SEQUENT MICROSYSTEMS 0104110000076748 Building Automation Card for Raspberry Pi User Guide

SEQUENT MICROSYSTEMS 0104110000076748 Building Automation Card for

Raspberry Pi

Product Information

The Building Automation Card for Raspberry Pi is a versatile card that allows users to add various inputs and outputs to their Raspberry Pi. It comes with eight jumper settable universal inputs that can be configured to read 0-10V signals, contact closure counters, or 1K/10K temperature sensors. The card also features four general-purpose LEDs that can be controlled through software to indicate the status of inputs, outputs, or external processes. Additionally, it includes an RS-485 transceiver for communication and a power supply for both the card and the Raspberry Pi.

Product Usage Instructions

1. Start by plugging the Building Automation Card on top of your
   Raspberry Pi and power up the system.

2. Enable I2C communication on the Raspberry Pi using
   raspi-config.

3. Install the software from github.com by following these steps:

   • Open the terminal and enter the command: git clone <https://github.com/SequentMicrosystems/megabas-rpi.git>

   • Change the directory to the cloned repository: cd/home/pi/megabas-rpi.

   • Install the software with administrative privileges: sudomake install

4. Run the program by entering the command:  megabas

5. Refer to the program’s list of available commands for further configuration and usage.

Please note that when using multiple Building Automation Cards, it is recommended to use a single 24VDC/AC power supply to power all the cards. The user must split the cable and run the wires to each card. The power consumption of the card is 50 mA at +24V.

GENERAL DESCRIPTION

• The second generation of our Building Automation Card brings to the Raspberry Pi platform all the inputs and outpus required for Building Automation Systems. Stackable to 8 levels, the card works with all Raspberry Pi versions, from Zero to
• Two of the Raspberry Pi’s GPIO pins are used for I2C communication. Another pin is allocated for the interrupt handler, leaving 23 GPIO pins available for the user.
• Eight universal inputs, individually selectable, let you read 0-10V signals, count contact closures, or measure temperatures using 1K or 10K thermistors. Four 0-10V programmable outputs can control light dimmers or other industrial devices. Four 24VAC outputs can control AC relays or heating and cooling equipment. LED indicators show status of all outputs. Two RS485/MODBUS ports permit almost unlimited expandability.
• TVS diodes on all inputs protect the card for external ESD. Onboard resettable fuse protects it from accidental shorts.

FEATURES

• Eight jumper settable universal, analog/digital inputs
• 0-10V Inputs or
• Contact Closure Counter Inputs or
• 1K/10K Temperature Sensor Inputs
• Four 0-10V Outputs
• Four TRIAC Outputs with 1A/48VAC drivers
• Four General Purpose LED’s
• RS485 in and out ports
• Real time clock with battery backup
• On-board push-button
• TVS protection on all inputs
• On-board Hardware Watchdog
• 24VAC power supply

All inputs and output use pluggable connectors which permit easy wiring access when multiple cards are stacked. Up to eight Building Automation Cards can be stacked on top of one Raspberry Pi. The cards share a serial I2C bus using only two of the Raspberry Pi’s GPIO pins to manage all eight cards. This feature leaves the remaining 24 GPIOs available for the user.
The four general purpose LED’s can be associated with the analog inputs or other controlled processes. An on-board push button can be programmed to cut inputs, override outputs or shut down the Raspberry Pi

WHAT IS IN YOUR KIT

1. Building Automation Card for Raspberry Pi
2. Mounting hardware
   • a. Four M2.5x18mm male-female brass standoffs
   • b. Four M2.5x5mm brass screws
   • c. Four M2.5 brass nuts
3. Two jumpers. You do not need the jumpers when using only one Building Automation Card. See STACK LEVEL JUMPERS section if you plan to use multiple cards.
4. All the required female mating connectors.

QUICK START-UP GUIDE

1. Plug your Building Automation Card on top of your Raspberry Pi and power up the system.
2. Enable I2C communication on Raspberry Pi using raspi-config.
3. Install the software from github.com:
4. a. ~$ git clone https://github.com/SequentMicrosystems/megabas-rpi.git
5. b. ~$ cd /home/pi/megabas-rpi
6. c. ~/megabas-rpi$ sudo make install
7. ~/megabas-rpi$ megabas
   The program will respond with a list of available commands.

