Siemens SG-6048-01 manual Connecting Directly to a PC

3 Installing the Converter

3.3Connecting Directly to a PC

To connect the Isolated Multi-Drop converter directly to a PC, you need an RS-232 serial cable of not more than 50 feet in length. Make sure the cable is a DCE-DTE cable, not a null modem cable. The following table lists the minimum set of required signals and the pin assignments for DB-25 to DB-25 and DB-9 to DB-25 cable connectors:

Table 3.1 RS-232 Pin Assignments

Pin Number
on Connector	Signal Name
2	TxD
3	RxD
4	RTS
7	GND
8	DCD

4.Insert the RS-485 connector(s) into the port(s) on the front of the converter. (Refer to section 3.1 for instructions on installing a connector on the RS-485 cable.)

5.Connect the supplied power cord to the 120 VAC connector on the converter, and plug the other end into any 120 VAC grounded power source.

6.Turn the converter’s power switch on, and verify that the PWR LED is lit. (Refer to Section 5 “Troubleshooting” if the PWR LED is not lit.)

7.Start your software.

To connect the converter to a PC, follow these steps while refering to Figure 3.3 below:

1.Connect the plug end of an RS-232 serial cable to the RS-232 port on the Isolated Multi-Drop converter.

2.Connect the socket end of the serial cable to an RS-232 port on your computer.

3.If you are using application software that requires direct DCD/RTS control, set the DCD/RTS switch to RTS and the MAN/AUTO switch to MAN. If you are using application software that does not require the direct DCD/RTS control, set the MAN/AUTO switch to AUTO, and use the BAUD thumbwheel to set the data rate to match that of the application software and the ACCESS devices on the network. (In automatic mode, the converter ignores the setting of the DCD/RTS switch.)

				+	Device
			22 AWG Shielded	-	#1
			Twisted-Pair Cable
		+	4000 Ft. Maximum
	Port 4	SHLD
		-
		+	RS-485
			Bus
	Port 3	SHLD		+	Device
		-
				-	#n
		+		Up to 32 devices
	Port 2	SHLD
		-
	RS-232 Cable
	50 Ft. Maximum		To Other
		+
	Port 1	SHLD
PC			RS-485
		-
with			Devices
Supervisory	Isolated Multi-Drop
Software
	Converter

Figure 3.2 Connecting the Converter Directly to a PC

Siemens Energy & Automation, Inc. 5