User guide

BB2-7030 User Guide – Rev. 1.0 Page 69
would not normally be possible, for example -99 to indicate room temperature if the BB2-7030 is
unable to read the MS/TP sensor.
20.3 Modbus Function Codes Recognized by BB2-7030
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The following function codes are used by BB2-7030 as Modbus TCP master, and are also
recognized by BB2-7030 when functioning as a slave.
1 – Read Coil 5 – Write Single Coil
2 – Read Discrete Input 6 – Write Single Holding Register
3 – Read Holding Registers 15 – Write Multiple Coils
4 – Read Input Registers 16 – Write Multiple Holding Registers