32
Operating Instructions
Report Slave ID
The report slave ID function returns the following standard packet:
Name
Length
Value
Description
Address
1 byte
Varies
Modbus Address of the meter
Function Code
1 byte
0x11
Report Slave ID function code
Byte Count
1 byte
Varies
Number of bytes in Slave ID, Run
Indicator Status, and Additional Data
Slave ID
1 byte
0x02
WattNode meter Slave ID byte
Run Indicator Status
1 byte
0xFF = ON
Always returns 0xFF
Additional Data
Variable,
typically 64
ASCII string,
null terminated
Example: “Continental Control
Systems LLC, WattNode MODBUS,
WNC-3Y-208-MB“
CRC
2 bytes
Varies
Packet checksum
Table 7: Report Slave ID Response
The standard values for the Additional Data field follow:
WattNode Model
Response String
WNC-3Y-208-MB
Continental Control Systems LLC, WattNode MODBUS, WNC-3Y-208-MB
WNC-3Y-400-MB
Continental Control Systems LLC, WattNode MODBUS, WNC-3Y-400-MB
WNC-3Y-480-MB
Continental Control Systems LLC, WattNode MODBUS, WNC-3Y-480-MB
WNC-3Y-600-MB
Continental Control Systems LLC, WattNode MODBUS, WNC-3Y-600-MB
WNC-3D-240-MB
Continental Control Systems LLC, WattNode MODBUS, WNC-3D-240-MB
WNC-3D-400-MB Continental Control Systems LLC, WattNode MODBUS, WNC-3D-400-MB
WNC-3D-480-MB Continental Control Systems LLC, WattNode MODBUS, WNC-3D-480-MB
Table 8: Slave ID Additional Data Field Values
Modbus Register Lists
This section lists the Modbus registers. The following sections provide detailed information about
each register. The registers are grouped as follows:
●
Basic Registers
: Floating Point
●
Basic Registers
: Integer
●
Advanced Registers
: Floating Point
●
Advanced Registers
: Integer
●
Configuration Registers
: Integer
●
Customer Diagnostic Registers
: Integer
●
Option Information Registers
: Integer
●
Custom Register Map
Modbus Register Addressing
There are a few points about Modbus register addressing that can cause confusion.
●
In the Modbus specification, register numbers are documented as “one based”, but transmit-
ted as “zero based”. For example, we document that
EnergySum
appears at address
1001
.
If you are using any Modbus software or Modbus aware device, you should use “1001” as the
register address. However, if you are writing your own low-level Modbus driver or firmware,
you will need to subtract one from the register number when creating the Modbus frame (or
