Data exchange, function

Status byte in process data mode

The status byte is transmitted from the terminal to the controller. It is used as a diagnostic byte for data transmission and thus indicates the state of the data communication with the partner terminal.

  • Data frame:
    8 data bits, 1 start bit, 1 stop bit, even parity

Faulty data is not transmitted to the controller. If the CHK, OVR or PAR bit is set, the process data is still valid. These bits merely indicate the quality of the data transmission.

MSB

REG=0

 

 

RCVT1

RCVT2

CHK

OVR

PAR

 

  • PAR: Parity error or incorrect data frame
  • OVR: Buffer overflow
  • CHK: Incorrect checksum
  • RCVT2: The partner terminal is in RCV timeout
  • RCVT1: The terminal receives no data from the partner. The inputs of the controller were set to zero by the terminal.

 

For application without a status byte, the transmission link can be monitored from the other side of the link through a bit set by the controller. The transmission of the KL6051 is monitored by a watchdog. This makes fieldbus failures or transmission failures between the KL6051 devices easy to detect.