OPTO 22 AC34
Single Channel, Isolated RS-485 Serial Port

@6C67.ADF AC34 Single Channel, Isolated RS-485 Serial Port

195.2 AC34 Single Channel, Isolated RS-485 Serial Port User's Manual

The AC32 and AC34 -DO- support the PB16HQ Quad I/O modules.


AC34 Isolated RS-422/485 Adapter For Micro Channel Computers

Note: You MUST use twisted pair to be immune to crosstalk and electrical noise!

Note: Use a four pair cable when using the additional CTS and RTS handshaking lines.


Serial Port Pinout


Jumper Blocks B and C Schematic

Jumper Blocks B and C Settings

POSN Group B Description
1 Pull up xmit line
2 Terminate xmit line
3 Pull down xmit line
4 Terminate rcv line
5 Pull down rcv line
6 Pull up rcv line
7 RTS control RS-422/485
8 Not used
POSN Group C Description
1 Pull up xmit line
2 Terminate xmit line
3 Pull down xmit line
4 Terminate rcv line
5 Pull down rcv line
6 Pull up rcv line
7 CTS control RS-422/485
8 Not used

Jumpers B2 and B4 connects 220 ohm terminating resistors from + to - on the transmitter (To OPTOMUX) and receiver (From OPTOMUX), respectively. Install both of these jumpers in a normal OPTOMUX network.

Jumpers C2 and C4 connects 220 ohm terminating resistors from + to - on the RTS and CTS lines, Install both of these jumpers in a normal OPTOMUX network.

Note: If multiple host computers are used, Jumpers B2 and B4 should only be installed on the AC34 channel which are physically at the end of the serial network cables.

Enable RS-422/485 (PC UART RTS) (Jumper B7)
Jumper B7 controls the enabling of the RS422/RS485 driver.  Removing the jumper will always enable the driver.  Installing the jumper will allow the RTS output on the UART to control the driver. The driver is enabled when RTS is active and disabled when RTS is inactive.

If Jumper B7 is installed, then also install Jumpers B1 and B3.  These jumpers passively pull the transmit lines (To OPTOMUX) to the inactive state.

If the AC34 is operating with a multidrop OPTOMUX network, then also install Jumpers B5 and B6. These jumpers passively pull the receive lines (From OPTOMUX) to the inactive state. Jumpers C5 and C6 must also be installed to passively pull the CTS line to the inactive state.

Enable RS-422/485 (RS-422 CTS) (Jumper C7)
Jumper C7 controls the enabling of the RS422/RS485 driver.  The driver is under control of the CTS input with the jumper installed. Jumpers B7 and C7 must never be installed at the same time. The CTS Disable Jumper disables the CTS line on the adapter card.  The factory setting is with the jumper installed. Remove the jumper only if CTS is required.

Warning! Jumpers B7 and C7 must never be installed at the same time.

AC-34 Default Jumper Configuration

Shaded jumpers are installed.


Description

The AC34 is an isolated RS-422/485 adapter card (transient protected) which can drive up to 100 devices on a multidrop network, and features bi-directional handshake lines for RTS and CTS. It can be configured for operation as COM1 through COM8 and offers full hardware and software compatibility with IBM PS/2 Models 50, 60, 70, 80, and compatible computers. The AC34 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.

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Last update: 23 May 2022 - Changes & Credits | Legal Info & Contact