Usage
The PCB contains the electronics to accommodate all use cases. NTCs can be connected via MOLEX, I2C established via RJ45 and Frequency Counting via a LEMO pin. Additionally all pins are realised using Pin Headers. Every Arduino Pin is also duplicated using Pin Headers.
As the A4 and A5 pins of the Arduino are used for for I2C and the NTC readout a Usage Selection pin header is implemented. Using jumpers one can connect the pins manually. Don't connect I2C and NTC readout at the same time - it might damage your devices and there is no software being able to handle both.
All use cases require a different type of software to be uploaded to the Arduino. All Arduino and matching python scripts can be downloaded from cyclotron-bonn/irradcontrol.
Each of the Arduino's 8 pins (A0-A7) which are connected to the multiplexed ADC can be used to read out an NTC using a voltage divider configuration supplied by the Arduino's 3V3 pin. In order to set this up one has to connect the ADC's voltage reference to 3V3 (marked on PCB), NTC4 to A4 and NTC5 to A5 via jumpers using the Usage Selection`. The positions are marked as red on given figure. Setup and control is done with Python.
The on-board Arduino can be used to translate any incoming Serial message to I2C and vice versa. Communication via I2C is realized with the A4 and A5 pin which act as data channel and clock, respectively. An RJ45 port can be used to connect the module to an external micro controller. Connect SDA to A4 and SCL to A5 using the Usage Selection`. The positions are marked as blue on given figure.
In order to count the frequency voltage pulses one can connect the source to a LEMO connection or pin header with signal and ground. The Arduino Pin servicing as an input is a high-impedance pin which acts as having a 100 MΩ resistor in serial in front of the pin. There is no need to place any jumpers to use this mode.