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DownloadThis is the first post in a 4-part series about configuring and reading logged data using a Kvaser Memorator 2nd Generation device through kvmlib:
Developer Blog
16/09/2018
by Magnus Carlsson
Getting started with kvmlib
1 Getting started with kvmlib
This first post will give an overview on how to configure the Kvaser device using Python. Part two adds some complexity to the configuration, while part three will go deeper and show how to use kvmlib at the C API level. The last part shows how to configure the device while only having access to the removable SD card. Full program listings are available on GitHub.
1.1 Introduction
Configuration of newer Kvaser Memorator devices are normally done using the Kvaser Memomorator Config Tool, which is a Windows GUI tool. But you may also configure these devices programmatically using the Kvaser Memorator library (kvmlib) which is part of the Kvaser CANlib SDK.1
Our device of choice today is the Kvaser Memorator Pro 5xHS2 which runs firmware version 3.113. We will also be using v1.6 of the Python canlib package and v5.23 of the Kvaser CANlib SDK, the latest versions are available from www.kvaser.com/download.
1.2 Initialize the SD card
It’s not enough to just format the SD card in our operating system’s file manager, we also need to initialize the SD card using our Kvaser Memorator device. After having inserted the SD card into our Kvaser Memorator device, we connect the Kvaser Memorator device to a free USB port on our computer and run our first bit of code to format the SD card.
# 01_init_sdcard.py
from canlib import EAN
from canlib.device import Device
from canlib import kvmlib
# Find our connected Kvaser Memorator Pro 5xHS with EAN 73-30130-00778-9
ean = EAN('73-30130-00778-9')
dev = Device.find(ean=ean)
# Ask the device for some info, and print that
print(dev.probe_info())
# Open the memorator for configuration using the CANlib channel number we
# found it on. The LED will start a slow "running light" indicating that
# it is opened for configuration.
# We will use a context manager in order to make sure that we correctly
# close the internal memorator handle when we are done.
with kvmlib.openDevice(dev.channel_number()) as memo:
# Initialize the SD card with default values. The CAN LEDs will flash
# quickly during disk initialization.
print('Formatting disk...', end='')
memo.format_disk()
print(' done!')Listing 1: Initializing the SD card inside a Kvaser Memorator device.
When running this we can confirm that our device is indeed running firmware v3.11, and the device is currently connected to canlib channel 0.
CANlib Channel: 0
Card Number : 0
Device : Kvaser Memorator Pro 5xHS (channel 0)
Driver Name : kcany0a
EAN : 73-30130-00778-9
Firmware : 3.11.0.557
Serial Number : 1023
Formatting disk... done!
1.3 Create a configuration
Now we have to create a configuration which we do by writing a piece of XML code4. Let us take a simple example that just uses channel 0 and 1. We will set the bit rate on these two channels to 1 Mbit/s and log everything while in silent mode.
<?xml version="1.0" ?>
<!-- loggall.xml -->
<!DOCTYPE KVASER>
<KVASER>
<VERSION>2.0</VERSION>
<BINARY_VERSION>6.0</BINARY_VERSION>
<SETTINGS>
<MODE fifo_mode="NO" log_all="YES"/>
</SETTINGS>
<CAN_BUS>
<PARAMETERS bitrate="1000000" channel="0" silent="YES" sjw="1"
tseg1="5" tseg2="2"/>
<PARAMETERS bitrate="1000000" channel="1" silent="YES" sjw="1"
tseg1="5" tseg2="2"/>
</CAN_BUS>
<TRIGGERBLOCK/>
<SCRIPTS/>
</KVASER>Listing 2: Simple XML configuration sample.
The current version of the XML configuration is v2.0 and our device, running v3.11 of the firmware, expects binary (configuration) version 6.0.
In the next article, where we increase the complexity of the configuration, we will look into how to explicitly validate the configuration before trying to download it. For now we just make sure we enter the XML without any errors.
1.4 Download the configuration
We are now almost ready to start logging, we just need to place the configuration on the device. We will do this by reading in the XML file we just created, convert this XML configuration to a binary configuration and download the binary configuration to the device.
# 02_config_device.py
from canlib import EAN, Device
from canlib import kvamemolibxml
from canlib import kvmlib
# Look for our connected Kvaser Memorator Pro 5xHS
# Tip: It is enough to write the last 6 digits.
dev = Device.find(ean=EAN('00778-9'))
# Read in the XML configuration file
with open("logall.xml", 'r') as myfile:
config_xml = myfile.read()
# Convert the XML configuration to a binary configuration
config_lif = kvamemolibxml.kvaXmlToBuffer(config_xml)
# Open the memorator and write the binary configuration
with kvmlib.openDevice(dev.channel_number()) as memo:
memo.write_config(config_lif)Listing 3: Downloading configuration to Kvaser device.
