5
1.0 Introduction and General Notes
1.1 Introduction
The NOxCAN kit is a ceramic sensor-based NOx, O
2
, and pressure (optional) measurement
system that communicates and is configured via the CANopen protocol. Its primary application
is for the analysis of combustion systems and their after-treatment.
1.2 General
Notes
1.
All numbers are decimal unless preceded by the “0x” suffix which denotes a hexadecimal
value: e.g. 0x0F = 15.
2.
1 byte contains 8 bits.
3.
One “unsigned character” contains 1 byte (unsigned 8) and has a range of
0x00 – 0xFF (0 – 255).
4.
One “string” contains 1 byte (unsigned 8) and has a range of 0x00 – 0xFF (0-255). The
number represents an ASCII character.
5.
One “unsigned integer” contains 2 bytes (unsigned 16) and has a range of
0x0000 – 0xFFFF (0 – 65535).
6.
One “unsigned long” contains 4 bytes (unsigned 32) and has a range of
0x00000000 – 0xFFFFFFFF (0 – 4294967295).
7.
One “single float” contains 4 bytes (single float) that represent a decimal number using the
IEEE-754 standard.
8.
A “lo” byte and “high” byte can be combined as follows to form a 2 byte unsigned integer:
e.g. lo byte = 0x10 (16), hi byte = 0x1F (31), 2 byte integer = 0x1F10 = 31*256+16 = 7952
9.
“lo” byte can also be referred to as the least significant byte (LSB).
10.
If a subindex value for an Object Dictionary (OD) is unspecified, it is assumed to be 0x00.
11.
Data value boxes that are shown as blank are reserved; do not use these locations.
12.
All messages on the CAN bus must have a unique identifier which is referred to as “CANid”
in this manual but can also be referred to as “COB ID, communication object identifier”.