Wildeye Support
Wildeye Support
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MODBUS Input Limitations

MODBUS Input Limitations

Wildeye has a limitation of configuring a maximum of 13 x 8-byte (64-bit) MODBUS inputs.

However, if the desired data are consecutive registers in the slave device, a recommendation is to use one wildeye modbus input to retrieve consecutive registers (max 8 bytes).

Then a "Calculated Input" to retrieve the desired bits/bytes and reconstruct the original individual registers data.

For example,

Function Code 3 (Read Holding Registers)

  • Mobus Address 1 = 2 bytes indicating Apartment A's water usage

  • Mobus Address 2 = 2 bytes indicating Apartment B's water usage

  • Instead of creating two inputs, we create one input named AptA_B with following configuration: 

    • Modbus Address = 1 and retrieve 32-bit data (4 bytes).

    • Now we need to split the 32-bit data into two 16-bit data, one which gives value for Apartment A and other for Apartment B water usage.

    • In Calculated input for Apartment A, we use the following VB formula:  Return System.BitConverter.ToInt16(System.BitConverter.GetBytes(System.Convert.ToUInt32(Inputs.AptA_B)), 2)

    • In Calculated input for Apartment B, we use the following VB formula: Return System.BitConverter.ToInt16(System.BitConverter.GetBytes(System.Convert.ToUInt32(Inputs.AptA_B)), 0)

    • The above calculation is considering the data sent by sensor is in big endian.

  • If we need to split 64-bit data and do complicated calculations, following formulas are used retrieve 2 bytes of data each:

    • Dim Data1 = (System.BitConverter.ToUInt16(System.BitConverter.GetBytes(System.Convert.ToUInt64(Inputs.AptA_B)), 6))
      Dim Data2 = (System.BitConverter.ToUInt16(System.BitConverter.GetBytes(System.Convert.ToUInt64(Inputs.AptA_B)), 4))
      Dim Data3 = (System.BitConverter.ToUInt16(System.BitConverter.GetBytes(System.Convert.ToUInt64(Inputs.AptA_B)), 2))
      Dim Data4 = (System.BitConverter.ToUInt16(System.BitConverter.GetBytes(System.Convert.ToUInt64(Inputs.AptA_B)), 0))
      Return (Data1 +  * (10^Data2) + Data3 * 65536) + Data4

  • Please refer VB documentation for the description of the System related APIs