Now we are all set to disconnect our configured device from the computer and instead connect our device to an existing CAN bus and start logging by applying power to the device’s CAN 1 bus connector.
1.5 Read logged messages
After we have logged some messages, we once again connect our Kvaser Memorator device to a free USB port on our computer and read out the result.
# 03_read_logged.py
from canlib import EAN, Device
from canlib import kvmlib
# Connect to our Kvaser Memorator Pro 5xHS with EAN 73-30130-00778-9
# and mount the log area
dev = Device.find(ean=EAN('00778-9'))
memo = kvmlib.openDevice(dev.channel_number(), mount=True)
fileCount = len(memo.log)
print('Found {} file{} on card.'.format(
fileCount,
"s" if fileCount > 1 else "")
)
# Loop through all logfiles and write their contents to stdout
for i, logfile in enumerate(memo.log):
print('Reading file {}:'.format(i))
print("Logging started at", logfile.start_time.isoformat(' '))
for event in logfile:
print(event)
# memo.log.delete_all() # Optionally, delete all logfiles
# Close the memorator
memo.close()Listing 4: Read logged messages and print to stdout.
Found 1 file on card.
Reading file 0:
Logging started at 2018-05-22 11:08:56
*t: - EAN:73-30130-00778-9 s/n:1023 FW:v3.11.557 LIO:v5.0
t: 0.236734012 DateTime: 2018-05-22 11:08:56
t: 0.236734012 Log Trigger Event (type: 0x1, trigno: 0x00, pre-trigger: 0, post-trigger: -1)
t: 4.453331987 ch:0 f: 2 id: 490 dlc: 2 d:5d d6
t: 4.453332025 ch:1 f: 2 id: 490 dlc: 2 d:5d d6
t: 4.453731112 ch:0 f: 2 id: 284 dlc: 2 d:a8 b1
t: 4.45373115 ch:1 f: 2 id: 284 dlc: 2 d:a8 b1
t: 4.454201237 ch:0 f: 2 id: 739 dlc: 2 d:7a 4b
t: 4.454201275 ch:1 f: 2 id: 739 dlc: 2 d:7a 4b
t: 4.454729362 ch:0 f: 2 id: 622 dlc: 6 d:8d b9 69 8a 98 e1
t: 4.4547294 ch:1 f: 2 id: 622 dlc: 6 d:8d b9 69 8a 98 e1
t: 4.455189487 ch:0 f: 2 id: 559 dlc: 1 d:78
t: 4.455189525 ch:1 f: 2 id: 559 dlc: 1 d:78
t: 4.455685612 ch:0 f: 2 id: 33a dlc: 1 d:0d
t: 4.45568565 ch:1 f: 2 id: 33a dlc: 1 d:0d
t: 4.456254737 ch:0 f: 2 id: 463 dlc: 6 d:14 eb d6 ae ed 46
t: 4.456254775 ch:1 f: 2 id: 463 dlc: 6 d:14 eb d6 ae ed 46
t: 4.456754862 ch:0 f: 2 id: 59b dlc: 6 d:7f a9 28 3a f2 5d
t: 4.4567549 ch:1 f: 2 id: 59b dlc: 6 d:7f a9 28 3a f2 5d
t: 4.457269987 ch:0 f: 2 id: 103 dlc: 8 d:4e 0d 1a dd 8d b2 19 ab
t: 4.457270025 ch:1 f: 2 id: 103 dlc: 8 d:4e 0d 1a dd 8d b2 19 ab
t: 10.220507812 DateTime: 2018-05-22 11:09:06That’s it for this time. We have now seen how to configure and read back logged data using kvmlib. In the next part, we will branch out and look at adding some complexity to the configuration.
Footnotes
1 For an overview of all the Kvaser SDK libraries, please read the blog post about how to Get more from your hardware with Kvaser SDK libraries.
2 The product number of Kvaser Memorator Pro 5xHS is 73-30130-00778-9
3 Firmware for Kvaser Memorator Pro 5xHS is bundled in the Kvaser Firmware Update Tool which can be downloaded here.
4 The XML configuration format is described in the document Specification of Kvaser Memorator Device configuration XML format, which is available here.
