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AC7A/B USER'S GUIDE
Form 0233-160920—September 2016
43044 Business Park Drive
Temecula
CA 92590-3614
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•
Phone: 800-321-OPTO (6786) or 951-695-3000
Fax: 800-832-OPTO (6786) or 951-695-2712
www.opto22.com
Product Support Services
800-TEK-OPTO (835-6786) or 951-695-3080
Fax: 951-695-3017
Email: support@opto22.com
Web: support.opto22.com
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Table of Contents
Summary of Contents for OPTO 22 AC7A
- Page 1 AC7A/B USER’S GUIDE Form 0233-160920—September 2016 43044 Business Park Drive Temecula CA 92590-3614 • • Phone: 800-321-OPTO (6786) or 951-695-3000 Fax: 800-832-OPTO (6786) or 951-695-2712 www.opto22.com Product Support Services 800-TEK-OPTO (835-6786) or 951-695-3080 Fax: 951-695-3017 Email: support@opto22.com Web: support.opto22.com...
- Page 2 Specifications are subject to change without notice. Opto 22 warrants all of its products to be free from defects in material or workmanship for 30 months from the manufacturing date code. This warranty is limited to the original cost of the unit only and does not cover installation, labor, or any other contingent costs.
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Page 3: Table Of Contents
Features .............................. 5 Specifications ........................... 6 Dimensions ............................6 Installing the AC7A/B for use with Opto 22’s Optomux I/O ....7 Equipment Required for Installation ..................7 Mounting the AC7A/B ........................7 Connecting AC Power to the AC7A/B ..................8 Connecting the AC7A/B to Your PC .................. - Page 4 WELCOME Additional Technical Information ............27 General Notes ..........................27 Two-Wire RS-485 Mode ......................28 Using Multiple AC7A/B Units on One Link ................30 Background ........................... 30 Description ..........................30 Setup ............................31 Biasing ............................31 Termination ..........................31 Wiring and Related Jumpers ..................... 31 Additional Jumpers ......................
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Page 5: Welcome
The converter operates as a full duplex device with transmission speeds up to 38,400 baud for distances up to 5,000 feet using two twisted pairs and a ground wire. Only “REV L” boards and above (AC7A) and “Rev C” boards and above (AC7B), can be used up to 115,200 baud. -
Page 6: Introduction
The AC7A/B has optical isolation between its RS-232 port and its RS-422/485 port, with full transient protection on the RS-422/485 lines. The AC7A/B is an open chassis circuit board, and is designed to be mounted inside a protective enclosure (protective enclosure not included.) The converter operates as a full duplex device with transmission speeds up to 38,400 baud for distances up to 5,000 feet using two twisted pairs and a signal ground wire. -
Page 7: Specifications
RS-422/485 full duplex over two twisted pairs and a signal ground. Additional twisted pairs for RTS and CTS. Also supports RS-485 2-wire mode. This requires user to build a custom RS-232 cable. Indicators Transmit, receive, RTS, CTS, and power. DIMENSIONS Figure 1-2: AC7A/B Card Dimensions 6 AC7A/B User’s Guide... -
Page 8: Installing The Ac7A/B For Use With Opto 22'S Optomux I/O
If you are using the AC7A/B card to communicate with equipment other than Opto 22’s Optomux I/O, please see “Installing the AC7A/B for use with devices other than Opto 22’s Optomux I/O” later in this document. If you would like more detailed information, please see “Additional Technical Information”. -
Page 9: Connecting Ac Power To The Ac7A/B
The AC7A/B has a terminal strip with three screw terminals for AC power. The AC power, which is supplied to the AC7A/B, should have three wires, two for AC power and one for earth ground (usually colored green). Connect the wire for earth ground (usually colored green) to the center screw terminal which is labeled GND. -
Page 10: Connecting The Ac7A/B To Your Pc
A standard RS-232 serial cable may be used to connect the AC7A/B adapter card to the PC. One end of the RS-232 cable must have a male 25-pin (DB-25) connector for the AC7A/B. The other end of the cable is for the PC, and will most likely need either a 9-pin (DB-9) female connector, or a 25-pin (DB-25) female connector, depending on your computer. - Page 11 Figure 2-6: 9-Pin to 25-Pin, 3-Wire RS-232 Cable (made by user) Note: Some serial cables that look like standard straight-through cables are actually null modem cables. The wiring diagram for a NULL modem cable is shown below: 10 AC7A/B User’s Guide...
- Page 12 2 on one end of the cable and pin 3 on the other end. These two pins are tied together on a standard 25-pin to 9-pin straight-through cable. In a 25-pin to 9-pin null-modem cable, pin 2 of one end is tied to pin 2 of the other end. AC7A/B User’s Guide 11...
