niagaraDriver-NiagaraProxyExt

This component is an implementation of BProxyExt and applies to controller stations. An alternative for Supervisorstations exists among the virtual components.
Figure 66.   ProxyExt properties
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To view these properties, expand Config > Drivers > NiagaraNetwork > NiagaraStation, right-click Points, click Views > AX Property Sheet, expand a point and double-click its Proxy Ext.

Property Value Description
Device Facets additional properties Determines additional parameters to config facets.
Conversion drop-down list 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

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.
Point Id read-only Reports the point ID.
Subscription Status read-only Reports the subscription status of the component.
Out read-only Displays the current value of the proxy point including facets and status.

The value depends on the type of control point.

Facets define how the value displays, including the value’s number of decimal places, engineering units, or text descriptors for Boolean/enum states. You can edit point facets to poll for additional properties, such as the native statusFlags and/or priorityArray level.

Status reports the current health and validity of the value. Status is specified by a combination of status flags, such as fault, overridden, alarm, and so on. If no status flag is set, status is considered normal and reports {ok}.