BOARD LAYOUT

Four General Purpose LEDs can be controlled in software. The LEDs can be activated to show the status of any input, output or external process.

STACK LEVEL JUMPERS
The left three position of the connector J3 are used to select the stack level of the card:

INPUT SELECTION JUMPERS
The eight universal inputs can be individually jumper selected to read 0-10V, 1K or 10K thermistors or contact closure/event counters. The maximum frequency of event counters is 100 Hz.

RS-485/MODBUS COMMUNICATION
The Building Automation Card contains a standard RS485 transceiver which can be accessed both by the local processor and by Raspberry Pi. The desired configuration is set from three bypass jumpers on configuration connector J3.

If jumpers are installed, Raspberry Pi can communicate with any device with an RS485 interface. In this configuration the Building Automation Card is a passive bridge which implements only the hardware levels required by the RS485 protocol. To use this configuration, you need to tell the local processor to release control of the RS485 bus:

• ~$ megabas [0] wcfgmb 0 0 0 0

If jumpers are removed, the card operates as MODBUS slave and implements the MODBUS RTU protocol. Any MODBUS master can access all the card’s inputs, and set all the outputs using standard MODBUS commands. A detailed list of commands implemented can be found on GitHub: https://github.com/SequentMicrosystems/megabas-rpi/blob/master/Modbus.md
In both configurations the local processor needs to be programmed to release (jumpers installed) or control (jumpers removed) the RS485 signals. See the command line online help for further information.

RASPBERRY PI HEADER

POWER REQUIREMENTS
The Building Automation Card requires an external 24VDC/AC regulated power supply. Power is supplied to the board through the dedicated connector in the upper right corner (see BOARD LAYOUT). The boards accepts either DC or AC power source. If a DC power source is used, polarity is not important.

A local 5V regulator supplies up to 3A power to Raspberry Pi, and a 3.3V regulator powers the digital circuits. Isolated DC-DC converters are used to power the relays.
WE RECOMMEND USING ONLY THE 24VDC/AC POWER SUPPLY TO POWER THE RASPBERRY PI CARD

If multiple Building Automation Cards are stacked on top of each other, we recommend using a single 24VDC/AC power supply to power all the cards. The user must split the cable and run the wires to each card.

POWER CONSUMPTION:

• 50 mA @ +24V

UNIVERSAL INPUTS
The Building Automation Card has eight universal inputs which can be jumper selected to measure 0-10V signals, 1K or 10K thermistors or contact closure/event counters up to 100Hz.

0-10V INPUTS CONFIGURATION

EVENT COUNTER/CONTACT CLOSURE CONFIGURATION

TEMPERATURE MEASUREMENT CONFIGURATION WITH 1K THERMISTORS

TEMPERATURE MEASUREMENT CONFIGURATION WITH 10K THERMISTORS

0-10V OUTPUTS CONFIGURATION. MAX LOAD = 10mA

TRIAC OUTPUTS CONFIGURATION. MAX LOAD = 1A

HARDWARE WATCHDOG

• The Building Automation Card contains a built-in hardware watchdog which will guarantee that your mission-critical project will continue running even if Raspberry Pi software hangs up. After power up the watchdog is disabled, and becomes active after it receives the first reset.
• The default timeout is 120 seconds. Once activated, if it does not receive a reset from Raspberry Pi within 2 minutes, the watchdog cuts the power and restores it after 10 seconds.
• Raspberry Pi needs to issue a reset command on the I2C port before the timer on the watchdog expires. The timer period after power up and the active timer period can be set from the command line. The number of resets is stored in flash and can be accessed or cleared from the command line. All the watchdog commands are described by the online help function.

ANALOG INPUTS/OUTPUTS CALIBRATION
All the analog inputs and outputs are calibrated at the factory, but firmware commands permit the user to re-calibrate the board, or to calibrate it to better precision. All inputs and outputs are calibrated in two points; select the two points as close to possible to the two ends of scale. To calibrate the inputs, the user must provide analog signals. (Example: to calibrate 0-10V inputs, the user must provide a 10V adjustable power supply). To calibrate the outputs, the user must issue a command to set the output to a desired value, measure the result and issue the calibration command to store the value.

