Opens a connection to a Sealevel I/O module.
- Parameters:
-
| [out] | handle | SeaMAX handle. This integer will be filled with a valid handle for future SeaMAX operations after a successfull open. |
| [in] | connection | String representing the connection to open. For Modbus TCP, the ":502" does not have to be specified. |
- Return values:
-
| 0 | Success. |
| -1 | Parameter 'connection' is null. |
| -2 | Could not determine connection type. |
| -3 | Invalid connection string. |
| -10 | Serial: Invalid or unavailable serial connection. |
| -11 | Serial: Unable to acquire a valid mutex. |
| -12 | Serial: Unable to set serial timeouts. |
| -13 | Serial: Unable to set serial parameters (e.g. baudrate, parity, etc.). |
| -14 | Serial: Invalid serial name parameter. |
| -20 | Ethernet: Could not resolve host address. |
| -21 | Ethernet: Host refused or unavailable. |
| -22 | Ethernet: Could not acquire free socket. |
| -23 | Ethernet: Could not acquire a valid mutex. |
| -30 | SeaDAC Lite: Invalid or unavailable port |
| -31 | SeaDAC Lite: Unable to aquire a mutex handle |
| -32 | SeaDAC Lite: Invalid device number (should be zero or greater). Object invalid. |
| -33 | SeaDAC Lite: Could not read Vendor ID |
| -34 | SeaDAC Lite: Could not read Product ID |
| -40 | Could not read USB device product or vendor ID. |
| -41 | Non-Sealevel USB device. |
| -42 | SeaMAX does not support this Sealevel USB device. |
The connection parameter can be in many different forms. For instance, a COM based product such as a SeaI/O module can be opened with a connection string of the form "COMx" or "\\.\COMx". For an Ethernet connection, such as the SeaI/O E or W series module, a connection string formatted as "x.x.x.x:y" for a dotted notation socket and port connection, or "x:y" for a host name and port will suffice. If the 'y' (TCP/IP port) part of the connection is not specified, the default Modbus TCP port of 502 will be selected as default.
For example, "COM3" or "\\.\COM47" is appropriate for a serial connection, while "10.0.0.1" is appropriate for a socket-based connection.
- Note:
- For Modbus compliant devices (such as the SeaI/O modules), a default slave ID of 247 is used for all SeaMAX functions. To read, write, or configure a module at an address other than 247, please refer to the SM_SelectDevice() function for more details.
A default local COM port baudrate of 9600 bps is chosen for any serial connection. If your I/O device communicates at a rate other than this, please use the SM_ConfigureSerialConnection().
For a SeaDAC Lite model device, the connection string should be formatted as "SeaDAC Lite x" where x is a number. Care should be taken to check to ensure that the device could be opened. For instance, assuming a PC has a SeaDAC Lite device installed, "SeaDAC Lite 0" would open the first one available.
- Note:
- The connection parameter string is case sensitive. Some attempt at parameter checking is made, but it is probable that a malformed string will be successfully added as an TCP/IP connection. Therefore, care should be taken to ensure proper string formatting when opening connections.
- Warning:
- The handle returned by SM_Open is not compatible with any of the other SeaMAX modules such as the SME (Ethernet Configuration) module or the SeaDAC SDL module. Only functions beginning with SM_ should use the handle returned by SM_Open().
