Hi
My question is how fast is the CM3 with analog and digital IO?
What is the cycle time?
I'm working on a project where I want to build a system to control some digital IO (Open/close valves, start/stop motors and so on). In the meantime log analog data (4-20mA) from 6 industrial instruments and also log 3 digital IO.
As it is now, I use a pc-logger with 50ms sample time. Is this possible to achieve with the CM3?
How much CPU is used by your background software? IO modules and so on?
Is it much room for any own software?
Thanks!
How fast is the hardware?
No worry... this will work out fine. Your cycle time will be way under 50 ms, probably something under 20 ms. It depends on the amount of cyclical data from the IOs which on the other hand depends on the configuration of the IOs (counter/encoder or direct input, PWM or direct outputs, etc.). Therefore it is difficult to predict but as a rule of thumb you can expect a fully used system (10 IO Modules with consuming configuration) to have a cycle time not more than 40 ms while a small system often will have cycle times near or even under 10 ms.
The CPU usage for a full system is max. 30% to 40% so there is a lot of compute power left for your app. We have made disappointing experiences with running a browser on the system in parallel to the web-server (which is always running). Most browsers are consuming awful lot of compute power (read blogs in the internet about raspberry pi and browser and you will find many people complaining and being surprised that a browser drives their system to 100% CPU usage...).
On some of our exhibits for trade shows we are running lots of things in parallel: Our robot demo is controlling the robot and a conveyor with several digital and analog sensors (using our Kernel driver and Python) . There is a GUI running on the same machine outputting data to a HDMI monitor. A demon is observing the data and moves it to the cloud whenever certain events happen or values are changing. TeamViewer for RevPi is using the web-server's output and transfers it to any remote browser anywhere in the world. RealVNC is transmitting the HDMI output to smartphones and PCs anywhere on the world. CPU usage is on average at 40%.
The CPU usage for a full system is max. 30% to 40% so there is a lot of compute power left for your app. We have made disappointing experiences with running a browser on the system in parallel to the web-server (which is always running). Most browsers are consuming awful lot of compute power (read blogs in the internet about raspberry pi and browser and you will find many people complaining and being surprised that a browser drives their system to 100% CPU usage...).
On some of our exhibits for trade shows we are running lots of things in parallel: Our robot demo is controlling the robot and a conveyor with several digital and analog sensors (using our Kernel driver and Python) . There is a GUI running on the same machine outputting data to a HDMI monitor. A demon is observing the data and moves it to the cloud whenever certain events happen or values are changing. TeamViewer for RevPi is using the web-server's output and transfers it to any remote browser anywhere in the world. RealVNC is transmitting the HDMI output to smartphones and PCs anywhere on the world. CPU usage is on average at 40%.
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