Modicon Driver Tag Type Properties: Serial Tab
The Serial tab for the Modicon driver tag properties folder consists of attributes used to identify and establish a connection to the Modicon I/O device.
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Indicates the station address of the Modicon programmable logic controller. By default, the PLC Address field is set to 1.
An expression may be used to provide the address if needed. This may be required on a network where the address varies depending on the workstation where the tag is running.
Note that, to create a valid expression for an address that contains non-numeric characters, you must enclose the address in quotation marks. e.g. “31.0.0.0” See: Modbus Plus PLC Addressing.
Allows you to set the receiver time-out limit in seconds or fractions of a second. This is the length of time that this driver should wait for a reply from the PLC or RTU.
Enables you to select the serial port tag or TCP/IP tag you wish to be associated with this driver tag. A serial port tag opens a serial port to enable communications between VTS and your PLC or RTU. A TCP/IP tag enables you to connect to a series of hosts, allowing you to transmit data across a network or over the Internet.
The Port field can be cleared using the X button that appears to its right.
Sets the amount of time (in seconds or in fractions of a second) to wait before clearing noise. Enabled only when Squelch Noise Present has been selected on the Options tab.
The Retries spin box enables you to select the number of attempts that will be made by this driver if there is no reply to a message. An error will be declared after this number has been reached.
The Hold checkbox indicates whether this driver should hold data from the PLC or RTU in the event of a communications failure.
If the Hold checkbox is selected, the last received value from the PLC or RTU will be held.
If the Hold checkbox is not selected, the data will be invalidated in the event of a communications error.
By default, the Hold checkbox is not selected.
The Retry Delay field enables you to specify the amount of time (in seconds or fractions of a second) that the driver will wait between attempts to repeat a transmission of data if the previous attempt(s) have failed.
By default, the Retry Delay field is set to 0 (indicating that there should be no delay between retry attempts).
The RTS Key Off Delay field represents the amount of time (in seconds) that this Modicon driver will wait before dropping RTS at the end of a data transmission.