Process Words (Pcd); Examples; Writing A Parameter Value; Reading A Parameter Value - Danfoss VLT Midi Drive FC 280 Design Manual

RS485 Installation and Set-...
Conversion index
74
2
1
0
-1
-2
-3
-4
-5
Table 5.9 Conversion

5.4.13 Process Words (PCD)

The block of process words is divided into 2 blocks of 16
bits, which always occur in the defined sequence.
PCD 1
Control telegram (master⇒slave control word) Reference value
Control telegram (slave⇒master) status word
Table 5.10 Process Words (PCD)

5.5 Examples

5.5.1 Writing a Parameter Value

Change parameter 4-14 Motor Speed High Limit [Hz] to 100
Hz.
Write the data in EEPROM.
PKE = E19E hex - Write single word in
parameter 4-14 Motor Speed High Limit [Hz]:
•
IND = 0000 hex.
•
PWEHIGH = 0000 hex.
•
PWELOW = 03E8 hex.
Data value 1000, corresponding to 100 Hz, see
chapter 5.4.12 Conversion.
The telegram looks like Illustration 5.9.
E19E H 0000 H 0000
PKE IND PWE
Illustration 5.9 Telegram
MG07B102
Design Guide
Conversion factor
3600
100
10
1
0.1
0.01
0.001
0.0001
0.00001
PCD 2
Present output
frequency
H 03E8 H
PWE
high low
Danfoss A/S © 03/2016 All rights reserved.
NOTICE
Parameter 4-14 Motor Speed High Limit [Hz] is a single
word, and the parameter command for write in EEPROM
is E. Parameter 4-14 Motor Speed High Limit [Hz] is 19E in
hexadecimal.
The response from the slave to the master is shown in
Illustration 5.10.
119E H 0000 H 0000
IND PWE
PKE
Illustration 5.10 Response from Master

5.5.2 Reading a Parameter Value

Read the value in parameter 3-41 Ramp 1 Ramp Up Time.
PKE = 1155 hex - Read parameter value in
parameter 3-41 Ramp 1 Ramp Up Time:
•
IND = 0000 hex.
•
PWE = 0000 hex.
HIGH
•
PWE = 0000 hex.
LOW
1155 H 0000 H 0000
PKE IND
Illustration 5.11 Telegram
If the value in parameter 3-41 Ramp 1 Ramp Up Time is 10
s, the response from the slave to the master is shown in
Illustration 5.12.
1155 H 0000 H 0000
PKE
IND
Illustration 5.12 Response
3E8 hex corresponds to 1000 decimal. The conversion
index for parameter 3-41 Ramp 1 Ramp Up Time is -2, that
is, 0.01.
Parameter 3-41 Ramp 1 Ramp Up Time is of the type
Unsigned 32.
H 03E8 H
PWE
low
high
H 0000 H
PWE PWE
high low
H 03E8 H
PWE PWE
high low
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