This driver (located in the Core drivers folder) is designed for use with the ezeio MkII controller and the ezeio MkII I/O Expander. It is ideal for reading resistance (Ohms), and sensors with DC current (0-30 mA) or voltage (0-10 VDC) signals. This driver does support pulse outputs and thermistors, specialized drivers are offered. The settings on this driver map the source, configure circuitry on the ezeio, and produce signal readings, scaled values, a logic value and statuses. An instance of this driver can be added for each available input terminal on the controller or expanders. This method of individually configuring inputs allows the driver's name to reflect a unique sensor or device. Below are descriptions of the various settings.

Name - The name is up to the user. Our suggestion is to choose a naming convention that makes the viewing the device list intuitive. Such as referring to the sensor and/or application. Keep the name short as it will be combined with the register name to create the default “Field” name (if added to “Fields”)

Notes - This space can be used to store information specific to the device, such as: location, wiring, scaling, etc.

Active Check box - Check this box and “Save changes” to run the driver. The driver program can be suspended by unchecking the box and clicking on “Save changes”.

Device - Select the ezeio controller or the device number of a connected ezeio I/O Expander.

Input number - Select the input number (1-8) of the selected device.

Input hardware type - Select the type of sensor or signal type (0-10V, 0-30mA (4-20mA), Ohms, thermistor). Some of the thermistor choices are tailored to specific sensors and others are generic (see the table below for details). Options from pulse are shown, but we recommend using the “Pulse input” driver. The Self test is diagnostic setting to test the circuitry of the input when nothing is connected. The selection will determine the raw to unit conversion for registers 1 & 2 (shown on the “Available registers” table on the right hand panel). These are the pre-scaled values.

REGISTER 1 & 2 SETTINGS - Each discrete input is duplicated, providing the opportunity to process the data it two different ways, such as max & average. The ezeio controller's microprocessor reads the onboard inputs (and those of any docked ezeio I/O Expanders) at a rate of 1000 times per second. These readings are processed and output as samples a the rate of 10 times per second. The table below describes the effects of each mode.

Register 1 & 2 modes - Choose one of the setting below for registers 1 & 2.

SCALING OF REGISTER 1 - Register 1 can be scaled to a unit value such as PSI or LPM. The relationship between the Min/Max raw & scaled settings creates a 2 point linear conversion. The result of this conversion is shown in register 3. In addition, a Low/High error range (in the scaled unit) can be entered, representing a normal or safe operating range for the application.

Min raw - Max raw - By default, the range shown here is set based on the “Input hardware type” selected, such as 0-10V (0.0 - 10.0) or 0-30mA (4.0 - 20.0). This would correlate to the full scale of a typical sensor. These fields can be changed if required to match the output of your sensor or the scale range you wish to use in the next step.

Min scale - Max scale - Enter values here that correlate to the Min/Max raw values. For example: 4.0mA = 0 psi and 20.0mA = 250 psi

Low error - High error - Enter values here that represent the normal range for the application. This could also represent the operating range of the sensor, so a negative value could indicate an open circuit. When the value is out of this range, the “Driver status” will indicate an “App error”. This error can be see on the Driver status, incorporated in expressions by use of ds(DVCSTAT_APPSTAT) and included in messages with the “Message Template Tag” [DVCSTAT#APPSTAT].

SCALING OF REGISTER 2 - This register's scaling utilizes a multiplying factor and an offset. Using the previous example of a 4-20mA output pressure transducer with a range of 0-250 psi, the offset would be 4 and the factor would be 15.625. The result of this scaling of register 2 is shown as register 4

Offset - Set a starting point or floor for the scaling such as 4 in the case of 4-20mA signals.

Factor - Multiply the raw value to create a linear conversion that matches your sensors scale. To find the factor, divide the sensor full scale range by the number of raw unit steps.

LOGIC STATE - This feature converts any ranging analog value into a digital value (or boolean) by defining a threshold beyond which it is consider true (represented by 1, or 100).

Threshold (Scaled) - Enter a threshold value above or below which the state should be considered true (or ON).

Filter time - Filter out transient value changes by entering a number of seconds (and tenths) in this field. The value must then exceed the threshold for the proscribed time before it is considered true.

Logic - Set the true (or ON) state to be above or below the threshold value, with a value of 1 or 100. Choosing 100, make it easy to use the value to drive a digital output via “Fields”.