Echelon OpenLNS Commissioning Tool - Manual (Page 194)

178 Monitoring and Controlling Networks
Clearing Values
You can clear the displayed value of a network variable or configuration property by right-clicking the
object you want to clear and then clicking Clear Value on the shortcut menu.
To clear all values in the browser display, open the Browse menu and select Clear All Values.
Clearing the values in the browser display does not affect the values in the functional block.
Getting Values
You can get the current value of a network variable or configuration property. To do this, right-click
the network variable or configuration property and then click Get Value on the shortcut menu, or click
the object and then click the Get Value button (
) on the browser toolbar. The new value opens in
the Value column.
To get the current values for all the network variables and configuration properties in the browser
window, open the Browse menu and select Refresh All, or click the Refresh All button (
) on the
browser toolbar. The new values are displayed in the Value column.
Changing a Network Variable or Configuration Property Type
You can change the type of a network variable or configuration property. The network variable or
configuration property type specifies the units and structure of the data contained within the network
variable or configuration property. A network variable or configuration property type is typically fixed
for most devices; however, devices may support network variables and configuration properties with
changeable types as described by the L
ON M ARK Application Layer Interoperability Guidelines.
You can use the OpenLNS CT Browser to change a network variable type. When you change the
network variable type, the browser updates the type in the OpenLNS network database, updates the
type in the physical device if OpenLNS CT is OnNet, and automatically chooses a format for
displaying the network variable data that matches the type, provided one is available. When you
change a network variable type, the Browser also changes the type of any configuration properties that
inherit their type from the network variable. For example, an analog input device may be connected to
a variety of input devices, such as temperature sensors, pressure sensors, or dials. If the input device
measures temperature, a SNVT_temp_f type may be used for its output network variable to define the
value as a temperature. If the device measures air pressure, a SNVT_press_f may be used for its
output network variable to define the value as a pressure. The same device may have SCPTlowLimit1
and SCPThighLimit1 configuration properties that inherit their types from the output network
variable. The browser will change the configuration property type for these SCPTs when you change
the output network variable type.
Not all network variables have changeable types, so check the documentation of the device and
functional block you are browsing to determine whether the Browser will allow you to change the type
of a specific network variable.
Network variables with a changeable type will always have an associated SCPTnvType configuration
property (in the case of some Echelon devices, a UCPTnvTypeInfo configuration property defined in
the Echelon resource file set) that keep track of their type. When you change a network variable type
using the OpenLNS CT Browser, OpenLNS CT updates this configuration property.
To change a network variable type in the OpenLNS CT Browser, right-click the network variable and
then click Change Type on the shortcut menu. This menu item is only available for network variables
with changeable types. The Select Network Variable Type dialog opens.
You cannot change a network variable type if the network variable is connected or being monitored by
OpenLNS CT. Trying to change the type of a network variable that is connected or being monitored
by OpenLNS CT generates an error in the Browser.