Channel Properties — Serial Communications
Serial communication properties are available to serial drivers and vary depending on the driver, connection type, and options selected. Below is a superset of the possible properties.
Click to jump to one of the sections: Connection Type, Serial Port Settings or Ethernet Settings, and Operational Behavior.
Notes:• With the server's online full-time operation, these properties can be changed at any time. Utilize proper user role and privilege management to prevent operators from changing properties or accessing server features.
• Users must define the specific communication parameters to be used. Depending on the driver, channels may or may not be able to share identical communication parameters. Only one shared serial connection can be configured for a Virtual Network (see Channel Properties — Serial Communications).
Connection Type
Physical Medium : Choose the type of hardware device for data communications. Options include Modem, Ethernet Encapsulation, COM Port, and None. The default is COM Port.
1. None : Select None to indicate there is no physical connection, which displays the Operation with no Communications section.
3. Modem : Select Modem if phone lines are used for communications, which are configured in the Modem Settings section.
4. Ethernet Encap. : Select if Ethernet Encapsulation is used for communications, which displays the Ethernet Settings section.
5. Shared : Verify the connection is correctly identified as sharing the current configuration with another channel. This is a read-only property.
Serial Port Settings
COM ID: Specify the Communications ID to be used when communicating with devices assigned to the channel. The valid range is 1 to 9991 to 16. The default is 1.
Baud Rate: Specify the baud rate to be used to configure the selected communications port.
Data Bits: Specify the number of data bits per data word. Options include 5, 6, 7, or 8.
Parity: Specify the type of parity for the data. Options include Odd, Even, or None.
Stop Bits: Specify the number of stop bits per data word. Options include 1 or 2.
Flow Control: Select how the RTS and DTR control lines are utilized. Flow control is required to communicate with some serial devices. Options are:
• None: This option does not toggle or assert control lines.
• DTR: This option asserts the DTR line when the communications port is opened and remains on.
• RTS: This option specifies that the RTS line is high if bytes are available for transmission. After all buffered bytes have been sent, the RTS line is low. This is normally used with RS232/RS485 converter hardware.
• RTS, DTR: This option is a combination of DTR and RTS.
• RTS Always: This option asserts the RTS line when the communication port is opened and remains on.
• RTS Manual: This option asserts the RTS line based on the timing properties entered for RTS Line Control. It is only available when the driver supports manual RTS line control (or when the properties are shared and at least one of the channels belongs to a driver that provides this support). RTS Manual adds an RTS Line Control property with options as follows:
◦ Raise: Specify the amount of time that the RTS line is raised prior to data transmission. The valid range is 0 to 9999 milliseconds. The default is 10 milliseconds.
◦ Drop: Specify the amount of time that the RTS line remains high after data transmission. The valid range is 0 to 9999 milliseconds. The default is 10 milliseconds.
◦ Poll Delay: Specify the amount of time that polling for communications is delayed. The valid range is 0 to 9999. The default is 10 milliseconds.
Tip: When using two-wire RS-485, "echoes" may occur on the communication lines. Since this communication does not support echo suppression, it is recommended that echoes be disabled or a RS-485 converter be used.Operational Behavior
• Report Communication Errors: Enable or disable reporting of low-level communications errors. When enabled, low-level errors are posted to the Event Log as they occur. When disabled, these same errors are not posted even though normal request failures are. The default is Enable.
• Close Idle Connection: Choose to close the connection when there are no longer any tags being referenced by a client on the channel. The default is Enable.
• Idle Time to Close: Specify the amount of time that the server waits once all tags have been removed before closing the COM port. The default is 15 seconds.
Ethernet Settings
Note: Not all serial drivers support Ethernet Encapsulation. If this group does not appear, the functionality is not supported.Ethernet Encapsulation provides communication with serial devices connected to terminal servers on the Ethernet network. A terminal server is essentially a virtual serial port that converts TCP/IP messages on the Ethernet network to serial data. Once the message has been converted, users can connect standard devices that support serial communications to the terminal server. The terminal server's serial port must be properly configured to match the requirements of the serial device to which it is attached. For more information, refer to "Using Ethernet Encapsulation" in the server help.
• Network Adapter: Indicate a network adapter to bind for Ethernet devices in this channel. Choose a network adapter to bind to or allow the OS to select the default.
Specific drivers may display additional Ethernet Encapsulation properties. For more information, refer to Channel Properties — Ethernet Encapsulation.
Specific drivers may display additional Ethernet Encapsulation properties. For more information, refer to Channel Properties — Ethernet Encapsulation.Modem Settings
• Modem : Specify the installed modem to be used for communications.
• Connect Timeout : Specify the amount of time to wait for connections to be established before failing a read or write. The default is 60 seconds.
• Modem Properties: Configure the modem hardware. When clicked, it opens vendor-specific modem properties.
• Auto-Dial : Enables the automatic dialing of entries in the Phonebook. The default is Disable. For more information, refer to "Modem Auto-Dial" in the server help.
• Report Communication Errors: Enable or disable reporting of low-level communications errors. When enabled, low-level errors are posted to the Event Log as they occur. When disabled, these same errors are not posted even though normal request failures are. The default is Enable.
• Close Idle Connection: Choose to close the modem connection when there are no longer any tags being referenced by a client on the channel. The default is Enable.
• Idle Time to Close: Specify the amount of time that the server waits once all tags have been removed before closing the modem connection. The default is 15 seconds.
Operation with no Communications
• Read Processing: Select the action to be taken when an explicit device read is requested. Options include Ignore and Fail. Ignore does nothing; Fail provides the client with an update that indicates failure. The default setting is Ignore.