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Revolution Pi Hardware FAQ
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Revolution Pi Hardware FAQ

Owned by Ulrich Kouatang Biakoup
Last updated: 08.Jul 2024 by Dirk Conzelmann
13 min read

Can I …?

Can I use a temperature sensor with Node-RED?

Yes, for example with a 1Wire USB bus coupler and the DS9490R from ESRA, which is listed here as tested:

https://flows.nodered.org/node/node-red-contrib-owfs

Would it be possible to connect a 3-wire PT100 to the analog inputs of a RevPi Compact?

  • The RevPi Compact does only support 2 wire PT100 RTD, which must be connected to an input, and it's 0V pendant.

  • If the sensor is only available as a 3 or 4 wire variant, you could use an external temperature transducer (converts the RTD to 0-10 V / 4-20mA)

https://revolutionpi.com/forum/viewtopic.php?t=4269

Can I put a CM4S in a Revolution Pi Compact Module?

  • No, unfortunately the CM4S it is incompatible.

Can I use the 3 unlabeled LEDs on the DIO module?

No, they are not assembled on the circuit board.

https://revolutionpi.com/forum/viewtopic.php?t=4227

Can I use PTP Time Stamps?

Yes, take a look here:

https://revolutionpi.com/forum/viewtopic.php?t=4203#p15023

Can I use absolute encoders?

Currently, the Revolution Pi's "Encoder" option primarily supports incremental encoders.

https://revolutionpi.com/forum/viewtopic.php?t=4172#p14889

How can I implement an Emergency stop on the RevPi

take a look at the following link : https://revolutionpi.com/forum/viewtopic.php?t=3851

Can I get the 14-pin connector of the DIO module?

Our connector in the color gray is a special production. The same connector in black or green is available from Phoenix Contact.

Can I operate a thermocouple on a Revolution Pi module, i.e., an AIO module?

  • No, unfortunately not.

Can I expand the RevPi's internal memory with an SSD or NVMe?

We do not currently offer memory expansion on any of our units except via USB.

→ Related to Core 1/3/3+/SE/S, Connect 3/3+/SE/S, Flat, Compact

Can I destroy modules in a hardware setup because of a short circuit?

In a hardware setup with several IO modules and a Revolution Pi Connect SE module, a short circuit occurred at power up. I should mention that at the time of the damage to the IO modules, a USB cable was attached to put the controller into bootloader mode to read the disk image, so I was thinking maybe the cable was defective. However, I tested the cable OK on other devices and it seems to be fine. How can this be?

  • The Revolution Pi Connect SE module works and is not affected by the polarity reversal because it has a galvanically isolated power supply.

  • If individual IO modules are connected with reversed polarity, this can lead to destruction.

  • Take a look at Video Tutorial #12 – Controlling the Digital IO Modules with the PiBridge. There it is explained why a short circuit can occur due to the polarity reversal of individual modules. https://revolutionpi.com/tutorials/video-tutorials/#VT12

  • It certainly couldn't be the USB cable. A USB2 port does not bring the current that would be needed, USB2 sources shut down at more than 500mA, except chargers and power packs. So, no, a IO module was incorrectly polarized.

Can I experiment with the RevPi stretch image on a standard Raspberry Pi 3b+?

No, because the image was adapted to the RevPi hardware.
In the GitHub repository are all the sources to make adjustments and, if necessary, adapt the image according to your needs.

https://revolutionpi.de/forum/viewtopic.php?f=6&t=2715#p9876

Can I operate a second RevPi Con CAN module?

No, unfortunately, it is not possible to maintain more than one RevPi Con CAN module.

https://revolutionpi.de/forum/viewtopic.php?f=4&t=2705

Can I use 868 MHz with a LoRa antenna?

More or loss – take a look at Using ISM Interface for Wireless M-Bus.
There is unfortunately no process image integration out of the box. But you are free to implement it yourself.

https://revolutionpi.de/forum/viewtopic.php?f=3&t=2749

Can the DIO module also be connected to other hardware, like the Raspberry Pi 4B?

Well, that depends on whether you are willing to invest time and effort in the implementation.

The PiBridge interface and the PiControl driver are documented here:

Can I order the necessary clamps with you? I want to panel mount the Faytech monitor.

No, unfortunately not. Please contact Faytech here:
https://www.faytech.com/product/accesso ... -brackets/

What can I do when no picture appears on the HDMI screen although the power LED is on?

Do you have a micro USB cable connected? Please remove it and restart your RevPi by disconnecting it briefly from the power supply. Then it will boot normally again.

Can’t connect to hdmi and Ethernet

Can I connect the Revolution Pi Connect with I2C bus?

 

This is a workaround and therefore cannot be supported by us.

