For projects where features like a second Ethernet interface or an RS-485 port can be omitted, the RevPi Core offers a cost-effective alternative to the RevPi Connect, without sacrificing expansion modules. The current generation of the RevPi Core is equipped with the Raspberry Pi Compute Module 4S. Like the RevPi Connect, the RevPi Core can also be expanded with I/O and gateway modules via the top-mounted PiBridge connector.
The difference between the RevPi Core S and RevPi Core SE versions is easy to explain: Both versions are compatible with the I/O expansion modules, but only the RevPi Core S can also be expanded with RevPi Gateways.
The current RevPi Core generation is available in the following variants:
 RevPi Core S |
 RevPi Core SE |
|
|---|---|---|
| Used Raspberry Pi Compute Module | ||
| Used Raspberry Pi Compute Module | Compute Module 4S | Compute Module 4S |
| Processor | ||
| Processor | Broadcom BCM2711 | quad-core Cortex-A72 | 1.5 GHz | Broadcom BCM2711 | quad-core Cortex-A72 | 1.5 GHz |
| RAM | ||
| RAM | 1 GB LPDDR4 | 1 GB LPDDR4 |
| Memory (eMMC) | ||
| Memory (eMMC) | up to 32 GB | up to 32 GB |
| WLAN | ||
| WLAN | No | No |
| HDMI | ||
| HDMI | 1 x Micro HDMI socket 2.0a (4K) | 1 x Micro HDMI socket 2.0a (4K) |
| Ethernet | ||
| Ethernet | 1 x RJ45 10/100 MBit/s | 1 x RJ45 10/100 MBit/s |
| USB | ||
| USB | 2 x USB 2.0 | 2 x USB 2.0 |
| Micro-USB | ||
| Micro-USB i | 1 | 1 |
| PiBridge (for RevPi expansion modules) |
||
| PiBridge i | 2 | 2 |
| Gateway compatibility | ||
| Gateway compatibility i | Yes | No |
| Optical indicator | ||
| Optical indicator | 3 bi-color LED, two of them freely programmable | 3 bi-color LED, two of them freely programmable |
| RTC Puffer | ||
| RTC Puffer | Double-layer capacitor | Double-layer capacitor |
| Datasheet | ||
| Datasheet | Download | Download |
Full power
The power supply circuit is one of the most important parts of the RevPi Core. In order to get as small heat from power dissipation as possible we are using state-of- the-art high-efficiency DC-DC-converter (efficiency over all is greater than 80 %). These converters use 24 VDC input (which is the usual case in industrial applications) to produce all supply voltages needed for the Core.
But our Core module does not only run on the standardized supply range of 20.4 V to 28.8 V but also runs on as little as 10.2 V input voltage*. That means you can even use car batteries or solar panels as power supply. At 24 V input any power loss of up to 10 ms will not influence operation of RevPi Core (drawing full current from both USB ports) and even up to 25 ms without USB load. Input voltage and functional earth is connected to RevPi Core using heavy duty connectors at the bottom side.
A sophisticated protection circuit guarantees continuous operation even under massive electrical or electro-magnetic interference on the input power lines (provided that functional earth is connected properly). Lightning strikes and nearby welding machines have been simulated in our test laboratories but could not impress our RevPi Core modules.
In addition, the Revolution Pi has a Real Time Clock with 24 h buffering, which ensures that the device always knows what time it is, even in the event of a power failure.
* RevPi Core can only drive 2 x 500 mA USB 5 V supply using input voltages greater than 11 V. EN 61131 demands a minimum of 10 ms tolerance against power failure which can only be guaranteed with input voltages form 20.4 V to 28.8 V. At 12 V input voltage this time decreases drastically, especially when driving loads by USB ports.
Interfaces
Like Raspberry Pi, RevPi Core is equipped with common interfaces.
Connect RevPi Core to a LAN by using the RJ45 Ethernet connector.
The RevPi Core is equipped with two USB-A connectors at the front side which can be used for USB 2.0 client devices. Both connectors can drive up to 500 mA at their 5 V supply pins. Therefore you may plug USB drives or surf sticks directly into these connectors without the need for an active USB hub.
