Product Description #

The RevPi Connect S or RevPi Connect SE is a 24 V industrial PC for IIoT and automation projects based on the Raspberry Pi Compute Module 4S. The RevPi is a base module from the Revolution Pi product family. All devices in the Revolution Pi product family are developed in accordance with EN 61131-2.

Components #

Note

RevPi Connect S and RevPi Connect SE have the same structure.

revpi-connect-s-aufbau
Position Component Application

1

X2 connector

Relay output,
Digital input

2

6 × status LED

RevPiLEDs,
Watchdog,
Relay Output

3

2 × RJ45 Ethernet

RJ45 Ethernet Interfaces,
Establishing a Network Connection

4

Micro-USB

Reinstalling Operating System Image

5

2× USB A

USB Interfaces

6

RS485 socket

RS485 Serial Interface

7

X4 connector

Connecting the Power Supply,
Watchdog

8

2 × locking clip

Mounting the Device on a DIN Rail

9

Ventilation Slots

Mounting the Device on a DIN Rail

10

PiBridge

Connecting Expansion Modules

11

ConBridge

Connecting Expansion Modules

12

Micro HDMI

Setting up Desktop Mode

Variants #

RevPi Connect S #

Item No. RAM eMMC Compatible with RevPi Gateways

100362

1 GB

8 GB

100363

1 GB

16 GB

100364

1 GB

32 GB

RevPi Connect SE #

Item No. RAM eMMC Compatible with RevPi Gateways

100368

1 GB

8 GB

100369

1 GB

16 GB

100370

1 GB

32 GB

For available variants see Revolution Pi Shop.

Compatibility #

The RevPi Connect S or RevPi Connect SE base module can be expanded by up to 6 expansion modules to form a Revolution Pi system:

Left Side Base Module Right Side

5 × RevPi I/O module or
1 × RevPi Gateway + 4 × RevPi I/O module

RevPi Connect S

1 × RevPi Con CAN + 1 × RevPi Con M-Bus

5 × RevPi I/O module

RevPi Connect SE

1 × RevPi Con CAN + 1 × RevPi Con M-Bus

RevPi Gateways #

RevPi gateways can only be connected to the far left of the system via a PiBridge plug connector. The RevPi gateways are not supported by the SE models of the Revolution Pi product family.

  • RevPi Gate PROFINET

  • RevPi Gate EtherNet/IP

  • RevPi Gate EtherCAT

  • RevPi Gate PROFIBUS

Operating System Images #

The RevPi Connect S or RevPi Connect SE is compatible with the following operating system images:

Scope of Delivery #

The scope of delivery includes

  • RevPi Connect S / RevPi Connect SE (base module)

  • X4 connector with pre-wired Watchdog wire bridge

  • X2 connector

  • 2 × blind plug for PiBridge/ConBridge

  • Supplement

Mounting and Connecting #

The RevPi was developed for use in a control cabinet. Observe the specifications for the Intended Use and all Safety Instructions.

Warning
Danger to life due to electrical shock

There is a risk of fatal electrical shock when working on devices in the switch cabinet with 230 V mains voltage.

▷ Operations in the switch cabinet may only be carried out by qualified electricians.

▷ Before carrying out any operations in the switch cabinet, switch off the power supply properly.

Caution
Damage to the device due to overheating

The ambient temperature in the switch cabinet must not exceed the maximum permissible operating temperature.

▷ Keep ventilation slots clear.

▷ Observe the installation clearances.

▷ Mount the device in the intended orientation.

▷ Do not place appliances with high input power directly next to each other.

▷ Regularly remove dust and dirt from the area around the appliance.

Carry out the mounting and connection in the following order:

  1. Mount the RevPi base module and all expansion modules on a DIN rail.

  2. Connect all expansion modules via PiBridge plug connectors.

  3. If necessary, connect the RevPi Con modules via ConBridge plug connectors.

  4. Connect all other devices such as sensors and actuators. The interfaces available to you for this can be found in the section Components.

  5. Connect a monitor and a keyboard if you want to use the RevPi in the desktop mode want to operate. This is not necessary if you have a network connection to access the RevPi.

  6. Finally, close the power supply.

Note

The RevPi Gateways are not supported by the RevPi SE models.