How can boot/mount the RevPi Device

there are two solutions.
1. Solution

  • Connect the RevPi with a Micro-USB cable to a Linux computer

  • run rpiboot

  • mount the 2nd partition

  • edit the fstab

  • unmount the partition

  • disconnect from USB

  1. Solution

  • Reinstall your RevPi with a new image. You'll lose all your data on the RevPi

The DI card (also the DI part of DIO) has L (bit UV2) and LL (bit UV1) voltage detection on the X2-I terminal. Why are these bits not available for the DO part, hence the X2-O terminal?

Both UV1 & UV2, are only available on DI and DIO, as these come from the input IC (MAX31913 – datasheet S10).

RevPi IO fault detection

How to keep the relay contact OPEN when the power is off?

Unfortunately, it is not possible to keep the relay contact open when the Power is off: the RevPi connect is equipped with a relay that is normally closed by default. See here: (8) Relay contact is closed when a device power is off - Revolution Pi Forum

How to configure output relay behavior on Connect SE?

Take a look at the following link: Configure output relay behaviour on Connect SE

How can I check whether a digital output has taken over the written value?

There is a great discussion here in our forum:

Best way to implement pin writing checks

How to Power off RevPi Core 3 Safely?

The product description of the RevPi Flat states that up to three devices can be connected to the network via the Eth1 interface. How does this work?

I have a project to build my own hardware and connect it to the Revolution Pi master module like Connect + or Core. How can I proceed?

Tutorial 25 – Create your own RAP file
Circuit diagrams Search after Circuit diagrams
GitHub - RevolutionPi/IODeviceExample: This repository contains the code for a RevPi DIO module. It can be used as origin for own IO modules.

Original discussion here

https://revolutionpi.de/forum/viewtopic.php?f=18&t=3118

Is there …?

Would it be possible to operate the IO cards remotely with a cable between the RevPi base module?

Yes, you have to realize this yourself, for example with a maker set:

https://revolutionpi.com/shop/en/maker-set

The RS485 interface of the PiBridge sometimes delivers a strange signal. It is not rectangular formed, is this normal?

Yes, it is normal and if the thresholds are respected the decoding works.

https://revolutionpi.com/forum/viewtopic.php?t=3958#p14109

Is there an adapter for installing a CM4 module into a RevPi module?

Yes, however, it will not boot with the CM4 device tree. https://revolutionpi.com/forum/viewtopic.php?t=3885#p13953

Would it be possible to expand the number of USB ports on a RevPi Core with a USB HUB?

Yes, that is possible. However, please keep in mind that all connected devices share a USB root port (i.e. in total only the single USB2 bandwidth is available).

The network port is also connected to the internal USB hub.

Would it be possible to use a cable extender instead of the default RevPi Connector?

The Revolution Pi products as well as expansion modules such as IO or gateways must be connected with the default RevPi Connector Bridge we have provided for this purpose so that the runtimes are not affected. Otherwise, there may be miscommunications between the modules.

However, you can try to open 2 jumpers and connect them to one line. Depending on the application, this might work.

If this leads to errors, we cannot support this.

Is the DIO capable of driving inductive loads without causing damage, or must freewheeling diodes be used?

Yes, it is possible. For example: there are already customers who operate relays on RevPi and have no problems because the currents are not really high. On the load side, the situation is different; if necessary, snubbers or (filters) should be used to intercept the high switching currents. But it always depends on the consumer.

Are there 3D models of the enclosures of the Revolution Pi devices?

Yes, in the download area you can download 3D data in the form of STEP data: https://revolutionpi.com/tutorials/downloads/?noredirect=en_US#stepdaten

Is there a recommendation for a small UPS in DIN rail format?

Without giving a rating, there are good experiences, for example with these products

There is a discussion here

Is there a more industrial way than the USB port on the front of the Revolution Pi Core to run a Modbus master on the Core?

The Revolution Pi Connect has a separate RS485 port that you can configure as a Modbus master. With the Core variant, you only have the option of doing this via USB.

I am interested in Bluetooth Low Energy 5 with the RevPi – is there any information?

With the next generation of our RevPi's, based on the CM4, there will be variants with built-in WLAN/BT. The RF chip CYW43455 used on the CM4 supports BT 5 and BLE. It is the same as on the Raspberry Pi 3B+ and 4. You can find the corresponding datasheet here: https://www.cypress.com/file/358916/download.

Is there more information about the serial number of the Crypto Chip?

Here is the data sheet from Atmel

https://ww1.microchip.com/downloads/en/DeviceDoc/20005928A.pdf

I am abroad. Is there any information on the Con-Bridge connector, so I can get it myself?

Please contact a distributor near you. Here you can find our worldwide network of distributors:

https://www.kunbus.com/distributors-worldwide

Is there an external clock for the RTC in the Revolution Pi Core3 (+)?

