Modbus data references
- Last UpdatedJul 26, 2024
- 1 minute read
A Modbus point is defined by its outstation name, point type, point address, and optionally, point name. When adding points to an outstation, use the following general guidelines:
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All references begin with "Telem_Server_" prepended to the Scope Name.
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Modbus point addresses have 5 or 6 digits, depending on the Point Address Range setting of the outstation. The default setting is 5 digits. The range of valid addresses vary by point type.
Point types
A point in Modbus can be defined as any of the following types:
|
Point type |
I/O type |
Details |
|---|---|---|
|
AI |
Analog Input |
|
|
AO |
Analog Output |
|
|
DI |
Digital Input |
|
|
DO |
Digital Output |
|
|
STR |
String |
Reference syntax
The general syntax for references is as follows, but there are variations between analog, digital and string point types:
Telem_Server_<ScopeName>%<OutstationFullName>;<PointType>;<PointAddress>;<DataType>;[<PointName>]
When the optional <PointName> parameter is not specified, a default name is automatically assigned to the point. The name is in the format "<PointType>_<PointAddress>."
If you specify the PointName, enclose the name in brackets.
To create the point in a different group, add the group name to the PointName with a "." separator, as follows:
Telem_Server_<ScopeName>%<OutstationFullName>;<PointType>;<PointAddress>;<DataType>;[<GroupName>.<PointName>]