Mobile Equipment Monitoring
Getting communication data
- Data is obtained via the OBD2 (On Board diagnostics Protocol) – which is specified in SAE J1962 standard.
- One of the most important data to obtain is data from the ECU (Engine control unit) or sometime termed as ECM (Engine control module). Sometime it is also called EEMS (Electronic engine management system)
- The OBD2 (or SAE J1962) standard provides a standard list of PIDs (parameter identification umbers) for manufacturers to provide if they want to. They can also add in proprietary PIDs. For list of PIDs, see here (https://en.wikipedia.org/wiki/OBD-II_PIDs)
The OBD2 Protocol
- OBD stands for Onboard Built-in Diagnosis. It is a diagnosis system that is built into all modern cars (after 1996) which has a computer based application that monitors stuff like speed, mileage, fuel emission data etc. Apart from this it also measures some of the important vital parameters of an Engine. This complete system is called as an ECU (Engine Control Unit).
- The OBD2 specification sets a standard hardware connector to allow extraction of data. It uses a 16 pin SAE J1962 connector. OBD2 specification requires this connector to be within 2 feet (0.61m) from the steering wheel)
- This connector PIN is unique as it allows 5 different signalling protocols
- SAE J1850 PWM
- SAE J1850 VPW
- ISO 9141-2
- ISO 14230 KWP2000
- ISO 15765 CAN – this is the famous CAN BUS – THIS IS THE MOST COMMONT SIGNAL USED TODAY
- The OBD connector is meant to be used only by the service guy to monitor the health of your Car and provide diagnosis. Apart from this it is also controls the warning lights on your Cars dashboard.
- The OBD port can found below the steering wheel of every car
- For large equipment, such as those use for mining, the protocol used is the same.
- A CAN bus is a low level communication layer used within vehicles.
- Not to be confused with OBD2, as CAN BUS is the lower layer. CAN bus is one of the 5 protocol used in OBD2 Vehicle diagnostic standard. Out of the 5, it is the most common used.
- It was released in 1986 by SAE (Society of Automotive Engineer), but only started to be used widely in the 90s
- ISO released their own (but compatible to previous) CAN standards. Now the most common used is ISO 15765-2
- The CAN Protocol is only for data transmission, it does not specify the Connector PIN (Or data link layer in the OSI 7 layer model).
- Most manufacturers provide a 9-pin D-sub male connector for it. This is not to be confused with the 16 PIN SAE J1962 connector which has CAN BUS, on 2 of its pin. The 16 pin connector is used for diagnostics data and is specified in the standard.
- The 9 pin connector is also the standard connector used for serial port communication like MODBUS.
- Caterpillar is the largest Heavy Mining Mobile Equipment Manufacturer. It dominates almost 16% of market share in 2018. The next closest is Japanese Komatsu (12%)
- Since caterpillar is a US company, it uses OBD-2 for all of it’s vehicles (from small to mining equipments)
- Caterpillar has it’s own diagnostic software called CAT ET (Caterpillar Electronic Technician)
- Latest version is: Caterpillar ET 2019C
- The ET software connect to a Caterpillar machine by means of an Adapter. The latest adapter is called Caterpillar Adapter 3. The connecting point is a J1939 connector (See picture below).
- The versions are as follows:
- CAT Adapter 2 (Caterpillar 275-5120/5121)
- CAT Adapter 3 (Caterpiller 317-7484/7485) – Latest version
- A Caterpillar adapter will normally have the following cables
- J1939/J1708 Cable (Connects the adapter to the truck)
- USB Cable (Connects the adapter to a PC)
- This side (above) connects to the truck. This can be done with 3 types of connector (below) cables
- J1939 Female – For CAN Bus
- J1939 Type1 – For CAN bus
- J4 Pins (PN 457-6114) for Caterpillar Excavator
- This side (above) allows provides a female connector cable which connects to the PC via USB (PN 370-4617)