You can connect an USB Host system (usually a PC) with the RevPi Core using the Micro-USB connector in the middle of the front plate. The RevPi Core will then boot in passive eMMC access mode and behave like an USB client memory stick. That way you may flash the module for the first time using an image file from a PC.
One Micro-HDMI plug, e.g. for connecting a video monitor.
Highly modular
The data highway connecting all RevPi modules is called PiBridge. The modules are physically connected to each other, using a system connector on the top side. Three signal types are exchanged via this connector:
4 pins of the PiBridge are used for automatic module detection during start up phase. After this phase RevPi Core exactly knows which modules are connected and in which physical position they are.
4 pins of the PiBridge are used for rapid data exchange of small data packages using RS485 signals. This channel is also used for module configuration during start up phase. After configuration this channel is used for cyclically exchanging data between RevPi Core and all IO modules connected.
8 pins of the PiBridge are used for rapid data exchange of large amount of data using Ethernet signals. Up to now this channel is only used by our modular gateway modules which may collect up to 512 Byte data cyclically from nearly all relevant fieldbusses.
Tough
One of our main goals was to give the Raspberry Pi true industrial suitability, transforming it into a proper IPC (Industrial PC). Therefore, robust 24V industrial hardware, compliant with the EN 61131-2 standard, was integrated into the DIN rail enclosure. In combination with the I/O expansion modules, the RevPi Cores can be expanded into fully-fledged, industrial-grade small controllers.
- Power supply: 12-24 VDC -15 % / +20 %, max. 10 W
- Operating temperature: -25 °C to 55 °C
- ESD protection: 4 kV/8 kV according to EN 61131-2 and IEC 61000-6-2
- Surge / Burst tests: applied according to EN 61131-2 and IEC 61000-6-2
- EMI tests: according to EN 61131-2 and IEC 61000-6-2
- UL certified (UL-File-No. E494534)
Open Source Software
Despite the fact that Revolution Pi is an open system on which everyone can install their own apps and software, we have tried to equip Revolution Pi with software and apps that cover most applications.
The operating system used is a customized version of Raspbian, which includes a real-time patch of the kernel. This is in our view the best compromise to stay as close as possible to the original development environment of a Raspberry Pi and still get a high level of control over the priorities of the tasks managed by the scheduler. The scheduler, which controls the execution of tasks by the operating system, can be extensively configured with this modified kernel, so that delays usually caused by network and other I/O accesses are avoided. Suitable drivers for the expansion modules are of course already pre-installed.
Azure certified device
Collecting sensor data, processing it and sending the processed data to a cloud is one of the Revolution Pi’s strengths. Therefore, the RevPi Core has been certified by Microsoft Azure. The certification ensures that the integration with one of the most important cloud platforms can be done as smoothly and easily as possible.
Node-RED
The pre-installed open source software Node-RED is an excellent tool for the realisation of simple automation tasks and rapid prototyping. With our specially developed RevPi Nodes the Revolution Pi modules are seamlessly integrated into Node-RED.
Modbus capabilities
Revolution Pi comes with master and slave capability for the popular Modbus RTU and Modbus TCP network protocols. External gateways are therefore in most cases no longer necessary when using these two network protocols.
Modbus TCP works with the Ethernet interface available on the RevPi Core (i. e. via the RJ45 socket on the front panel) or any other Ethernet connection (e. g. USB WLAN adapter) that is supported by the TCP/IP protocol.
Modbus RTU requires a TTY device under Linux. Since the existing UART interface of the compute module is already reserved for the PiBridge and therefore not available, a USB to serial converter such as an RS485 converter is required (not included in scope of delivery).
The configuration is done via the browser-based, graphical configuration software PiCtory.
CODESYS
Revolution Pi can be seamlessly integrated into CODESYS thanks to our drivers, making it a truly modular and powerful microcontroller for a variety of different automation tasks. Since the CODESYS runtime natively supports many fieldbus and industrial Ethernet protocols like PROFINET, EtherCAT, EtherNet/IP, or CANopen, the RevPi can easily be used as a soft PLC in such networks. With CODESYS WebVisu, user interfaces or visualization screens can be created and displayed on any common browser on PCs, tablets, or smartphones. Therefore, no separate HMI software is required. The Revolution Pi drivers for CODESYS can be downloaded for free here: CODESYS Driver.
Hinweis: Note: Additional licensing costs apply for CODESYS.