Access to the Device #

The RevPi is accessed in two steps:

Install all available updates as soon as the RevPi is connected to the internet. This ensures that the system is always up to date with security-relevant features.

See also:

Alternatively, access is possible without a network, see Setting up Desktop Mode.

Configuration #

The RevPi is configured in two steps:

  1. Configure the RevPi base module via the application Cockpit.

  2. Configure the Revolution Pi system, i.e. a RevPi base module with expansion modules, using the application PiCtory or, if applicable, directly in your development environment, e.g. via CODESYS.

Note

CODESYS and PiCtory cannot be used in parallel for configuration. An existing configuration via PiCtory will be overwritten by a configuration via CODESYS.

The virtual devices OPC UA Server and MQTT Client can only be used via PiCtory.

Parameterization #

The following parameters, inputs (INP) and outputs (OUT) can be configured:

RevPiStatus (INP) #

Uses bits to represent different states of the piControl driver.

Bit Function

0

piControl driver is running.

1

At least one connected I/O module has not been configured.

2

At least one I/O module has been configured but not connected.

3

An I/O module occupies more or fewer bytes in the process image than specified in the configuration.
This means that the version of the configuration file or the device description files used does not match the firmware in the I/O module.
See also: Installing Firmware Updates.

4

Without function.

5

Without function.

6

Digital input on X2 connector

RevPiIOCycle (INP) #

Displays the cycle time of the PiBridge communication between the base module and expansion modules in milliseconds (ms) as an integer value.

Core_Temperature (INP) #

Displays the CPU temperature as an integer value in degrees Celsius (°C).

Core_Frequency (INP) #

Displays the CPU frequency in MHz / 10, e.g. 2400 MHz = value 240.

RS485ErrorCnt (INP) / RS485ErrorLimit (OUT) #

RS485ErrorCnt counts the errors in the communication with the RevPi I/O modules and outputs their number as an integer value.

RS485ErrorLimit1 and RS485ErrorLimit2 serve as limit values for the error handling.

Note

The communication via the serial interface RS485 to the outside is not affected, only the internal PiBridge data traffic.

RevPiLED (OUT) #

The freely programmable LEDs can be controlled via RevPiLED, see Configuring LEDs.

Bit Component Status Information

1:0
3:2
5:4

LED A1
LED A2
LED A3

0000 0000 = off
0000 0001 = green
0000 0010 = red
0000 0011 = orange
0000 0100 = green
0000 1000 = red
0000 1100 = orange
0001 0000 = green
0010 0000 = red
0011 0000 = orange

RevPiLED, Bit 6 controls the relay output on the X2 connector.

RS485 Serial Interface #

revpi-connect-rs485-pinout

The RevPi has an RS485 interface on the X2 connector to connect serial devices such as sensors.

The socket has differential data line terminals P/N and reference terminals (internal GND and functional earth via 1 MOhm RC network).

Under Linux, the interface can be addressed via the device driver node with /dev/ttyRS485 .

How you use this connection optimally depends on your project environment. The network you are working with or the EMC load are individual factors that influence how you assign this connector.

We therefore cannot show you the best solution for your individual project, but we have compiled a list of the problems that can occur and tips on how you can solve them.

RS485 is a fully differential line and does not normally require a third GND line. However, due to the limits of the input receivers (maximum common mode voltage), there may be problems with the signal quality if no potential reference is used between the transmitter and receiver. However, connecting the internal GND to a line that is subject to EMC can lead to EMC problems within the RevPi Connect.

We therefore recommend that you use a common functional earth between all RS485 network participants. This gives you a good, common reference potential for the differential bus signal.

If this does not work either, you can connect the FE terminal of the RS485 connector to the third (GND) line of the bus.

You can also try to solve signal problems with the GND terminal.

Activating Termination Resistor

✓ The integrated 120 Ω terminating resistor of the RS485 interface is switched off after a restart.

▷ Log in to the RevPi via a terminal.

▷ Check out the Git repository of the command line tool rs485_config from GitLab with the command:

git clone https://gitlab.com/revolutionpi/rs485_config.git

▷ Build the tool with the command:

cd rs485_config; make

▷ Activate the resistor with the command:

./rs485_config <SERDEV> --set-bus-term

Replace <SERDEV> with the name of the interface, e.g. /dev/ttyRS485.

