36 Process Image
WAGO-I/O-SYSTEM 750 XTR
750-652/040-000 Serial Interface RS-232/RS-485 XTR
Manual
Version 1.3.0
Table 25: Status Byte S1
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
EOV
EFR
EPR
CTS
BUF_E
IL5
IL4
IL3
IL3
Input length
(number of characters received that are available in the input data, bit 3)
IL4
Input length
(number of characters received that are available in the input data, bit 4)
IL5
Input length
(number of characters received that are available in the input data, bit 5)
BUF_E
Buffer empty (message: transmit inactive)
CTS
1)
This value is always 0.
EPR
Error parity (message: error during the parity check)
EFR
Error framing (message: data frame is defective)
EOV
Error overrun (message: a character was lost during receipt)
1)
Only applies to flow control “RTS with lead/follow-on time”.
Bit 4 state:
Bit 4 is 0: Receiving level “Space” (+3 V … +15 V) at the CTS input
Bit 4 is 1: Receiving level “Mark” −3 V … −15 V) at the CTS input
For evaluation of the bits of the status byte that signal errors, see chapter
“Diagnostics”.
4.2
Data Exchange Mode
The data to be sent and received will be stored in up to 47 input and output bytes
(D0 ... D46). Data flow is controlled with control and status bytes C0 and S0.
Table 26: Process Data in Data Exchange Mode
Process
Image
Length
Input Data
Output Data
8 bytes S0 Status byte 0
C0 Control byte 0
D0 Data byte 0
D0 Data byte 0
D1 Data byte 1
D1 Data byte 1
D2 Data byte 2
D2 Data byte 2
…
…
D6 Data byte 6
D6 Data byte 6
24 bytes D7 Data byte 7
D7 Data byte 7
…
…
D22 Data byte 22
D22 Data byte 22
48 bytes D23 Data byte 23
D23 Data byte 23
…
…
D46 Data byte 46
D46 Data byte 46
