Working with Analog IO

This guide covers analog inputs and outputs on ED-series devices that support analog IO, including data formats, temperature measurement, and delta/target events.

Analog Devices

Not all ED-series devices have analog IO. The following devices support analog lines:

Device	Analog Lines	Type
ED-549	8 analog inputs	Voltage or current
ED-560	4 analog outputs	Voltage or current
ED-582	4 RTD inputs	Temperature (PT100/PT1000)
ED-593	8 thermocouple inputs	Temperature

Reading Analog Inputs

Use the AValue property to read analog values:

using Brainboxes.IO;

using (EDDevice ed = EDDevice.Create("192.168.0.100"))
{
    // Read a single analog input
    double value = ed.AInputs[0].AValue;
    Console.WriteLine($"Analog input 0: {value}");

    // Read all analog inputs
    for (int i = 0; i < ed.AInputs.Count; i++)
    {
        Console.WriteLine($"Analog input {i}: {ed.AInputs[i].AValue}");
    }
}

Like digital values, analog values are cached for IOLineCacheTimeout milliseconds (default 250 ms) and reading any line refreshes all analog lines in one network call.

Setting Analog Outputs

On the ED-560 (4 analog outputs):

using (EDDevice ed = EDDevice.Create("192.168.0.100"))
{
    // Set analog output 0 to 5.0 (units depend on AnalogDataFormat)
    ed.AOutputs[0].AValue = 5.0;
}

Data Formats

The AnalogDataFormat enum controls how analog values are interpreted:

Format	Description
Engineering	Real-world units (volts, milliamps, degrees)
FullScaleRange	Percentage of full-scale range (0.0 – 100.0)
Hexadecimal	Raw ADC value in two's complement

Set the data format through the protocol:

using (EDDevice ed = EDDevice.Create("192.168.0.100"))
{
    ASCIIProtocol protocol = (ASCIIProtocol)ed.Protocol;

    // Read in engineering units (default)
    protocol.SetAnalogDataFormat(AnalogDataFormat.Engineering);
    double voltage = ed.AInputs[0].AValue; // e.g. 3.245 (volts)

    // Read as percentage of full-scale range
    protocol.SetAnalogDataFormat(AnalogDataFormat.FullScaleRange);
    double percent = ed.AInputs[0].AValue; // e.g. 32.45 (%)
}

Temperature Measurement

The ED-582 (RTD) and ED-593 (thermocouple) devices measure temperature. The TemperatureUnit enum controls the unit:

Unit	Description
Celsius	Degrees Celsius
Fahrenheit	Degrees Fahrenheit
Kelvin	Degrees Kelvin

using (EDDevice ed = EDDevice.Create("192.168.0.100"))
{
    ASCIIProtocol protocol = (ASCIIProtocol)ed.Protocol;

    // Read temperature in Celsius
    protocol.SetTemperatureUnit(TemperatureUnit.Celsius);
    double tempC = ed.AInputs[0].AValue;
    Console.WriteLine($"Temperature: {tempC} °C");

    // Read temperature in Fahrenheit
    protocol.SetTemperatureUnit(TemperatureUnit.Fahrenheit);
    double tempF = ed.AInputs[0].AValue;
    Console.WriteLine($"Temperature: {tempF} °F");
}

Analog Events

Analog lines support three types of events for change notification. Unlike digital events, analog events require explicit subscription with threshold parameters.

Delta Events

Fire when the value changes by more than a specified amount:

using (EDDevice ed = EDDevice.Create("192.168.0.100"))
{
    AIOLineChangedEventHandler handler = (line, device, value, changeType) =>
    {
        Console.WriteLine($"Analog {line.IONumber} changed to {value}");
    };

    // Notify when value changes by more than 0.5
    ed.AInputs[0].SubscribeToDeltaEvent(ref handler, delta: 0.5);

    Console.ReadKey();

    ed.AInputs[0].UnsubscribeToDeltaEvent(ref handler);
}

Target Events

Fire when the value crosses a specified threshold:

AIOLineChangedEventHandler handler = (line, device, value, changeType) =>
{
    if (changeType == AIOChangeTypes.Above)
        Console.WriteLine($"Value went above target: {value}");
    else if (changeType == AIOChangeTypes.Below)
        Console.WriteLine($"Value went below target: {value}");
};

// Notify when value crosses 3.3V
ed.AInputs[0].SubscribeToTargetEvent(ref handler, target: 3.3);

Target Range Events

Fire when the value enters or exits a range around a target:

AIOLineChangedEventHandler handler = (line, device, value, changeType) =>
{
    if (changeType == AIOChangeTypes.Enter)
        Console.WriteLine($"Value entered range: {value}");
    else if (changeType == AIOChangeTypes.Exit)
        Console.WriteLine($"Value left range: {value}");
};

// Notify when value enters/exits the range 3.3 ± 0.2
ed.AInputs[0].SubscribeToTargetRangeEvent(ref handler, target: 3.3, delta: 0.2);

AIOChangeTypes

Value	Event Type	Meaning
Delta	Delta	Value changed by more than the delta threshold
Above	Target	Value crossed above the target
Below	Target	Value crossed below the target
Enter	Target Range	Value entered the target ± delta range
Exit	Target Range	Value left the target ± delta range