This is the second part of USBCAN analyzer receiving no data . 3. Baund rate of the bus If the baud rate between different CAN devices is inconsistent, it is definitely not possible to communicate. If you do not understand the baud rate of your CAN device, the baud rate auto-recognition function of the USBCAN analyzer is helpful. Therefore, you must pay attention to whether this analyzer has CAN baud rate recognition function when purchasing USBCAN analyzer. If not available, it is very difficult to detect the unknown device baud rate. The USBCAN analyzer has two baud rate recognition functions: the first is the silent mode, in which active CAN data is required on the CAN bus so that the USBCAN analyzer can recognize the baud rate. It is usually recommend for measuring the baud rate of the car bus. The second is the enhanced mode. In this mode, the USBCAN analyzer will actively send CAN data to devices, which is more suitable for detecting CAN bus devices that do not actively send data. The disadvantage of enhanced mode is that it may causes a bus error in the unknown baud rate devices.
Of course, the baud rate of many devices has a fixed reference value. We have listed the following devices: gasoline vehicles: 500K，250K，125K，100K diesel vehicles: 250k servo motor controller: 250 k, 250 k EPEC controller：250K，500K Fire host communication: 5K, 10K, 13.3K 4. USBCAN Analyzer error If the data is still not available after checking all the external factors, you can perform a self-test on the USBCAN analyzer. You can short the two L and two H of the USBCAN analyzer according to the picture below, turn on the right terminating resistors and then configure the two channels with the same baud rate, select the normal mode, click send. If another channel can receive a frame immediately, there is no problem with the USBCAN analyzer. If you find that the USBCAN analyzer is not communicating properly during self-test, please contact us for after-sales technical support.
5. Target CAN bus device problem You need to initially measure whether their CAN devices are in good condition, and whether they can normally send CAN signals to communicate with other devices. First, measure the voltage value of the CAN device, using a multimeter to measure the voltage value of the target CAN device CANH and CANL to ground. If it is not within the range of 2.5V ± 1V, the CAN transceiver or hardware line is faulty. If the target CAN device is a development board, you need to check the internal program of the development board, because the baud rate of the development board is likely to be biased due to program problems. At this point, the automatically identify the baud rate function of USBCAN analyzer can be used to identification(full range). If you are connected to a vehicle, please make sure the pin you are accessing is a high speed CAN bus pin. Not all 6-pin and 14-pin of the OBD interface in vehicles are high-speed CAN pins. If the vehicle has a gateway, please connect the CAN line to the ECU to read the data directly. Here’s all the common ways to check no data receiving and hope it will help you during using USBCAN analyzer.
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