial port
P512: Fieldbus profile (Profidrive profile) = factory setting
Please see section PPO description.
The process data (PCD) of the PPO can have either
module consistency or word consistency, as desired.
Some PLCs, such as the Siemens S7, require special
functions to address modules that are longer than 4 byte
(in the case of Siemens: "SFC", see Master Manual).
This means that, in the case of Siemens (S7), the
PCV interface of the PPOs can only be addressed
through the SFC functions.
PVA (bytes 5-8)
Changing the data value of parameter 207 to 10.00 s.
The transmitted value must be 1000, since the
conversion index for parameter 207 is -2, i.e. the value
(Range: 0-15)
received by the frequency converter is divided by 100
so that the frequency converter "understands" 1000
as 10.00. 1000 corresponds to 03E8Hex.
(Range: 1-990)
PCD (Process Data)
CTW (Control Word)
The following bit patterns set all necessary
start commands:
15 .... ...0 <=> Bit number
0 000 0100 0111 111 1 <=> 047FHex.
MRV (Main Reference Value)
Speed reference value, the data format is
"standardized value".
0Hex = 0% and 4000Hex = 100%.
For example, 2000Hex correspond to 50% of the
maximum frequency (parameter 202).
The entire PPO being sent from the master to
the frequency converter thus has the following
hexadecimal values:
PVA: Parameter value (Bytes 5 to 8)
CTW: Control word
STW: Status word
MRV: Main reference value
MAV: Main actual value
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