EnumPoints method

Description

VWorks software calls the EnumPoints method to tell the plugin to enumerate all I/O channels for a device.

Syntax

 

HRESULT EnumPoints( [out] BSTR *ioxml, [out,retval] enum ReturnCode *retVal );

Parameters

 

ioxml	[out] Three XML elements: digitalInputs, analogInputs, and digitalOutputs. Each XML element contains an enumeration array of all digital input, analog input, or digital output channels for a device.
retVal	[out, retval] Returns an error code. Possible values: 0 = The request was completed (RETURN_SUCCESS) 1 = Something was wrong with the input, so the request was not completed (RETURN_BAD_ARGS) 2 = The request was not completed (RETURN_FAIL) For more information, see “ReturnCode enumerated type” .

EnumPoints method output

The plugin returns the following three XML elements in the ioxml parameter of the EnumPoints method:

•	digitalInputs XML element

•	analogInputs XML element

•	digitalOutputs XML element

The value of the file attribute of the Velocity11 element is Velocity11. See “Velocity11 element” .

digitalInputs, analogInputs, or digitalOutputs elements

Each digitalInputs, analogInputs, and digitalOutputs element contains one or more name elements.

Required: No

Default value: An empty string

name element

Each name element contains the name of an input or output channel.

Required: No

Default value: An empty string

Example of EnumPoints method output

The following sample code contains the (truncated) digitalInputs, analogInputs, and digitalOutputs XML elements (with enumeration arrays) that are returned to VWorks software by the plugin as a string in the ioxml parameter of the EnumPoints method.

 

<?xml version='1.0' encoding='ASCII' ?> <Velocity11 file='Velocity11' md5sum='d523224aed7bdf522e1a8901e13d2bf6' →version='1.1' > <digitalInputs > <name >Input 1 for Temperature</name> <name >Input 2 for Humidity</name> <name >Input 3 for Waste bin door</name> ... <name >Input 19 (00-00-00-00-00-00)</name> <name >Input 20 (00-00-00-00-00-00)</name> </digitalInputs> <analogInputs > <name >Fluid level 1</name> <name >Fluid level 2</name> <name >Humidity</name> ... <name >Analog 11 (00-00-00-00-00-00)</name> <name >Analog 12 (00-00-00-00-00-00)</name> </analogInputs> <digitalOutputs > <name >Ventilation fan</name> <name >UV light</name> <name >Alarm (audible)</name> ... <name >Output 15 (00-00-00-00-00-00)</name> <name >Output 16 (00-00-00-00-00-00)</name> </digitalOutputs> </Velocity11>

Related information

 

For information about...	See...
Read method	“Read method”
Set method	“Set method”