User Manual

4/18/2011 Page 5 of 8
SignalFire Telemetry - Rev 5.0
it is converted to the HEX modbus command.
Modbus Write Register Instructions
The Modbus Master device will issue a standard Modbus protocol command in RTU
format to the Gateway. The register write command will be automatically forwarded
over the air to the remote modbus device. The commands that are currently supported are
as follows:
0x05 MODBUS_WRITE_BOOLEAN (1-bit coil)
0x06 MODBUS_WRITE_REGISTER(16-bit integer),
0x06 MODBUS_WRITE_REGISTER(32-bit integer or float),
0x10 MODBUS_WRITE_REGISTERS(16-bit integer),
0x10 MODBUS_WRITE_REGISTERS(32-bit integer or float).
*For issuing multiple writes, no more than ten(10) 32-bit registers and twenty(20) 16-bit
register can be written in one command.
For more information on issuing modbus commands and their formats, please see the
Modbus Protocol. For device specific information regarding Enron Modbus protocol,
please see Enron Modbus Protocol for CB181 FCUs or Enron (AGA7) Modbus Protocol
for 6400 (5333) FCUs.