The SCADA node, including Windows CE version, will act as a Modbus Ethernet Slave Device (i.e. look like a PLC). This device emulation feature is usually used to:
communicate to older existing automation systems (for example an existing DCS which acts as a Modbus Master)
or
for remote sites using telemetry, radio or dial-up communications to slow to support TCP/IP communications between nodes.
By creating a MODDEF.INI file in the \WebAccess\node\Project_SCADANode\ folder, the SCADA node will respond to Modbus Master requests. (If this file is created on the project Node under \WebAccess\node\config\Project_SCADANode, it can be downloaded to the SCADA node during the next download).
The user must map tags to Modbus addresses in the MODDEF.INI.
An example MODDEF.INI is as follows:
[MOD_DEF]
LISTEN_PORT=504
TOTAL_TAG=7
TAG1=40001,TM_65,0
TAG2=40002,SIN_65,4
TAG3=40004,F65_CA01,4
TAG4=40014,F65_CA06,1
TAG5=30001,MD30001,0
TAG6=00001,F65_CD01,0
TAG7=10003,F65_CD_02_ALARM,0
LISTEN_PORT = port number for TCP/IP, must match Advantech WebAccess/SCADA device configuration, Default:504
TOTAL_TAG = Total tags to be read
TAGn=ModBus_Address,Advantech WebAccess_TagName,Type
n= 1 to total_tag
ModBus_Address = 0xxxx, 1xxxx, 3xxxx, 4xxxx
Type 0 = Unsigned 16-bit integer
Type 1 = Signed 16-bit integer
Type 2 = Unsigned 32-bit integer
Type 3 = Signed 32-bit integer
Type 4 = 32-bit Floating points.