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

3

2 × RJ45 Ethernet

RJ45 Ethernet Interfaces,
Establishing a Network Connection

4

Micro-USB

Saving and Reinstalling the 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 I/O Modules #

RevPi Con Modules #

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

See RevPi Gateways

Virtual Devices #

The Virtual Devices are delivered as components in PiCtory:

Operating System Images #

The RevPi Connect S/SE is compatible with:

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.

Connecting the UPS #

A UPS (uninterruptible power supply) ensures that devices continue to function during a fault. Depending on the type of UPS, a UPS can protect against the following faults:

  • Power failure

  • Overvoltage

  • Undervoltage

  • Frequency changes

  • Harmonics

The RevPi has a digital input, to which the status output of a UPS can be connected.

▷ Check whether your UPS is suitable for connection to the RevPi.

▷ Connect the status output of the UPS to the digital input on the X2 connector (pin IN and pin Ground (GND)).

▷ Observe the installation specifications of the UPS manufacturer.

▷ Test the UPS.

In the process image, bit 6 of the RevPiStatus variable is 0 or 1, depending on whether 0V or 24V is applied to the input. Your application must read this bit cyclically. If the UPS reports a problem, your application must initiate a corresponding measure. What exactly should be done depends on:

  • the size of the battery used,

  • the current consumption of the RevPi,

  • the current consumption of all components that are additionally connected to the UPS.

Typically, the system is brought into a safe state and the RevPi is shut down.

Access to the Device #

The RevPi is accessed in two steps:

  1. Establishing a Network Connection.

  2. Login on the device.

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. As of RevPi Bookworm (10/2024) you configure the RevPi base module via the application Cockpit.

  2. You 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.
Note

Until RevPi Bullseye (04/2024), the RevPi base module is configured via the RevPi Status application.

Parameterization #

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: Update firmware.

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.

RS485ErrorCnt (INP) #

Counts the errors in the communication with the RevPi I/O modules and outputs their number 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.

RS485ErrorLimit1 (OUT) and RS485ErrorLimit2 (OUT) #

RS485ErrorLimit1 and RS485ErrorLimit2 serve as threshold values for error handling in the communication between the RevPi device and the I/O modules.

At the end of each communication cycle, the error counter RS485ErrorCnt is compared with these two limit values:

  • RS485ErrorLimit1: When this value is reached, a message is generated in the log file kern.log. In future piControl versions, the default values defined in PiCtory will also be written to the process image.

  • RS485ErrorLimit2: If the error counter reaches this value, PiBridge communication is terminated completely.

Note

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

The respective check is deactivated by setting the corresponding value to 0. If, for example, RS485ErrorLimit1 is set to 0, no warning messages are generated in kern.log.

The default values are:

  • RS485ErrorLimit1: 10

  • RS485ErrorLimit2: 1000

These values offer a good balance between fault tolerance and system stability for most applications.

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

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. Under Linux, the interfaces can be addressed with:

  • 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 %.

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 #

This relay output 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 open after the start.

▷ Make sure 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 the status byte RevPiOutput, bit 6.

Digital Input #

The input has an internal pull-down resistor.

The digital input can be used to connect a UPS.

▷ 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.

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.

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 (RevPiLED, bit 6) bit by bit. 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 DIN rail version EN 50022)

Housing material

Polycarbonate

Weight

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

Protection class

IP20 / NEMA Class 1

Power supply

12 … 24 V DC -15 % / +20 %, reverse-polarity protected

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

Processor

Broadcom BCM2711, quad-core Arm Cortex-A72

Clock rate

1.5 GHz

Processor cooling

Passive with heat sink

RAM

1 GB LPDDR4

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, 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 DIN rail version EN 50022)

Housing material

Polycarbonate

Weight

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

Protection class

IP20 / NEMA Class 1

Power supply

12 … 24 V DC -15 % / +20 %, reverse-polarity protected

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

Processor

Broadcom BCM2711, quad-core Arm Cortex-A72

Clock rate

1.5 GHz

Processor cooling

Passive with heat sink

RAM

1 GB LPDDR4

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, 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.