Siemens SG-6048-01 manual Connecting with Dial-Up Modems, Modem Isolated Multi-Drop Converter

3 Installing the Converter

3.5Connecting with Dial-Up Modems

If the distance between your PC and Isolated Multi-Drop converter is greater than 3.5 miles, you can connect them using dial-up modems. To install the Isolated Multi-Drop converter using dial-up modems, you need these items:

•two dial-up modems

•one RS-232 serial cable no more than 50 feet in length (unless your PC’s modem is directly installed in the computer)

•one null modem cable no more than 50 feet in length

•a telephone line for each modem

•one Isolated Multi-Drop converter mounting kit (if you want to mount the converter to the switchgear panel)

If you are mounting the Isolated Multi-Drop converter to a switchgear panel, do that first. (Refer to Appendix B for mounting dimensions.)

Follow these steps, while referring to Figure 3.4.

1		1
2		2	Pins 2 and 3
3		3	Transposed
4	*	4
5		5
6		6
7		7
8		8
	*		Not required
20		20	*with converter

To	To
Modem	Isolated
	Multi-Drop
	Converter

1.Connect one dial-up modem to your PC; use RS-232 serial cable unless your modem is installed directly in the computer. (If you need help in connecting the modems and setting their switches, refer to the modem’s manual.)

2.Using a null modem cable, connect one dial-up modem to the RS-232 port on the converter according to

Figure 3.5.

3.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.)

Figure 3.5 Pin Assignments for Null Modem Cable

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 the connector on the RS-485 cable.)

5.Plug one end of the converter’s power cord into the 120 VAC connection 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.

Modem

IMPORTANT

Use a null modem cable

between the Isolated Multi-Drop Converter and the modem.

Modem

Port 4

Port 3

22 AWG Shielded Twisted-Pair Cable

4000 Ft. Maximum

+

SHLD

-

RS-485

+

SHLDBus

-

+

+Device

-#1

+Device

-#n

RS-232 Cable

50 Ft. Maximum

PC

with

Supervisory

Null Modem Cable

50 Ft. Maximum

Port 2

Port 1

SHLD	Up to 32 devices
-

+To Other

SHLD

- RS-485 Devices

Software

Isolated Multi-Drop

Converter

Figure 3.4 Connecting the Converter with Dial-Up Modems

Siemens Energy & Automation, Inc. 7