Yes, an RTC is installed in the Revolution Pi Core devices. The system time is buffered for 24 hours without an external power supply. This was implemented with the use of a Super capacitor.
https://revolutionpi.com/revpi-core-part-1/?noredirect=en_US

RTC error message after prolonged non-use of the Revolution Pi

Reset RTC driver

https://revolutionpi.de/forum/viewtopic.php?t=3667

Would it be possible to connect a 3,3V to RS232 level converter somewhere on the Connect+ and have a serial port available as a console or a service port for our background service?

No, the RevPi Connect/+ has a RS485 interface which uses 5 volts. Take a look at this discussion:

https://revolutionpi.de/forum/viewtopic.php?p=9633#p9633

Are there older schematics of the Revolution Pi Connect?

Yes, they are available here:

Would it be possible to install a new image on the RevPi Flat?

Is there any information about the performance of the RevPi?

Yes, we have some Information in the links below:

The performance, such as cycle time, is highly dependent on the respective application!

Is the input on RevPi Connect + PNP or NPN?

It is correct, the input on the RevPi Connect + is PNP type.

The output on the RevPi Connect + is a relay.

Here you will find circuit diagrams:

https://revolutionpi.com/tutorials/downloads/#schaltplaene

In case you would have a NPN application, you could use an inverter, e.g. https://de.rs-online.com/web/p/interface-relaismodule/5329980?cm_mmc=DE-PLA-DS3A-_-google-_-CSS_DE_DE_Relais_Whoop-_-(DE:Whoop!)+Interface+Relaismodule-_-5329980&matchtype=&pla-318322060955&gclid=Cj0KCQiA0eOPBhCGARIsAFIwTs5mWkjR8cCSNfk1okM7xPLwRBIBFeaWUIbY6Czh6h6bFlf7szvrsRIaAh1lEALw_wcB&gclsrc=aw.ds

Is there a practical example of how to use the relay contact of the RevPi Compact?

https://revolutionpi.de/forum/viewtopic.php?f=3&t=2959#p10592

#LED A1 green + relay contact active piTest -w RevPiLED,33

Would it be possible to bypass the reverse polarity protection of individual RevPi products?

Yes, unfortunately this affects the RevPi Core series (1, 3, +) Hardware-Revison: 1.0

  • in combination with other modules, if a device is connected with reverse polarity

  • in combination with different ground potentials between HDMI and the supply at X4

Take a look at https://youtu.be/Z5ddb0diOMY?t=80

Is there a reliability data for eMMC MTBF?

Is there any way to get the ConBridge connector by myself? Are there mating connectors?

  • The item is a specially molded connector for KUNBUS.

  • There are no wire-to-board mating connectors.

Is that possible to use more than one monitor?

  • Unfortunately no, currently the CM3 based RevPi Modules just have one HDMI port.

  • Surely, it will change in the future with a RevPi based on CM4.

I have noticed that the watchdog can work separately from the RevPi OS, and my goal is to create a program to manage the watchdog. It is possible?

Others Questions…?

What is the use-case for the SYNC pin on the RevPi Connect 4?

The SYNC pin was actually intended for TSN but this is no longer an issue.

(659) pibridge sync pin use-case? - The Industrial Raspberry Pi Forum (revolutionpi.com)

What is the meaning of the RS485ErrorCnt variables?

This is where transmission errors are counted on the PiBridge backplane bus. If the transmission errors exceed a value, the PiBridge is switched off. This brings the IO modules into a safe state.

(666) RS485ErrorCnt in RevPi Core S - The Industrial Raspberry Pi Forum (revolutionpi.com)

One of the black plastic clips that secures the PLC to the DIN Rail broke. Is it possible get a replacement?

Well, there is no such part number and I can understand you, so what can we do here? You can buy this thing called Maker-Set.

https://revolutionpi.com/shop/en/maker-set

Is it possible to replace a compute module?

  • Yes, see here

https://revolutionpi.com/forum/viewtopic.php?t=4223

How can you meet the EMC with a plastic enclosure?

We generally always have plastic housings without additional shielding. Additional shielding is normally not required with proper hardware design. The immunity complies with EN 61000-6-2 Immunity standard for industrial environments.

What are the voltage ranges in which a logical high signal and logical low signal are recognized?

  • The logic is based on the Norm EN61131-2

  • Check the datasheets for more informationhttps://revolutionpi.com/tutorials/downloads/#technischedatenblaetter

Our production requires that the real-time performance of the RevPi can reach 10us, can it be achieved? If not, what is the highest real-time performance of the RevPi?

