Raspberry Pi can read 26 Input signals through the GPIO header, but sometimes you might need to read more. Since all GPIO pins are wired directly to the local processor, some hardware is required to connect them to the real world.
The card has 16 optically isolated Digital Inputs. Input ranges can be jumper-selected for each channel, from 3 volts to 48 volts. Digital Inputs can read both DC and AC signals. The card communicates with Raspberry Pi using only the I2C port, leaving all the other 24 GPIO pins available for your use. It has also an RS-485 port, a power LED and a push button that can be used to shut down the Raspberry Pi. Pluggable connectors make the 16-INPUTS card easy to use when multiple cards are stacked up.
COMPATIBILITY
The card is compatible with all Raspberry Pi versions from Zero to 5. All stacked cards share the 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.
POWER REQUIREMENTS
The card needs 5V to operate and can be powered from Raspberry Pi or from it's own 2 pin pluggable connector. The card draws 10mA. If power is applied to the 2 pin pluggable connector, no other power supply is needed for the Raspberry Pi.
LED INDICATORS
A power LED shows when power is applied to the board. Sixteen LEDs show the status of the inputs.
STACKING MULTIPLE CARDS
Up to eight Sixteen LV Digital Inputs cards can be stacked on your Raspberry Pi. Three positions of the configuration DIP Switch labeled ID0, ID1, ID2 are used to select the stack level. Cards can be stacked in any order.
RESET PUSHBUTTON
Shutting down the Raspberry Pi by turning off the power can result in SD Card failure. To prevent this, a shutdown command needs to be used before power cut-off. But this requires a monitor, keyboard and mouse connected to the Pi.
A momentary on push button installed at the edge of the Sixteen LV Digital Inputs card provides a convenient way to shut down the Raspberry Pi. The button is routed to pin 37 (GPIO 26). You need to write a script which monitors this pin, and if pressed for more than a desired time, issues the shut-down command.
RS485 PORT
An RS485 transceiver enables the Raspberry Pi to connect to other industrial sensors or actuators. In order to use the RS485 port, a jumper needs to be installed on the RXD line going to Raspberry Pi. The jumper is marked RS485 in the layout below. If the jumper is not installed, the RXD line from Raspberry Pi can be used as GPIO.
CARD LAYOUT
ELECTRICAL SPECIFICATIONS
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Power Supply: 5V/8A pluggable connector with reverse polarity protection
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On board resettable fuse: 3A
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Opto-isolated Digital Inputs:
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Input Forward Current: Typical 5 mA, maximum 50 mA
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Low Voltage Input Series Resistor: 2.2K
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Isolation Voltage between inputs and ground: 5,000Vrms
MECHANICAL SPECIFICATIONS
