Datasheet

Leuze electronic MA 248i 49

TNT 35/7-24V

10 Telegram

10.1 Structure of the fieldbus telegram

All operations are performed by control and status bits. Two bytes of control information

and two bytes of status information are available for this purpose. The control bits are a part

of the output module and the status bits are a part of the input bytes. The data starts with

the third byte.

If the actual data length is longer than the data length configured in the gateway, only part

of the data is transmitted; the remaining data is lost. In this case, the DL (data loss) bit is set.

The following telegram structure is used between PLC -> fieldbus gateway:

This telegram structure is used between fieldbus gateway -> PLC:

Only the data part with the corresponding frame (e.g., STX, CR & LF) is then transmitted

between the fieldbus gateway and the Leuze end device. The two control bytes are

processed by the fieldbus gateway.

The corresponding control and status bits and their meaning are specified in section 10.2

and section 10.3.

Further information on the broadcast control bytes and address bits 0 … 4 can be found in

chapter "Modular interfacing unit MA 3x (S4 switch position C)" on page 100.

76543210

ND Address 4 Address 3 Address 2 Address 1 Address 0 Broadcast Command

mode

Control byte 0

CTB SFB R-ACK Control byte 1

Data byte / parameter byte 0 Data

Data byte / parameter byte 1

…

76543210

ND BO DL BLR DEX SMA W-ACK Status byte 0

DLC7 DLC6 DLC5 DLC4 DLC3 DLC2 DLC1 DLC0 Status byte 1

Data byte / parameter byte 0

Data

Data byte / parameter byte 1

…