AC7 OPTO 22, AC7 Datasheet - Page 25

• Manufacturer Part Number: AC7
• Description: Computers, Interface Cards
• Manufacturer: OPTO 22

Specifications of AC7

• Peak Reflow Compatible (260 C): No
• Leaded Process Compatible: No
• Features: RS232 To RS422 Converter
• Interface: RS-422⁄485
• Module Type: Adapter Card
• Mounting Type: Protective Enclosure
• Voltage, Supply: 115 VAC ± 10 VAC @ 50⁄60 Hz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

General guidelines for using an AC7A/B with other RS-422/485 devices:
a. The RS-422/485 screw terminals on the AC7A/B are labeled TO+, TO-, FO+, and FO- . This labeling
b. The RTS and CTS terminals are used for hardware handshaking (flow control). RTS± are outputs from the
c. The AC7A/B was designed to communicate in 4-wire RS-422/485 mode. In the 4-wire mode uses two
d. In most applications, the AC7A/B can also be used in 2-wire RS-485 mode. In the 2-wire mode uses one
convention is for Opto 22’s Optomux I/O. For use with devices other than Opto 22’s Optomux I/O,
the following convention applies to the RS-485 port of the AC7A/B
AC7A/B. CTS± are inputs into the AC7A/B.
twisted-pairs of wiring (four conductors total) are used for communication. In 4-wire mode, one twisted-
pair of wires is used for the transmit signal and the other twisted pair of wires is used for the receive
signal. 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.
twisted-pair of wiring (two conductors total) is used for communication. In 2-wire mode, the same twisted-
pair of wires is used for the transmit signal and the receive signal. One additional pair (pair #2) of wires is
used to connect the LOGIC GND of the AC7A/B to the COM terminal of the RS-485 device. To use the
AC7A/B in two wire mode, see the section titled Two-Wire RS-485 Mode (page 25).
Figure 3-14: RS-422/485 Cabling Diagram (alternative, less noise immune)
TO+ = Transmit+
TO- = Transmit-
FO+ = Receive+
FO- = Receive-
AC7A/B User’s Guide 25
INSTALLATION (cont.)