RoadTest: PicoLog Data Logger + Raspberry Pi 4 (included)
Author: weiwei2
Creation date:
Evaluation Type: Test Equipment
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?: Fluke 1732 energy logger
What were the biggest problems encountered?: shipment delay due to covid19 but not too bad
Detailed Review:
I have written in my previous blog of my few hours testing with Fluke 1732
The Raspberry Pi
A Raspi 4 2GB comes with the roadtest unit. It is not the first time i use a raspi 4 but this time i intend to do some deeper thought onto it.
How much memory do i need?
For one, Pi 4 is available in 1GB, 2GB and 4GB version. From discussion i read elsewhere online, for most cases, 1GB is suitable only if
we don't use display, due to the fact that the Pi 4 doesn't have video memory. 2GB and 4GB are suitable with display. So, i would think
the pi 4 that comes along is suitable for running and displaying the PicoLog software on a monitor.
Heatsink ?
I have used older raspi with and without heatsink, also with and without fan. So far, all options have worked. How about Pi 4? Again, i refer to discussion online
that it can run totally fine without heatsink or fan, although with cooling its performance is better. I have decided to roadtest without extra heatsink or fan.
However, we can update the firmware to optimize its performance without heatsink, by following this online article.
OS
There are a few choices of Linux distribution suitable for Pi 4. I try to find some documents or guide on PicoLog product page to see which one is recommended. There is none specifically mentioned so
i choose to install Raspbian
PicoLog CM3
Product Page Organization
A good starting point is start with the product landing page at PicoLog product page
It is well organized and easy for user to browse for information. There is document page that lists all the relevant documents on https://www.picotech.com/data-logger/cm3/picolog-cm3-manuals
i always like this sequence personally :
1) product landing page and look at quick specification or datasheet
2) read through quick start guide (if there is any)
3) read through user guide
4) programming guide (not all test equipment has such document, some of them integrate into user manual.
5) refer to application notes where necessary. PicoLog CM3 current data logger document page has 1-4. It also has a FAQ document
i start with the USB Data Logger Quick Start Guide https://www.picotech.com/download/manuals/picolog-data-logger-quick-start-guide.pdf , in which it is a general guide for all USB data logger and not just the PicoLog CM3
Data Logger. The most important information is that we need to install the PicoLog software prior to plugging in the data logger itself. Currently PicoLog 6 is used and the software is free of charge. Prior to road testing PicoLog CM3, i have already has PicoLog 6 installed and do have some prior knowledge with it. The software can also be used with other product like PicoScope.
I then look at the PicoLog CM3 current data logger user's guide. For OS, it can runs on Windows 7, Windows 8, Windows 10 32-bit and 64-bit versions. Software is also available for Linux and macOS 64-bit operating system
Although i do have PicoLog 6, mine is installed on windows 10. So i am trying to look for information about Linux support. It doesn't talk too much regarding the Linux version so i presume i can use any Linux on my Pi 4.
PicoLog CM3 current data logger programmer's guide - i notice that only windows is mentioned to be supported OS. In essence, the SDK is provided as a windows DLL.
PicoLog Frequently Asked Questions - I find this document contains lots of useful information especially on some precaution and error that we might face.
Installation and running on Linux
I install raspbian on Pi 4 and setup PicoLog 6
Testing
Originally, one of the my test is suppose to be on solar panel output. however i realize that the provided current probe TA138 is of AC current type whereas the solar panel output is DC. Hence i change my testing onto a process controller for a fermentation machine
The clamp size is just nice for the machine wires
The current clamp is rated 200A and is AC type. each current clamp has its serial number. however, tracing which wire is which channel is still the traditional way of human eye
identification. The clamp is light enough that i can even hang it on the smaller control signal of the PLC. It is just too bad the AC type is not suitable for measuring DC current
The device can be powered up with USB and accessible via USB or ethernet
upon starting, to my amazement, one of the channel is showing 1.44kA. Upon further checking i notice that it is because the GND of the probe is not pushed deep enough.
Figure Insufficient depth (exaggerated here) will cause wrong measurement
after correcting, i can get the correct reading as below
i like the the intuitive GUI where we can label each of the 3 phase wire with colour on the PicoLog
for the recording and logging, after setting the logging to endafter 5 minutes, i notice that it is not mentioned the remaining time on the screen, and seems no easy way to find out the settings.
Comparison to similar products
I have a short usage of Fluke 1732 energy logger, comparatively, the 1732 has more features
- capability to tap power from the the current clamp to power up itself.
while the cm3 doesn't have such feature, it is much lighter and can be hanged to the measurement place and powered with a typical powerbank. After power up with powerbank, the device can continue to be accessed via its ethernet port. diagram below shows the settings
CM3 can also be powered over PoE. However, i do not test this option.
-the 1732 is a energy meter and as its name suggest, comes with more advanced maths function to measure energy usage. it also comes with IoT capability (need extra purchase)
CM3 has software SDK and to user is able to do programming to achieve the same result, of course, with more effort.
Programming
The software SDK is tested to be with the CM3
with the Raspberry Pi, one cannot help to think what we can do with it. One way is to use it as a IoT edge device, and the current measurement becomes the measurand
Summary
One may ask, is it suitable to use Pi 4 for industrial application? My opinion is YES. In fact, i have manufacturing client who do use Raspberry Pi system done by us for data logging purpose, for application like bar code scanning and sensor data acquisition and simple IO control. The fact that Pi 4 can work well without fan is a plus point as fan is still subjected to some wear and tear possibility. However, using Pi for this current data logging is first time for me.
the listed typical applications of CM3 is as below
i would think CM3 fits the applications, albeit lacking some advanced measurement math function
Pro
Good logging software that comes with no extra cost. Comparatively, other vendors tend to charge for their data logging software capability.
supports USB and ethernet. It also supports POE
Cons
only windows DLL is provided. It will be great if driver for other OS is provided. Nowadays, .NET core supports cross platform, provided the library is provided as NUGET components that we can install via NUGET package manager in visual studio.
doesn't have built in math function that perform more advanced measurement (like energy measurement) and is left to the user to do further analysis