▷ Check whether the resistor has been activated and display the settings of the RS485 interface with the command:

./rs485_config <SERDEV>

❯❯ If the resistor is activated, Bus termination: Yes is output.

RJ45 Ethernet Interfaces #

The RevPi can be connected to a network via the RJ45 interface.

10/100 Ethernet connections are available on the RevPi, which are independent of each other. This allows the RevPi to be integrated into two different networks. The MAC addresses are printed on the front of the housing.

As of RevPi Trixie the interfaces can be addressed under Linux via:

  • Socket A: lan0

  • Socket B: lan1

Until RevPi Bookworm the interfaces can be addressed under Linux via:

  • Socket A: eth0

  • Socket B: eth1

USB Interfaces #

The RevPi has two USB-A interfaces. The maximum output current of both USB interfaces together (not per interface) is 1 A and is only guaranteed if the RevPi is supplied with 24 V DC -15 % / +20 %.

▷ Connect a power supply input with a typical supply voltage of 24 V DC (10.8 … 28.8 V DC) to the pin labeled 24V. If only one connection is used, up to 1 A is available. If both connections are used at the same time, the current is divided accordingly.

In case of overload, the power is cut off.

Relay Output #

The RevPi provides a relay output on the X2 connector. This relay contact can be used, for example, to interrupt the power supply to connected hardware.

  • The relay can switch a maximum of 30 V and 300 mA.

  • The relay contact is normally closed (NC) after startup.

▷ Ensure that all devices are disconnected from their power supplies.

▷ Connect the load to be switched to the OUT pins on the X2 connector.

▷ Connect the power supply.

The relay output is controlled in the process image via RevPiLED, bit 6. The LED REL indicates the status of the relay contact:

RevPiLED, Bit 6 Function LED REL

0

Relay contact closed

Green

1

Relay contact open

Off

Digital Input #

The input has an internal pull-down resistor.

The digital input can be used for UPS status monitoring.

▷ Make sure that all devices are disconnected from their power supplies.

▷ Connect the signal transmitter to the IN+ and IN- pins of the X2 connector.

▷ Connect the power supply.

Date and Time #

Different mechanisms are used for time management in the RevPi. They serve different purposes and complement each other.

Network Time Protocol (NTP)

Network Time Protocol (NTP) automatically synchronizes the system time of the RevPi with a time server.

Real-Time Clock (RTC)

The RevPi is equipped with a real-time clock. When no supply voltage is present at the RevPi, the RTC is powered by a supercapacitor.

The supercapacitor is charged during operation and typically maintains the time for up to 24 hours. The actual duration depends on the environmental conditions.

Watchdog #

The RevPi is equipped with a hardware watchdog.

A watchdog is a timer that restarts the RevPi after 60 seconds. To prevent this from happening, the watchdog must be reset regularly as long as the system is running without errors. In the event of an error, such as a crash of the application process, there is no reset and the watchdog triggers a restart of the RevPi.

Activating Watchdog #

The RevPi is supplied with an X4 connector, which is already pre-wired. The wire bridge between pin 2 and pin 3 deactivates the watchdog.

The watchdog is active without this wire bridge and the watchdog timer must be restarted cyclically by your application software so that your system is not restarted. Until you have such software, it therefore makes sense to deactivate the watchdog. Otherwise it might disturb you during your development work.

▷ Remove the wire bridge between pin 2 and pin 3 to activate the watchdog.

The LED WD indicates the status of the watchdog:

  • Green = All system components are running correctly.

  • Flashes once orange = Watchdog has detected an error and restarts the system.

Monitoring the Connected Device #

The relay output allows devices connected to the X2 connection to be monitored by the watchdog.

You can switch the relay output in the process image via RevPiLED, bit 6. You can also use this to set the relay to switch when the watchdog has reported an error, for example.

You can find an example script on the RevPi.

The file watchdog.sh can be found in the directory /etc/rc.local.

You can run the script by typing the following command in the command line:

/home/pi/connect/revpi-connect-watchdog.sh >dev/null &

This script is only an example and is not suitable for controlling watchdogs or relays. However, you can use it as a template to create your own command in an application program (e.g. logiRTS).