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Page 13: Setting The Ac7A/B Rs-232 Jumpers (First Group - Near The 25-Pin Rs-232 Connector)
(FIRST GROUP - NEAR THE 25-PIN RS-232 CONNECTOR) This group of jumpers is located right next to the DB-25 connector on the AC7A/B. The first 6 pins of the group are labeled PIN 2 OUT , PIN 3 IN , and PIN 2 IN , PIN 3 OUT . The rest are labeled by the letters A through H. -
Page 14: Setting The Ac7A/B Rs-422/485 Jumpers (Groups B And C)
These two jumper groups are located above the green 9-screw-terminal RS-422/485 connector. Group B is on the left, and group C is on the right. If the AC7A/B is being used in a standard Optomux network in either repeat or multidrop mode, install the jumpers as shown below. -
Page 15: Connecting The Ac7A/B To The Optomux Network
100 ohms and a capacitance of 12.5 pF/ft. The first pair of twisted wire connects the TO+ and TO- terminals on the AC7A/B to the FH+ and FH- terminals on the Optomux device (TO+ to FH+ and TO- to FH-). The second pair of twisted wire connects the FO+ and FO- terminals on the AC7A/B to the TH+ and TH- terminals on the Optomux equipment. -
Page 16: Apply Ac Power
The AC7A/B should now be ready to use with your Optomux network. After all wiring connections are made, and jumper settings have been checked, it is time to supply AC power to the AC7A/B. The AC7A requires 115 VAC at 50–60 Hz. -
Page 17: Installing The Ac7A/B For Use With Devices Other Than Opto 22'S Optomux I/O
The AC7A/B was originally designed specifically to make it easy to connect any device with a standard RS-232 port to Opto 22’s Optomux I/O in 4 wire RS-422/485 mode. However, the AC7A/B can also be used as a general purpose, bi-directional RS-232 to RS-422/485 converter. -
Page 18: Connecting Ac Power To The Ac7A/B
The AC7A/B has a terminal strip with three screw terminals for AC power. The AC power that is supplied to the AC7A/B should have three wires, two for AC power and one for earth ground (usually colored green). Connect the wire for earth ground to the center screw terminal which is labeled GND. -
Page 19: Connecting The Ac7A/B To A Pc Or Other Rs-232 Device
A standard RS-232 serial cable may be used to connect the AC7A/B adapter card to the PC. One end of the RS-232 cable must have a male 25-pin (DB-25) connector for the AC7A/B. The other end of the cable is for the PC, and will most likely need either a 9-pin (DB-9) female connector, or a 25-pin (DB-25) female connector, depending on your computer. - Page 20 INSTALLATION (cont.) This section applies only to the 25-pin [DB25] RS-232 connection on the AC7A/B adapter card. Figure 3-5: 25-Pin to 25-Pin, 3-Wire RS-232 Cable (made by user) Figure 3-6: 9-Pin to 25-Pin, 3-Wire RS-232 Cable (made by user) Note: Some serial cables that look like standard straight through cables are actually null modem cables.
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Page 21: Setting The Ac7A/B Rs-232 Jumpers (First Group - Near The 25-Pin Rs-232 Connector)
Moving the jumpers to the opposite position causes pin 2 on the AC7A/B RS-232 port to receive data, and pin 3 on the AC7A/B RS-232 port to transmit data. The jumpers may need to be moved to the other position, depending on whether or not you are using a standard straight-through cable, or a null modem cable. - Page 22 Figure 3-9: Jumper Settings for Standard Straight-Through RS-232 Cable If you are using a NULL modem cable to connect the AC7A/B to your PC, you will need different jumper settings. The jumper settings for a NULL modem cable connecting an AC7A/B to a PC (a DTE RS-232 port) are shown below: Figure 3-10: Jumper Settings for use with an RS-232 Null Modem Cable More detailed information about these jumpers is available in “Additional Technical Information”.
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Page 23: Rs-232 Handshaking Signals For Hardware Flow Control
RS-422/485 device does: Install jumpers A, B, F, and H on the AC7A/B, and make sure the RTS ± and CTS ± lines are connected between the AC7A and the RS-422/485 device. Remove jumpers C, D, E, and G on the AC7A/B. -
Page 24: Setting The Ac7A/B Rs-422/485 Jumpers (Groups B And C)
RS-422/485 devices require hardware flow control: Install jumpers E and G on the AC7A/B, and make sure the RTS ± and CTS ± lines are connected between the AC7A and the RS-422/485 device. Remove jumpers A, B, C, D, F, and H on the AC7A/B. This should work, although your particular equipment may require different settings. -
Page 25: Connecting The Ac7A/B To An Rs-422/485 Device
The first pair of wires is used for the transmit line. The second pair of wires is used for the receive line. The third pair of wires is used to connect the LOGIC GND of the AC7A/B to the COM terminal of the RS-485 device. Finally, the shield of the three pairs of twisted wire should be tied to earth ground at only one end of the shield. - Page 26 One additional pair (pair #3) of wires is used to connect the LOGIC GND of the AC7A/B to the COM terminal of the RS-422/485 device.
