Process Words (Pcd); Examples - Danfoss VLT Micro Drive PK18 Design Manual

RS485 Installation and Set-...
Serial communication is only capable of reading
parameters containing data type 9 (text string).
15-40 FC Type to 15-53 Power Card Serial Number contain
data type 9.
For example, read the unit size and mains voltage range in
15-40 FC Type. When a text string is transferred (read), the
length of the telegram is variable, and the texts are of
different lengths. The telegram length is defined in the
second byte of the telegram (LGE). When using text
transfer, the index character indicates whether it is a read
or a write command.
To read a text via the PWE block, set the parameter
command (AK) to 'F' Hex. The index character high-byte
must be "4".
8.4.11 Data Types Supported by the
Frequency Converter
8 8
Unsigned means that there is no operational sign in the
telegram.
Data types
3
4
5
6
7
9
8.4.12 Conversion
The various attributes of each parameter are displayed in
the section Factory Settings. Parameter values are
transferred as whole numbers only. Conversion factors are
therefore used to transfer decimals.
4-12 Motor Speed Low Limit [Hz] has a conversion factor of
0.1.
To preset the minimum frequency to 10Hz, transfer the
value 100. A conversion factor of 0.1 means that the value
transferred is multiplied by 0.1. The value 100 is thus
perceived as 10.0.
74
VLT Micro Drive Design Guide
Description
Integer 16
Integer 32
Unsigned 8
Unsigned 16
Unsigned 32
Text string
®
MG02K102 - VLT is a registered Danfoss trademark
Conversion index
74
2
1
0
-1
-2
-3
-4
-5

8.4.13 Process Words (PCD)

The block of process words is divided into two blocks of
16 bits, which always occur in the defined sequence.
PCD 1
Control telegram (master⇒ slave Control
word)
Control telegram (slave ⇒ master) Status
word

8.5 Examples

8.5.1 Writing a Parameter Value
Change 4-14 Motor Speed High Limit [Hz] to 100Hz.
Write the data in EEPROM.
PKE = E19E Hex - Write single word in 4-14 Motor Speed
High Limit [Hz]:
IND = 0000 Hex
PWEHIGH = 0000 Hex
PWELOW = 03E8 Hex
Data value 1000, corresponding to 100Hz, see
8.4.12 Conversion.
The telegram looks like this:
E19E H 0000 H 0000
PKE IND PWE
Note: 4-14 Motor Speed High Limit [Hz] is a single word, and
the parameter command for write in EEPROM is "E".
Parameter number 4-14 is 19E in hexadecimal.
The response from the slave to the master is:
Conversion factor
0.1
100
10
1
0.1
0.01
0.001
0.0001
0.00001
PCD 2
Reference-value
Present output
frequency
H 03E8 H
PWE
high low