Fidelix FX-RP multiDISPLAY
Programming manual
page 27 of 38
Modbus master functionality
To use the FX-RP multiDISPLAY as a Modbus master, the correct type of pointID must be used in the graphics
editor. Point names starting with “MODBUS” are detected as Modbus master definition. The pointID should also
contain fields for Modbus address, register number, Modbus device type and register format. A pointID
containing all needed information looks something like this:
“MODBUS:ADD=1:REG=0:TYPE=INPUT:FORMAT=INT16”.
field
description
options
ADD
Modbus device
address
value between
1-247
REG
Register number
(starting from 0)
value between
0-65535
TYPE
Modbus device
type
INPUT
HOLDING
SINGLEREG
DISCRETE
COIL
read-only register
read-write register
write single register
read-only Boolean
read-write Boolean
FORMAT Register format
defines how the
value is
presented in
registers
INT16
UINT16
INT32
UINT32
REV_INT32
REV_UINT32
FLOAT
REV_FLOAT
BITMASK;xxxx
signed single register
unsigned single register
signed dual register
unsigned dual register
signed dual register with reversed register order
unsigned dual register with reversed register order
IEEE 754 dual register single precision floating point
IEEE 754 dual register single precision floating point with
reversed register order
bitmask operation for register, bitmask is presented in
hex format and it can contain one or more bits set
Example: BITMASK;0020 means the 6
th
bit
In addition to these settings some serial settings and other communication related settings are needed. Those
are defined in a text file named “ModbusMasterSettings.txt” which should be located in your project folder. If the
file is not found or the definitions file is invalid, default settings are used (57600, 8N1, 50ms send delay, 100ms
timeout, AUTO generated combined modbusdevices). There are example projects with the correct syntax used
for the Modbus master feature available in the Demo projects folder. The settings in the file are explained in the
following table. The term “modbusdevice” is used as the name for a zone of registers towards which a
communication socket is opened by the Modbus master display.
field
Options (or example) description
BAUD
9600
19200
38400
57600
115200
communication baud rate
BITS
8n1
8e1
8o1
8n2
8e2
8o2
data bits, parity and stop bits
SENDDELAY
numeric value
Send delay before new request in milliseconds. The timer
is started when a reply has been received or when the
timeout timer has ran out.
