For a new project I like to use the Revolution PI. Only I need some advice on what hardware I need.
Situation:
8 Ethernet Switch Point all connectect over fiber. Distance between switches between 200 ~ 400 meters. Same switches provide PC network IP Cam and VOIP.
On every location I need to monitor / switch 8 I/O.
What hardware do I need on every location?
Hardware advice
Hi,
what exactly do you mean by monitoring/switching IO? How fast, which kind of protocol to send the Io status to/from where?
If you are running your own C or Python software on the RevPi Core to monitor/switch the IOs and build in a Rest or Post Interface and /or connect to a cloud using MQTT etc. the RevPi Core 1 migth be fast enough to do this work. If you are going to use Node.red and/or any kind of Webserver Webpages as GUI promoted over the ethernet to switch an dmonitor the IOs then I would say you would better take the RevPi Core 3 to get this running with a nice performance. So Each of the nodes should have 1 RevPi Core and 1 RevPi DIO and of course a 24 V Powersupply and may be also some kind of relays if you want to swicth other items than 24 V actuators. Inputs also must be 24 V (PNP switching) Sensors.
what exactly do you mean by monitoring/switching IO? How fast, which kind of protocol to send the Io status to/from where?
If you are running your own C or Python software on the RevPi Core to monitor/switch the IOs and build in a Rest or Post Interface and /or connect to a cloud using MQTT etc. the RevPi Core 1 migth be fast enough to do this work. If you are going to use Node.red and/or any kind of Webserver Webpages as GUI promoted over the ethernet to switch an dmonitor the IOs then I would say you would better take the RevPi Core 3 to get this running with a nice performance. So Each of the nodes should have 1 RevPi Core and 1 RevPi DIO and of course a 24 V Powersupply and may be also some kind of relays if you want to swicth other items than 24 V actuators. Inputs also must be 24 V (PNP switching) Sensors.
Unser RevPi Motto: Don't just claim it - make it!
Hi Volker,
Thank you for the quick reply. A respone of 100ms is fast enough.
I understand that I need to use a relay or other activator for switching high current.
It will be used for a 7 1/4'" model train track. For switching lights and track changes.
What I like to do is replace the old switch panel with manual switches for a big 37 inch touch screen. Where everything is controlled on. At this moment we are using a Mitsubishi PLC and a lot off multi cable to hardwire everything.
To create more freedom we want to implement the fiber Ethernet cable around the track and place central point with a RevPI and some hardware to control on local side.
Thank you for the quick reply. A respone of 100ms is fast enough.
I understand that I need to use a relay or other activator for switching high current.
It will be used for a 7 1/4'" model train track. For switching lights and track changes.
What I like to do is replace the old switch panel with manual switches for a big 37 inch touch screen. Where everything is controlled on. At this moment we are using a Mitsubishi PLC and a lot off multi cable to hardwire everything.
To create more freedom we want to implement the fiber Ethernet cable around the track and place central point with a RevPI and some hardware to control on local side.
Wow, that sounds like a lot of fun!
You MUST show us pictures of what you have today
Now to the technical solution I have in mind:
You do not really want to automatic control the system, right? You only want to have a modern kind of manual control over a GUI.
So The easiest way is to use one RevPi Core 3 as a central GUI control (using a HDMI/USB Touch Panel) which might work with a Python programmed GUI or may also one of our SCADA software (in this case may be X-Vision from cricket automation) if you are not experienced in sw programming a GUI. This RevPi Core 3 is running a Modbus TCP master which is cyclically exchanging data with multiple slaves over Ethernet. Each slave would be a RevPi Core 1 combined with one DIO (that would be 14 inputs and 14 outputs per slave). If your sensors and actors are running on 24 V you would not mandatory need relays as our DIO modules do drive up to 500 mA per channel which is 12 W. This does easily drive bright shining LED signals etc. and may also drive magnets for track switches etc. Each of these slaves need a little program which does exchange the Modbus registers data with the IO data in what we call the central process image. such a program is very easy to be written. It is more or less like this:
Read data out of process image at the offset where the modbus register is placed and write this data into the process image at the offset where the output data is placed. Then read data out of process image at the offset where the Input data is placed and write this data into the process image at the offset where the modbus register is placed. Repeat this every 50 ms. This is about 20 lines of code in C or Python.
Good luck and I'm looking forward to see this in the Forum "My project" here on Revpi Forums.
B.T.W.: Where is your project located? Are you running steam engines too?
You MUST show us pictures of what you have today
Now to the technical solution I have in mind:
You do not really want to automatic control the system, right? You only want to have a modern kind of manual control over a GUI.
So The easiest way is to use one RevPi Core 3 as a central GUI control (using a HDMI/USB Touch Panel) which might work with a Python programmed GUI or may also one of our SCADA software (in this case may be X-Vision from cricket automation) if you are not experienced in sw programming a GUI. This RevPi Core 3 is running a Modbus TCP master which is cyclically exchanging data with multiple slaves over Ethernet. Each slave would be a RevPi Core 1 combined with one DIO (that would be 14 inputs and 14 outputs per slave). If your sensors and actors are running on 24 V you would not mandatory need relays as our DIO modules do drive up to 500 mA per channel which is 12 W. This does easily drive bright shining LED signals etc. and may also drive magnets for track switches etc. Each of these slaves need a little program which does exchange the Modbus registers data with the IO data in what we call the central process image. such a program is very easy to be written. It is more or less like this:
Read data out of process image at the offset where the modbus register is placed and write this data into the process image at the offset where the output data is placed. Then read data out of process image at the offset where the Input data is placed and write this data into the process image at the offset where the modbus register is placed. Repeat this every 50 ms. This is about 20 lines of code in C or Python.
Good luck and I'm looking forward to see this in the Forum "My project" here on Revpi Forums.
B.T.W.: Where is your project located? Are you running steam engines too?
Unser RevPi Motto: Don't just claim it - make it!
Hi Volker,
Thank you for the information and your ideas for this project.
We are looking around for the best solution and every help is very welcome.
I have a quite bit experience with python and GUI programming. The GUI part is most of the time my problem.
The project is located in The Netherlands
(official webpage) http://www.landgoednienoord.nl/treinen/nienoord-spoor/
(un official volunteer pages) http://www.nienoordspoorwegen.nl/stats/ Running on Raspberry PI one with long range RFID tags
For a large photo album http://www.nienoordspoorwegen.nl/fotoboek
And yes I am a steam train driver
Thank you for the information and your ideas for this project.
We are looking around for the best solution and every help is very welcome.
I have a quite bit experience with python and GUI programming. The GUI part is most of the time my problem.
The project is located in The Netherlands
(official webpage) http://www.landgoednienoord.nl/treinen/nienoord-spoor/
(un official volunteer pages) http://www.nienoordspoorwegen.nl/stats/ Running on Raspberry PI one with long range RFID tags
For a large photo album http://www.nienoordspoorwegen.nl/fotoboek
And yes I am a steam train driver
