Resistive Input points

This is a NumericPoint that reads a resistive signal within a 0-to-100K ohm range and produces either an ohms value or a linear, scaled output value.

Figure 425. Resistive Input tab

You access this view from the main menu by clicking Controller Setup > Remote Devices > Remote Drivers, followed by double-clicking the NrioNetwork driver, selecting and double-clicking a module, clicking the Point Manager link, followed by clicking the hyperlink to the right end of the Restive Input point.

Property	Value	Description
Facets	additional properties	Refer to Resistive Input Facets.
Proxy Ext	additional properties	Refer to Resistive Input Proxy Ext properties.
Out	read-only	Reports the current value of the proxy point and its status.
linearCalibration	additional properties	Refer to Resistive Input, Linear Calibration Ext properties.

Resistive Input Facets

Facets determine how a point’s value displays in the station. Resistive input facets include a minimum, maximum, and decimal precision.

Figure 426. Resistive Input Facets and Edit facets window

The Edit window opens when you click the Edit button.

Property	Value	Description
Quantity	drop-down list	Defines the formula.
Unit	defaults to ohm	Configures the default unit.
Max	number, defaults to Infinity	Defines the maximum ohm value.
Min	number, defaults to negative Infinity	Defines the minimum ohm value.
Precision	number, defaults to one	Defines the number of decimal places allowed.

Resistive Input Proxy Ext properties

These properties configure the proxy point extension.

Figure 427. Resistive Input Proxy Ext properties

In addition to the standard properties (Status, Fault Cause, and Enabled), these properties support resistive input proxy extensions.

Property	Value	Description
Conversion	Drop-down list (defaults to `Default`)	Defines how the system converts proxy extension units to parent point units. `Default` automatically converts similar units (such as Fahrenheit to Celsius) within the proxy point. NOTE: In most cases, the standard `Default` conversion is best. `Linear` applies to voltage input, resistive input and voltage output writable points. Works with linear-acting devices. You use the Scale and Offset properties to convert the output value to a unit other than that defined by device facets. `Linear With Unit` is an extension to the existing linear conversion property. This specifies whether the unit conversion should occur on “Device Value” or “Proxy Value”. The new linear with unit convertor, will have a property to indicate whether the unit conversion should take place before or after the scale/offset conversion. `Reverse Polarity` applies only to Boolean input and relay output writable points. Reverses the logic of the hardware binary input or output. `500 Ohm Shunt` applies to voltage input points only. It reads a 4-to-20mA sensor, where the Ui input requires a 500 ohm resistor wired across (shunting) the input terminals. `Tabular Thermistor` applies to only a Thermistor input point and involves a custom resistance-to-temperature value response curve for Type 3 Thermistor temperature sensors. `Thermistor Type 3` applies to an Thermistor Input point, where this selection provides a “built-in” input resistance-to-temperature value response curve for Type 3 Thermistor temperature sensors. `Generic Tabular` applies to non-linear support for devices other than for thermistor temperature sensors with units in temperature. Generic Tabular uses a lookup table method similar to the “Thermistor Tabular” conversion, but without predefined output units.
Tuning Policy Name	drop-down list (defaults to `Default Policy`)	Selects a network tuning policy by name. This policy defines stale time and minimum and maximum update times. During polling, the system uses the tuning policy to evaluate both write requests and the acceptability (freshness) of read requests.
Read Value	read-only	Displays the last value read from the device, expressed in device facets.
Write Value	read-only (applies to writable types only)	Displays the last value written using device facets.
Poll Frequency	drop-down list (defaults to `Normal`)	Selects among three rates (Fast, Normal and Slow) to determine how often to query the component for its value. The network’s Poll Service or Poll Scheduler defines these rates in hours, minutes and seconds. For example: `Fast` may set polling frequency to every second. `Normal` may set poll frequency to every five seconds. `Slow` may set poll frequency to every 30 seconds. This property applies to all proxy points.
Instance	number	Defines the point’s I/O terminal address based on its hardware type. If duplicated (same instance as same hardware type, same board), the point reports a fault status. If an edit attempt is made to an instance already in use by another proxy point, the system discards the edit, and retains the previous instance value.
Ui Type	read-only	Identifies the Nrio Universal Input point type: Resistive Input, Boolean Output, etc.

Resistive Input, Linear Calibration Ext properties

These properties calibrate the calculated resistence value before it is applied to the Out slot, where [(calculatedValue x Scale) + Offset] = Out value. Usage is optional, although Offset and Units are commonly configured.

NOTE: In most cases where the parent Nrio proxy point’s facets have been changed from defaults, you must edit the Units value in this extension to match the units in the point facets, otherwise the parent proxy point reports a fault for status!Typically, you see this fault status immediately after you add a new input point, for example a VoltageInputPoint or ResistanceInputPoint, and configure it with a Linear conversion type (including a scale and offset), and then specify the point’s facets. It may not be immediately clear that the problem is in this Linear Calibration Ext, where you must match its Units value to the units in the point’s facets.

Figure 428. Resistive Input Linear Calibration properties

Property	Value	Description
Scale	number, defaults to 1.0	Defines a scale value. Usually you leave this value set to the default. One exception is if you copied this extension under a CounterInputPoint for the purpose of returning a scaled total.
Offset	positive or negative number, defaults to 0.0	Can compensate for signal error introduced by sensor wiring resistance. If under a CounterInputPoint, leave it at zero (0).
Units	drop-down list	Defines the unit of measure. Should be the same as the parent proxy point’s facets.
Fault Cause	read-only	Indicates the reason why a system object (network, device, component, extension, etc.) is not working (in fault). This property is empty unless a fault exists.