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This interface includes methods and properties of the
communication ports. Typically you open port object,
passing port configuration in the Settings parameter
of the Open() method, perform data exchange and, finally,
close port object. Use IsActive property to determine
whether port is ready for communication, Read and Write
methods to send and receive data.
| Kind | Name | ID | Description |
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Open | 101 | Opens communication port |
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Close | 102 | Closes communication port |
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Read | 103 | Reads string from the communication port |
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Write | 104 | Writes string to the communication port |
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IsActive | 105 | Changes port active (opened) state |
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IsVisible | 106 | Changes port terminal visibility |
| function Open(Settings): VOID |
For DMINIFile, Open method opens selected INI file (Name parameter) and fills Values collection with either section names or parameter names. Open() includes some name parsing: section name (if any) should be delimited by * character from file name and by # character for URLs.
For DMRegistry, Name parameter must be full path to the selected registry key. Use RegEdit to copy-and-paste appropriate values.
WARNING: because of security reasons, the functionality of DMRegistry intentionally limited to those operations required by DM2003. In particlar, root key is ALWAYS read-only, some other keys are just unavailable.
DMDLLHelper, DMINIFile and DMRegistry Open() returns True if operation successfull, and False otherwise. For URLs DMINIFile.Open always return True, and INI file always is read-only.
For DMIEEE488Port, DMClientSocket, DMComPort and DMComTerminal Settings parameters of the Open() method determine port settings. It doesn't return any result. Notice that DMClientSocket, DMComPort and DMComTerminal support "binary" mode of communication.
' DMINIFile:
if DMINIFile.Open("C:\MyFile.ini", false) then
if DMINIFile.Open("http://server/path/file.txt#Columns", true) then
' DMRegistry:
const Key="HKEY_CURRENT_USER\Software\RRR\DM2003\Data Master"
if DMRegistry.Open(Key, true) then
' DMComPort, DMComTerminal:
' open COM4, 9600bps, no parity, 8 data bits, 1 stop bit, character mode
call DMComPort.Open("4,9600,0,8,0,0") ' full string
call DMComPort.Open("4") ' short string
' or use array of parameters
dim Settings(5)
Settings(0)=4 ' COM port number 1, 2, ...
Settings(1)=9600 ' baud rate (300, 600, ... 256000)
Settings(2)=0 ' parity: 0=None, 1=Odd, 2=Even, 3=Mark, 4=Space
Settings(3)=8 ' data bits: 5..8
Settings(4)=0 ' stop bits: 0=OneStopBit, 1=One5StopBits, 2=TwoStopBits
Settings(5)=0 ' mode: -1=binary, 0=character (default)
call DMComPort.Open(Settings)
' DMIEEE488Port:
call DMIEEE488Port.Open("IEEECTRL") ' open command file
call DMIEEE488Port.Open(True) ' open command file
call DMIEEE488Port.Open("IEEEDATA") ' open data file
call DMIEEE488Port.Open(False) ' open data file
' DMDLLHelper:
if DMDLLHelper.Open("C:\path\APIdescription.ini") then
' CPortLibX2, CoCPortLib2:
ComPort1.Open 1, 9600, 0, 8, 0
| function Close: VOID |
For DMDocument, this procedure closes document window. It is similar to Window|Close menu command.
For DMIEEE488Port, DMClientSocket, DMComPort and DMComTerminal, Close method closes the appropriate communication port.
DMDLLHelper.Close unloads DLL so that all subsequent API calls become impossible.
| function Read: Variant |
For DMComPort, DMComTerminal and DMClientSocket this method not supported since read operations for RS232 and TCP/IP are essentially asynchronous. Use OnRead event handler to obtain data from these port controls.
For DMIEEE488Port Read method returns data from the appropriate port or empty string if port is not open.
| function Write(Data): VOID |
Note: for DMComPort and DMComTerminal objects, Write method fires OnError event if port is not open! Data parameter may be either string or array of bytes. The latter mode ("binary") allows you to transmit arbitrary data, including null (0x00) character.
dim Arr(3), Str Arr(0)=65 Arr(1)=84 Arr(2)=13 Arr(3)=10 Str="AT" & vbCrLf call DMComPort.Write(Arr) ' binary mode write call DMComPort.Write(Str) ' character mode write
| property IsActive: Boolean |
This property indicates whether appropriate component was successfully opened. For example, Open() method prepares hardware port or instrument driver for communication. Typically you open component, perform data exchange (invoke methods) and, finally, close the component.
| property IsVisible: Boolean |
IsVisible property determines whether appropriate object is visible on the screen. Note that for ActiveX controls embedded in the HTML page, you can also change Object.style.visibility property. Some controls like DMClientSocket, DMIEEE488Port and DMComPort are invisible by design and don't implement this property.