The values are stored in flash and the input curve is assumed to be linear. If a mistake is made during calibration by typing the wrong command, a RESET command can be used to reset all the channels in the corresponding group to factory values. After RESET calibration can be restarted.

The board can be calibrated without a source of analog signals, by calibrating first the outputs and then routing the calibrated outputs to corresponding inputs. The following commands are available for calibration:

• CALIBRATE 0-10V INPUTS: megabas cuin
• RESET CALIBRATION OF 0-10V INPUTS: megabas rcuin
• C ALIBRATE 10K INPUTS: megabas cresin
• RESET 10K INPUTS: megabas rcresin
• CALIBRATE 0-10V OUTPUTS: megabas cuout
• STORE CALIBRATED VALUE IN FLASH: megabas alta_comanda
• RESET CALIBRATION OF 0-10V OUTPUTS: megabas rcuout

HARDWARE SPECIFICATIONS

ON BOARD RESETTABLE FUSE

0-10V INPUTS:

• Maximum Input Voltage: 12V
• Input Impedance: 20KΩ
• Resolution: 12 bits
• Sample rate: tbd

CONTAC CLOSURE INPUTS

• Maximum count frequency: 100 Hz

0-10V OUTPUTS:

• Minimum Output Load: 1KΩ
• Resolution: 1 3 BITS

TRIAC OUTPUTS:

• Maximum Output Current: 1A
• Maximum Output Voltage: 120V

LINEARITY OVER FULL SCALE

• Analog inputs are processed using 12 bit A/D converters internal to the on-board processor. The inputs are sampled at 675 Hz.
• Analog outputs are PWM synthesized using 16 bit timers. PWM values range from 0 to 4,800.
• All inputs and outputs are calibrated at test time at the end points and values are stored in flash.
• After calibration we checked the linearity over full scale and obtained the following results:

Channel/Max/Error %

• 0-10V IN: 15μV:0.15%
• 0-10V: OUT: 10μV 0.1%

MECHANICAL SPECIFICATIONS

SOFTWARE SETUP

1. Have your Raspberry Pi ready with the latest OS.

2. Enable I2C communication:
   ~$ sudo raspi-config

   • Change User Password Change password for default user
   • Network Options Configure network settings
   • Boot Options Configure options for start-up
   • Localisation Options Set up language and regional settings to match..
   • Interfacing Options Configure connections to peripherals
   • Overclock Configure overclocking for your Pi
   • Advanced Options Configure advanced settings
   • Update Update this tool to the latest version
   • About raspi-config Information about this configuration
   • P1 Camera Enable/Disable connection to the Raspberry Pi Camera
   • P2 SSH Enable/Disable remote command line access to your Pi
   • P3 VNC Enable/Disable graphical remote access to your Pi using…
   • P4 SPI Enable/Disable automatic loading of SPI kernel module
   • P5 I2C Enable/Disable automatic loading of I2C kernel module
   • P6 Serial Enable/Disable shell and kernel messages to the serial port
   • P7 1-Wire Enable/Disable one-wire interface
   • P8 Remote GPIO Enable/Disable remote access to GPIO pins

3. Install the megabas software from github.com:

   • ~$ git clone https://github.com/SequentMicrosystems/megabas-rpi.git

4. 4. ~$ cd /home/pi/megabas-rpi

5. 5. ~/megaioind-rpi$ sudo make install

6. 6. ~/megaioind-rpi$ megabas
   The program will respond with a list of available commands.

Type “megabas -h” for online help.
After installing the software, you can update it to the latest version with the commands:

• ~$ cd /home/pi/megabas-rpi
• ~/megabas-rpi$ git pull
• ~/megabas-rpi$ sudo make install

References

• GitHub: Let’s build from here · GitHub
• Home, Industrial & Building Automation I/O HATS for Raspberry Pi
• GitHub - SequentMicrosystems/megabas-rpi: Command Line, Python lib, Node-Red and CODESYS driver for Building Automation Card

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