This is how you use the watchdog to restart the relay:

▷ Patch the FTDI EEPROM:

devnum=$(cat /sys/bus/usb/devices/1-1.5.2/devnum)sudo /home/pi/connect/patch_eeprom d:1/$devnum 0x14=0xaa 0x15=0x00

You no longer need to carry out this step if you have already used the watchdog to control the relay.

▷ Restart RevPi Connect:

sudo reboot

▷ Enter one of the following commands to switch the relay on or off when the watchdog responds:

Switch on:

sudo /home/pi/connect/enable_relay_watchdog.py

Switch off:

sudo /home/pi/connect/disable_relay_watchdog.py

You must call up the desired command again after each reboot.

If you have entered this command, it is possible that the interface /dev/ttyRS485 disappears for a short time.

Technical Data RevPi Connect S #

Item No.: 100362, 100363, 100364

Housing dimensions (H × W × D)

96 × 45 × 110.5 mm

Housing type

DIN rail housing for TH35 mounting rail according to DIN EN 60715

Housing material

Polycarbonate

Weight

Approx. 197 g / 224 g (incl. connectors)

Protection class

IP20 / NEMA Class 1

Power supply

Typ. 24 V DC (10.8 … 28.8 V DC)

Maximum power consumption

20 W (incl. 1 A total USB output current)[1]

Approved operating temperature

-25 … +55 °C

Approved storage temperature

-40 … +85 °C

Max. relative humidity (at 40 °C)

up to 93 % (non-condensing)

Interfaces

  • 2 × USB A (total current draw from both sockets max. 1 A)[2]

  • 2 × RJ45 10/100 Ethernet (using separate MAC addresses)

  • 1 × RS485 screw-type terminal

  • 1 × Micro-USB (solely for image transfer to eMMC)

  • 1 × Micro-HDMI 2.0a (4K)

  • 1 × PiBridge system bus

  • 1 × ConBridge system bus


2. 1 A USB output current (sum of both USB outputs) is only available with input voltages >11 V. The bridging time of voltage dips of at least 10 ms required by EN 61131-2 is only guaranteed with a supply voltage of 20.4 … 28.8 V. At 12 V input voltage this time decreases drastically, especially when driving loads via the USB ports.

Connectors

  • 1 × 4-pole screw-type terminal for relay contact and signal input

  • 1 × 4-pole screw-type terminal for power supply

Compute Module

Raspberry Pi Compute Module 4S

Processor

Broadcom BCM2711, quad-core Arm Cortex-A72

Clock rate

1.5 GHz

Processor cooling

Passive with heat sink

RAM

1 GB LPDDR4
NOTE: The Linux GUI should only be used on RevPi devices with at least 2 GB RAM.

Flash memory

8 GB (Item No.: 100362), 16 GB (Item No.: 100363), 32 GB (Item No.: 100364)

Number of digital inputs

1

Digital input type

24 V control voltage (e.g. for power-good signal of a UPS)

Input threshold

Approx. 3.0 V (0 → 1) resp. 2.3 V (1 → 0)

Input protection

Against overvoltage and negative voltages

Number of digital outputs

1

Output type

Relay contact (NC), approved up to 30 V switching voltage (e.g. for power supply of a router)

Maximum current load of the contact

2 A @ 30 V DC (resistive load)

Software interface of input and output

Via GPIOs and process image. Output can optionally be controlled by hardware watchdog.

Hardware watchdog functionality

Can be disabled by bridging the 4-pole screw-type terminal.
Reset by toggling a GPIO or alternatively a bit in the process image.
Trigger interval: approx. 60 seconds without toggling the reset bit.

Compatible RevPi modules

  • All RevPi I/O modules and RevPi gateway modules can be connected via the PiBridge system bus.

  • All RevPi Con modules can be connected via the ConBridge system bus.

ESD protection

4 kV / 8 kV (according to EN 61131-2 and IEC 61000-6-2)

EMI tests

Passed (according to EN 61131-2 and IEC 61000-6-2)

Surge / Burst tests

Passed (according to EN 61131-2 and IEC 61000-6-2)

Buffer time RTC

Min. 24 h

Optical display

6 status LEDs (bi-color), 2 freely programmable

Conformity

CE, RoHS, REACH, UKCA

UL certification

UL-File-No. E494534
NOTE: The device may only be supplied from circuits that comply with Class 2 or Safety Extra Low Voltage (SELV) according to Class 9.4 of UL 61010-1.