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Page 27: Applying Ac Power
The AC7A/B should now be ready to use. After all wiring connections are made, and jumper settings have been checked, it is time to supply AC power to the AC7A/B. The AC7A requires 115 VAC at 50-60 Hz. The AC7B uses 220VAC at 50–60 Hz. -
Page 28: Additional Technical Information
(i.e., data is entering the RS-232 port and exiting the RS-422/485 port). TX = RS-232 —> AC7A/B —> RS-422/485 The RX (Receive) LED will flash when the AC7A/B is receiving data into its RS-422/485 port (i.e., data is entering the RS-485 port and exiting the RS-232 port). -
Page 29: Two-Wire Rs-485 Mode
A few minor modifications must be made if you are using the AC7A/B in 2-wire mode. First, you will probably have to make your own custom RS-232 cable from the AC7A/B to the PC. This is to ensure that DTR (pin 20) on the AC7A/B’s RS-232 connector is not connected. If you are using a 25-pin port on the PC, then you’ll need to make these three connections:... - Page 30 ADDITIONAL TECHNICAL INFORMATION Second, install the three sets of jumpers on the AC7A/B as shown below. The shaded areas indicate where jumpers need to be placed. Figure 4-3: Three Sets of AC7A/B Jumpers Finally, connect FO+ to TO+, and FO- to TO- on the AC7A/B as shown below.
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Page 31: Using Multiple Ac7A/B Units On One Link
AC7A/Bs in the system, there will be multiple transmitters connected on the RS-422 portion of some or all of the AC7A/B’s. In order for this to work, each AC7A/B must be configured so that the RS-422 portion is setup in RS-485 mode. -
Page 32: Setup
AC7A/Bs. Additional Jumpers In addition, since the RTS and CTS pairs are not used on the RS-422/485 side of the AC7A/B, it is best to install jumpers C2, C4, C5, and C6 to prevent spurious LED activity. -
Page 33: Commonly Used Rs-232 Signals
COMMONLY USED RS-232 SIGNALS It is possible to effectively rewire certain pins of the RS-232 connector on the AC7A/B with the group of jumpers labeled A through H. These pins carry hardware handshaking signals which are commonly used to coordinate communication flow. -
Page 34: Using Protective Ground On Ac7A/B
Terminating resistors are needed at the two ends of this main line. Usually, this is done at the devices located at the physical ends of the line. Since the AC7A/B is usually located at the beginning or end of an RS-485 transmission line, the AC7A/B is usually the location for one of the termination resistors. -
Page 35: Communication Jumpers
However, only one pair of biasing resistors may be placed on an RS-485 network. Jumpers are provided on the AC7A/B to connect the biasing resistors to the RS-485 communication lines. If biasing is already accomplished at some other point on the RS-485 line, then the biasing resistor jumpers should be removed on the AC7A/B. -
Page 36: Troubleshooting
RS-232 baud rate to make the LEDs flash slower, which will make the LEDs easier to see. If the TX LED is flashing, this means that RS-232 data is being received by the AC7A/B and re-transmitted out the RS-422/485 transmit (TO±) terminals. -
Page 37: Glossary Of Terms
TD – an abbreviation for Transmit Data. Also sometimes shown as TX or TXD. This is the pin on a serial communication port where data is sent out to other devices. 36 AC7A/B User’s Guide... -
Page 38: Rs-422/485 Cable Specifications
Belden P/N 8102 (with overall shield) • Belden P/N 9729 (individually shielded) • Belden P/N 8162 (individually shielded with overall shield) • Manhattan P/N M3475 (individually shielded with overall shield) • Manhattan P/N M39249 (individually shielded with overall shield) AC7A/B User’s Guide 37... -
Page 39: Appendix A: Ac7A/B Db9 (J2) Connection Pinout
APPENDIX A APPENDIX A Figure A-1: AC7A/B DB9 (J2) Connection Pinout 38 AC7A/B User’s Guide... -
Page 40: Product Support
PRODUCT SUPPORT PRODUCT SUPPORT If you have any questions about this product, contact Opto 22 Product Support Monday through Friday, 8 a.m. to 5 p.m. Pacific Time. Phone: 800-TEK-OPTO (835-6786) 951-695-3080 Fax: 951-695-3017 E-mail: support@opto22.com Opto 22 Web site: http://www.opto22.com... - Page 41 Opto 22 • 43044 Business Park Drive • Temecula, CA 92590-3614 • Phone: (951) 695-3000 • (800) 321-OPTO • Fax: (951) 695-3095 • www.opto22.com Inside Sales: (800) 321-OPTO • Product Support: (800) TEK-OPTO • (951) 695-3080 • Fax: (951) 695-3017 • Email: sales@opto22.com • Form 1335-050601...
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