X20 system modules • X20 electronics module communication • X20CS2770
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X20 system User's Manual 3.10
4.18.8.7.9 Transmit buffer for IF1 and IF2
4.18.8.7.9.1 Number of CAN payload data bytes
Name:
TX01DataSize
TX02DataSize
Number of CAN payload data bytes to be transmitted If a value less than 0 is specified here, this CAN telegram
is marked as being invalid and is not transferred into the transmit buffer. This is useful in connection with transmit
error detection between the module and the CPU (see 4.18.8.7.9.4 "Taking possible errors into consideration when
Data type
Value
Meaning
USINT
-128 to 8
Amount of CAN payload data to be transmitted (Default = 0).
4.18.8.7.9.2 Identifier of the CAN telegram to be transmitted.
Name:
TX01Ident
TX02Ident
Identifier of the CAN telegram to be transmitted. The frame format and the identifier format are also defined in
this register.
Data type
Value
UDINT
See bit structure.
Bit structure:
Bit
Description
Value
Information
0
Standard frame format (SFF) with an 11-bit identifier
0
Frame format
1
Extended frame format (EFF) with an 29-bit identifier
0
Data frame
1
Frame type
1
Remote frame (RTR)
2
Reserved
-
3 - 20
0
In extended frame format (EFF) with 29 bits
21 - 31
CAN identifier for telegram to be transmitted
In standard frame format (SFF) with 11 bits
4.18.8.7.9.3 Configuration of the CAN payload data being sent
Name:
TX0[x]DataByte0 to TX0[x]DataByte7
TX0[x]DataWord0 to TX0[x]DataWord3
TX0[x]DataLong0 to TX0[x]DataLong1
CAN payload data in the transmit direction. The 8 payload data bytes for a telegram can be used as data points
with 8 individual bytes, 4 words or 2 longs as needed.
Data type
Value
Description
USINT
0 to 255
CAN payload data transmitted as bytes
UINT
0 to 65,535
CAN payload data transmitted as words
UDINT
0 to 4.294.967.295
CAN payload data transmitted as longs
4.18.8.7.9.4 Taking possible errors into consideration when transmitting
Data on the POWERLINK network or X2X Link can be lost due to transmission errors. One-time failures of cyclic
data are tolerated by the I/O systems. This is possible since all I/O data is re-transferred in the subsequent cycle.
A transfer error cannot be detected from the I/O variables; they remain frozen on the value from the last cycle.
These tolerated one-time I/O failures can lead to data loss or the delayed CAN telegram transmission. The counter
feedback is derived on the module and used to detect these cases.
Register for counter feedback:
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