It depends on what you want to control. If you would like to control devices connected via the PiBridge you can read the performance of the PiBridge.
Look at the variable RevPiIOCycle: https://revolutionpi.com/pictory-neues-revpi-core-v1-2-jessie/?noredirect=en_US
But the value is in the MS range.
The only exception is the RevPi Compact module, which is not modular and therefore has a much higher performance: https://revolutionpi.com/tutorials/digitale-ein-und-ausgaenge-compact/

Original discussion

https://revolutionpi.de/forum/viewtopic.php?f=3&t=3057#p11037

What is the upper limit on leakage current in digital outputs in RevPi DO when operated at 12V?

  • The leakage current is max. 20µA.

What is the RJ11 pin assignment of the RevPi Flat?

What size circuit breaker would you recommend for the power supply for the RevPi?

To protect the power supply, you need to read the data sheet of the power supply you are using and see what they recommend. Our RevPi can be protected with a 2A fuse (fine-wire).

I want to write x MB/day to the eMMC, what is the lifetime using an ext4 file system?

Samsung's eMMC components are installed in the Compute Module. Samsung does not specify the number of erase/write accesses for the chip in the data sheet, nor a lifetime in operating hours. Typically, eMMC has a guaranteed lifetime of approx. 10,000-30,000 write accesses for each individual cell. Experience shows that the real achievable cycle numbers of flash memories are significantly higher – due to the wide range of controller technologies used with wear levelling etc. According to the data sheet, the Samsung eMMC has a flash transition layer with wear levelling, bad block management and ECC. How far you can get without data loss is very difficult to calculate… We do not know of any failures with it so far.

The form factor of the Revolution Pi Core / Connect devices is a bit too high for my control cabinet, are there any alternatives?

The RevPi Core 3+ and RevPi Connect+ with the associated expansion modules and gateways are designed for the typical form factor in industrial control cabinets.

For use in home sub-distribution panels, we tend to see the RevPi Compact (https://revolution.kunbus.de/revpi-compact/) or the RevPi Flat (https://revolution.kunbus.de/revpi-flat/). They have the appropriate form factor for this.

There are two different versions of the RevPi Connect Module, what are the differences?

  • The "PR100304R00 - 1.0 version" contained two power supply modules. These were combined in the "PR100304R01 - 1.1 version" into one galvanically isolated power supply unit. For this reason, the 8-pin X4 connector (at the bottom of the RevPi Connect) has been changed to a 4-pin connector. The bridge for the watchdog is still pre-assembled.

  • The RS485 interface is now galvanically isolated with version “PR100304R01 – 1.1 version”.

The power supply unit is not included in the scope of delivery, which one should I use?

We recommend the following power supply unit from our shop:

https://revolution.kunbus.de/shop/en/netzteil-meanwell-hutschiene-mdr-60-24

Of course, you can also use another 24 V power supply unit, but make sure that the 24 V is applied < 30 ms; otherwise an error may occur with other modules.

https://revolution.kunbus.de/forum/viewtopic.php?f=3&t=1655&p=6759&hilit=ramp+up#p6759

I would like to use encoders, what to consider?

Hardware options

  • DI/DIO/MIO-Module plus Revolution Pi Core or Revolution Pi Connect

  • Revolution Pi Compact Module

Configuration options

I need details about PiBridge communication and pinout for a project. Where can I find details?

Are there alternative plug connections for the PiBridge, e.g. a cable connection?

No, this is not being developed. You are welcome to develop your own alternative connector, but we will not guarantee interference-free communication via the PiBridge. Keyword: EMC, length of cable, signal quality, (There is a reason why "only" up to 5 modules can be attached on each side).

Has the RevPi Compact been certified and tested according to the EN 61000-6-3 standard, which is necessary for the B2C market?

  • Yes, according to the EMC test report. However, we only issue this report upon request.

The RevPi Connect watchdog LED is lighting green. Does this mean the Watchdog is enabled?

The hardware watchdog time on the RevPi Connect is different when switching on the system, right?

Yes, when switching on the system, there is a "startup delay time", this is between min. 60s and max. 180s.
After this time comes the actual "watchdog timeout period", which is also min. 60s and max. 180s.
So the first time (power up) the times add up, after that only the timeout period time is left.
More details can be found in the datasheet of the watchdog module MAX6370:

https://www.maximintegrated.com/en/products/power/supervisors-voltage-monitors-sequencers/MAX6370.html

We want to use the RevPi water and dust protected in an IP66 housing. Any experience with overheating when there is minimal space around the RevPi?

https://revolutionpi.de/forum/viewtopic.php?f=4&t=2585#p9695

Would like to know what the consequences would be of operating a RevPi at a higher temperature than, i.e. 55°C?

The Compute Module inside the Revolution Pi devices has different thresholds according to the ambient temperature to automatically down clock the CPU frequency.

Here is a link to the data sheet of the Compute Module 4:

Among other things, it says this

image-20240424-091710-20240503-144504.png

 

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