Technical Data RevPi Connect SE #

Item No.: 100368, 100369, 100370

Housing dimensions (H × W × D)

96 × 45 × 110.5 mm

Housing type

DIN rail housing for TH35 mounting rail according to DIN EN 60715

Housing material

Polycarbonate

Weight

Approx. 197 g / 224 g (incl. connectors)

Protection class

IP20 / NEMA Class 1

Power supply

Typ. 24 V DC (10.8 … 28.8 V DC)

Maximum power consumption

20 Watt (incl. 1 A total USB output current)[3]

Approved operating temperature

-25 … +55 °C

Approved storage temperature

-40 … +85 °C

Max. relative humidity (at 40 °C)

Up to 93 % (non-condensing)

Interfaces

  • 2 × USB A (total current draw from both sockets max. 1 A)[4]

  • 2 × RJ45 10/100 Ethernet (using separate MAC addresses)

  • 1 × RS485 screw-type terminal

  • 1 × Micro-USB (solely for image transfer to eMMC)

  • 1 × Micro HDMI 2.0a (4K)

  • 1 × PiBridge system bus

  • 1 × ConBridge system bus


4. 1 A USB output current (sum of both USB outputs) is only available with input voltages >11 V. The bridging time of voltage dips of at least 10 ms required by EN 61131-2 is only guaranteed with a supply voltage of 20.4 …28.8 V. At 12 V input voltage this time decreases drastically, especially when driving loads by USB ports.

Connectors

  • 1 × 4-pole screw-type terminal for relay contact and signal input

  • 1 × 4-pole screw-type terminal for power supply

Compute Module

Raspberry Pi Compute Module 4S

Processor

Broadcom BCM2711, quad-core Arm Cortex-A72

Clock rate

1.5 GHz

Processor cooling

Passive with heat sink

RAM

1 GB LPDDR4
NOTE: The Linux GUI should only be used on RevPi devices with at least 2 GB RAM.

Flash memory

8 GB (Item No.: 100368), 16 GB (Item No.: 100369), 32 GB (Item No.: 100370)

Number of digital inputs

1

Digital input type

24 V control voltage (e.g. for power-good signal of a UPS)

Input threshold

Approx. 3.0 V (0 → 1) resp. 2.3 V (1 → 0)

Input protection

Against overvoltage, negative voltages

Number of digital outputs

1

Output type

Relay contact (NC), approval up to 30 V switching voltage (e.g. for power supply of a router)

Maximum current load of the contact

2 A @ 30 V DC (resistive load!)

Software interface of input and output

via GPIOs and process image. Output is optionally switched by hardware watchdog.

Hardware watchdog functionality

Can be disabled by bridging the 4-pole screw-type terminal.
Reset by toggling a GPIO or alternatively a bit in the process image.

Hardware watchdog interval

Trigger after approx. 60 seconds without toggling the reset bit.

Compatible RevPi modules

  • All RevPi I/O modules can be connected via the PiBridge system bus.

  • All RevPi Con modules can be connected via the ConBridge system bus.

  • Not compatible with RevPi Gateways

ESD protection

4 kV / 8 kV (according to EN 61131-2 and IEC 61000-6-2)

EMI tests

Passed (according to EN 61131-2 and IEC 61000-6-2)

Surge/Burst tests

Passed (according to EN 61131-2 and IEC 61000-6-2)

Buffer time RTC

Min. 24 h

Optical display

6 status LEDs (bi-color), two of them freely programmable

Conformity

CE, RoHS, REACH, UKCA

UL certification

UL-File-No. E494534
NOTE: The device may only be supplied from circuits that comply with Class 2 or Safety Extra Low Voltage (SELV) according to Class 9.4 of UL 61010-1.


1. The average power consumption without USB load varies greatly and depends on the use of the interfaces, GPU and CPU. It is usually well below 4 W without HDMI.
3. The average power consumption without USB load varies greatly and depends on the use of the interfaces, the GPU and the CPU. It is usually well below 4 W without HDMI.