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Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM User Manual

Page 317

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Publication AG-UM008C-EN-P - February 2005

Configuring RSLinx Classic Software for DF1 Half-Duplex Communications 9-11

Figure 9.10 Slave Port Configuration

Table 9.10 Port Configuration Parameter Descriptions

Control

Control Text

COM Port

Select the serial port of the device with which the polling slave driver will communicate. The default is
COM1.

Baud Rate

Select the baud rate of the device with which the polling slave driver will communicate. The default is
19200.

Stop Bits

Select the Stop Bits (1, 1.5 or 2). The default is 1.

Data Bits

Select the Data Bits (7 or 8). The default is 8.

Parity

Select the parity of the device with which the polling slave driver will communicate. The default is None.

Use RTS Line

In Windows NT only, if enabled, RTS is turned on when the polling slave driver is about to begin a
transmission, and turned off when the transmission is complete. This behavior may change based on the
Hardware Handshaking timer values. If cleared, RTS is asserted (turned on) when the port is opened, and
remains asserted until the driver is terminated. The default is unchecked.

Delay before asserting RTS
(ms)

This is useful when using half-duplex modems that require an off-delay timer to control the carrier wave.
When the driver receives characters, it may assert the RTS line to begin its own transmissions before the
sending slave has the opportunity to deassert the RTS line. This provides a minimum time delay between
when the driver determines it needs to transmit something, and the time it actually asserts the RTS line.
The default is 0.

Delay after RTS asserted &
before Xmit (ms)

Some modems require a period of time after the RTS line is asserted for the carrier wave to stabilize. The
character transmission is delayed for the period of time specified. These values may be expressed in
milliseconds, but RSLinx Classic actually rounds the value down to the nearest 10 ms. The default is 50 ms.

Delay after Xmit before
de-asserting RTS (ms)

Some modems require an off-delay after the last character is transmitted out the serial port before the RTS
line is deasserted. These values may be expressed in milliseconds, but RSLinx Classic actually rounds the
value down to the nearest 10 ms. The default is 0.

Use CTS Line

If enabled, characters will not be transmitted out the serial port unless the CTS line is asserted. Not
currently implemented.