Appendix a, Can message protocol – AEM 30-2340 4-Channel Wideband UEGO AFR Controller User Manual
Page 19
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Page 19 10-2340 Rev 05 121012
Lambda values are scaled up by 10,000 to retain decimal points. For example, if a
value of 9,876 is received as a lambda value from a 4 CH UEGO controller, the actual
lambda value is 0.9876. Use the following equation to derive the actual lambda value:
Actual Lambda value = Lambda from a message / 10,000
The back pressure value is scaled up by 100. Use the following equation to derive the
actual back pressure value.
Actual back pressure value (PSIg) = pressure from a message / 100
APPENDIX A
CAN MESSAGE PROTOCOL
CAN 2.0b, 29 bit, 500 kBit/sec
8 data bytes/message
All multi-byte data packed big endian unless specified (most significant byte transmitted first)
All bits numbered with the LSB = bit0, MSB = bit7
Message ID:
0x0000001F
Source:
AEM 4 Channel UEGO set on MODE 1
Rate:
10ms continuous
Byte
Label
Data Type
Scaling
Offset
Range
0
Lambda 1
16 bit unsigned
.0001 Lambda/bit
0
0 to 6.5535 Lambda
1
2
Lambda 2
16 bit unsigned
.0001 Lambda/bit
0
0 to 6.5535 Lambda
3
4
Lambda 3
16 bit unsigned
.0001 Lambda/bit
0
0 to 6.5535 Lambda
5
6
Lambda 4
16 bit unsigned
.0001 Lambda/bit
0
0 to 6.5535 Lambda
7
Message ID:
0x00000020
Source:
AEM 4 Channel UEGO set on MODE 2
Rate:
10ms continuous
Byte
Label
Data Type
Scaling
Offset
Range
0
Lambda 5
16 bit unsigned
.0001 Lambda/bit
0
0 to 6.5535 Lambda
1
2
Lambda 6
16 bit unsigned
.0001 Lambda/bit
0
0 to 6.5535 Lambda
3
4
Lambda 7
16 bit unsigned
.0001 Lambda/bit
0
0 to 6.5535 Lambda
5
6
Lambda 8
16 bit unsigned
.0001 Lambda/bit
0
0 to 6.5535 Lambda
7
Message ID:
0x00000021