Atx: Temperature Sensors Inputs; Aox: Analog Voltage And Current Outputs; Dix: Digital Inputs; Ocx: Open Collector Outputs - Sferalabs Iono Pi Max v2 3+ Lite User Manual

ATx: Temperature sensors inputs

Iono Pi Max has two inputs dedicated to connect two-wire resistance temperature sensors
(RTD). Both Pt100 and Pt1000 standard sensors are supported.
To use these inputs, you should first set the sensor type in analog_in/at<n>_mode (I2C
control register 69). 0 disables, the input, 1 configures a Pt100, and 2 a Pt1000.
Measured temperature values in °C/100 are available in the analog_in/at<n> files (I2C
control registers 79-80, 24 bits resolution, signed two's complement).
The data refresh period for these inputs is 1000ms.

AOx: Analog voltage and current outputs

Two analog outputs can be independently configured as 0-10V voltage or 0-20mA current
drivers. The current outputs are active, as they supply, not sink, current to the current loop.
The driver front-end is based on two Texas Instruments XTR305 industrial analog voltage
and current drivers, driven by the Iono Pi Max SAME54 controller's digital-to-analog
converter.
Sysfs files in the analog_out directory are used to enable the outputs (ao<n>_enabled, I2C
control registers 94, 99), configure the voltage/current operating mode (ao<n>_mode, I2C
control registers 94, 99), set the output levels (ao<n>, I2C control registers 95, 100) and
read the error status from the driver (ao<n>_err, I2C control registers 96, 101). The driver
detects over-temperature, load errors and common mode errors.
The analog outputs are disabled by default.

DIx: Digital inputs

Iono Pi Max has four general purpose digital inputs. These inputs are connected to GPIO
lines of the Compute Module and also to the Iono Pi Max SAME54 controller.
They are protected by a resistor network, and pulled to ground when not connected.
NOTICE
The DIx digital inputs accept positive voltage levels up to 40Vdc. Applying out of range
voltages could damage the product and connected devices.
Read-only sysfs files digital_in/di<n> return the high or low status of these inputs.

OCx: Open collector outputs

Iono Pi Max has four open collector outputs, with open circuit fault detection, and over-
current/short detection and protection, driven by a Maxim MAX4896 8-channel relay and
load driver.
digital_out/oc<n> files (I2C control registers 89-90) are used to set the open collectors
status, and read the status and error conditions.
39 Iono Pi Max User Guide