924VHE4.02 -
VEH
series humidifiers
02/2022
| 31 |
9.3.1 Available Modbus commands and data areas
The commands implemented are as follows:
Command
Description
03 (hex 0x03)
Resource reading command
06 (hex 0x06)
Resource writing command
9.4 Address configuration
TheRS-485communicationserialportcanbeusedtoconfigurethedevice,theparameters,thestatusesandtheModbus
variables and to monitor device operation using Modbus protocol.
The address of a device within a Modbus message is set by the
MODBUS Address
parameter.
The address
0
isonlyusedforbroadcastmessages,recognisedbyallslaves.Slavedevicesdonotrespondtoabroadcast
message.
Seriallineconfigurationparameters,whichcanbeaccessedviatheuserinterfacemenu,are:
Par.
Description
MU
Range
Default
MODBUS Address
Modbus protocol controller address.
---
0...255
1
MODBUS Speed
Modbus transmission speed (baud rate).
1200
= 1200 baud;
2400
= 2400 baud;
4800
=4800baud;
9600
=9600baud;
19200
=19200baud;
38400
=38400baud;
56000
= 56000 baud;
115200
= 115200 baud.
Baud
1200 / 2400 /
4800/9600/
19200/38400/
56000 / 115200
19200
TheRS-485RTUseriallinehasthefollowingcharacteristics(whichcannotbechanged):
• RTU mode:
• Parity: No parity (none);
•
Bit:8bit
• Stop bit: 1 bit.
9.5 Connections
Fortheentiresystemtoworkproperly,includingtheRS-485RTUserialline,observetheinstructionsprovidedinchapter
"6. ELECTRICAL CONNECTIONS" ON PAGE 20
.
Inparticular,makesuretheconnectionsareperformedcorrectly,observingtheinstructionsinsection
"6.3 WIRING DIAGRAM" ON PAGE 24
.
9.6 Modbus tables content
Table content description
The table below contains the information required to access the resources properly and directly.
There is a table:
•
Modbusaddresstable,whichcontainsalltheconfigurationparametersforthedeviceandthecorrespondingModbus
addresses.
Description of columns in the Table of addresses
• Par
.:Listofconfigurabledeviceparameters;
• Description
: Indicates parameter operation and any possible selections;
• MU
: Measurement unit relating to the parameter;
• Range
: Describes the interval of values that the parameter can assume. This can be correlated with other instrument
parameters (indicated with the parameter code).
NOTE
:
if the actual value is outside the permitted limits for that parameter (for example, because other parameters
defining the aforementioned limits have been altered), the value of the violated limit is displayed instead of the actual
value;
• Addr.
Val.
: Indicates the address of the Modbus register containing the resource you want to access;
•
R/W:
Indicates the option of reading or writing the resource:
• R
: The resource is read-only;
• W
: The resource is write-only;
•
R/W
: The resource can be both read and written.
• CPL
:WhenthefieldsindicatesY,thevaluereadbytheregisterneedstobeconvertedbecausethevaluerepresentsa
number with a sign. In the other cases the value is always positive or zero.
• DATA SIZE
: Indicates the size in data bits:
• WORD
= 16 bit
• Byte
=8bit
• The “
n
” bits = 0...15 bit depending on the value of “n”
