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2020/09
Signal types – Pin assignment RS485
12.4.6 Process input data
The BL××-1RS485/422-module sends the data, received by the device, into a 128-byte receive-buf-
fer. The module then transmits the data segmented via the module bus and the gateway to the SPS.
The transmission is realized in a 8-byte format which is structured as follows:
1 status byte is required to ensure trouble-free transmission of the data.
1 byte contains the diagnostics data.
6 bytes are used to contain the user data.
n = offset of input data; depending on extension of station and the corresponding fieldbus.
Signal designation
RxD Receive Data Receive data
TxD Transmit Data Transmit data
GND Ground Signal ground
Byte Byte
DP/PN
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Status byte
n n + 7 STAT TX_CNT_ACK RX_CNT RX_BYTE_CNT
Diagnostics
n + 1 n + 6 Buf_
Ovfl
Frame_
ERR
HndSh
_ ERR
HW_
Fail
PRM_
ERR
reserved TXBuf-
NotEm
pty
Data bytes
n + 2 n + 5 RX_data byte 0
n + 3 n + 4 RX_data byte 1
n + 4 n + 3 RX_data byte 2
n + 5 n + 2 RX_data byte 3
n + 6 n + 1 RX_data byte 4
n + 7 n RX_data byte 5
Designation Value Description
STAT 0-1 1: The communication with the data terminal equipment (DTE) is not
disturbed.
0: The communication with the data terminal equipment (DTE) is dis-
turbed. A diagnostics message is sent only if the parameter ”Deactivate
diagnostics = no/0“.
The diagnostic data show the cause of the communication distur-
bance.
The user has to set back this bit in the process output data by using
STATRES.
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