Process image

The KM6551-0000 terminal module represents itself in the process image with a maximum of 12 bytes of input data and 12 bytes of output data. These are organized as follows:

Format

Input data

Output data

Byte

SB1

CB1

Byte

SB2

CB2

Array of bytes (0...9)

DataIN

DataOUT

Key

SBn: status byte n
CBn: control byte n

DataIN: Array of 10 input bytes (0...9)
DataOUT: Array of 10 input bytes (0...9)

The meaning of the control and status bytes is explained in Control and status bytes.

In process data operation, the input data is transmitted in the DataIn array and the output data in the DataOUT array.

Use of the data arrays

  • use them, for example, to transmit the process data from analog input or output channels.
  • also use the 10 bytes in order to transmit larger amounts of data in several cycles using a self-defined protocol (e.g. 2 bytes for the header, 8 bytes for the user data).