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Quickstart Guide 

Pi-oT 2 Precision Series 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Analog Inputs 

The MCP3208 powered inputs communicate 
with the Raspberry Pi via the SPI 0 channel. 
No. of Inputs 

Resolution 

12 Bit 

Voltage Range 

0-5 V 

Common  

AGND 

Sampling Rate 

100 ksps 

Galvanic isolation 

None 

RS485 

The SN65HVD72 powered port converts 
RS485 signals directly to serial logic, allowing 
the Raspberry Pi to communicate with 
standard RS485 devices via pins 14 and 15 
(BCM). 

 

Surge Protection 

≥500

-V surge 

transients 

Termination R. 

0 Ohm 

Bias R. 

0 Ohm 

Galvanic Isolation 

None 

Analog Inputs: 

 

The 8x 0-5V analog inputs interface to 

the Raspberry Pi via the SPI 0 channel. With a 
resolution of 12 Bits, the MCP3208 chip be 
best used with the 

gpiozero

 Python library. 

The MCP3208 IC is also capable of operating 
in differential mode. In this mode one channel 
is read relative to the value of a second 
channel. For more information, refer to the 

gpiozero 

documentation or the MCP3208 

datasheet. 

Note: The AGND pin and GND are connected 
via a 40 Ohm resistor internal to the MCP3208 
IC. The best practice is to operate the Module 
and sensor on the same ground plane. 

RS485 Terminal: 

 

The single RS485 terminal is 

connected to the Raspberry Pi TX and RX 
pins. The circuitry converts the RS485 level 
signals to standard serial level in order for the 
Raspberry Pi to read it. Open-source Python 
Libraries such as 

pyserial 

or 

minimalmodbus 

work best for interpreting the signals. 

 

In order for the Module to be used as a 

Master on an RS485 bus, termination or bias 
resistors are not included in the on-board 
circuit, and thus may need to be implemented 
elsewhere on the bus. 

Summary of Contents for Precision Pi-oT 2

Page 1: ...d secure to the Pi oT Baseboard with 2 Hex Standoffs If active cooling is needed install the 5V fan with the 2 4 40 screws and plug the fan into the 5V header in the top right of the board Next install the UPS Board onto the Pi oT 2 Baseboard by first aligning 2 mounting holes on the UPS Board with the 2 Hex Standoffs This will ensure the 5 pin connector is properly aligned CAUTION If the UPS boar...

Page 2: ... is held High when Vin is present thus allowing the Module to power on when Vin is initially supplied The configuration of these two signals allows for the following logic to control the Module 1 The Raspberry Pi and UPS power on when Vin is first supplied 2 The GPIO pin 24 is held high via a python script or similar 3 GPIO pin 25 is used as an input to monitor for power failure 4 Once GPIO pin 25...

Page 3: ... use extreme care when configuring this device Once configured attach the Positive and GND leads to the screw terminals using a 3 Watt capable power supply Step 5 Interfacing the Raspberry Pi with the Pi oT 2 Baseboard The Pi oT 2 has 4 main IO groups 1 Digital Inputs 2 Digital Outputs 3 Analog Inputs 4 RS485 Digital Inputs The 4x 24 volt inputs are connected the GPIO pins 12 17 22 and 27 When int...

Page 4: ...on library The MCP3208 IC is also capable of operating in differential mode In this mode one channel is read relative to the value of a second channel For more information refer to the gpiozero documentation or the MCP3208 datasheet Note The AGND pin and GND are connected via a 40 Ohm resistor internal to the MCP3208 IC The best practice is to operate the Module and sensor on the same ground plane...

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