OPTO 22 AC34
 Single Channel, Isolated RS-485 Serial Port
 
@6C67.ADF - AC34 Single Channel, Isolated RS-485 Serial Port

OPTO22 AC32 Option  ver 2.02 ADFs for AC32, AC33, AC34, 
      LCTRM137.EXE [LCTERM] dumb terminal program (plus other programs)
      OS120.EXE [OPTOSCAN] finds all OPTOMUX stations

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

LCTERM Version 1.35 -  Simple terminal program that communicates with LC4 and LC2.

os.exe   OptoScan R.131 DOS
oswin.zip OptoScan Windows 16-bit
oswin32.zip OptoScan Windows 32-bit

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

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


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.

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

 

POSN

Group C Description

1

Pull up xmit line

 

1

Pull up xmit line

2

Terminate xmit line

 

2

Terminate xmit line

3

Pull down xmit line

 

3

Pull down xmit line

4

Terminate rcv line

 

4

Terminate rcv line

5

Pull down rcv line

 

5

Pull down rcv line

6

Pull up rcv line

 

6

Pull up rcv line

7

RTS control RS-422/485

 

7

CTS control RS-422/485

8

Not used

 

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.

Connecting Wire
    This is the wiring between the D shell connector and the first OPTOMUX on the link.

Please note that the pin numbers are labeled on the connector.



Communicating With OPTOMUX

 

            Before applying power to OPTOMUX Brain Board(s), set the baud rate and command protocol on the OPTOMUX Brain Board(s).  The baud rate and command protocol are selected by the B group of jumpers on the OPTOMUX Brain Board(s). (Please refer to the OPTOMUX B1 and B2 Digital and Analog Brain Boards Operations Manual, Form 203 for additional information.)

 

For the checkout, remove all of the group B jumpers from one OPTOMUX Brain Board and disconnect all other OPTOMUX Brain Boards on the network. This will select a baud rate of 300, the four-pass protocol, and an OPTOMUX address of 255.

 

Connect the D shell connector to the AC34 card and turn on the power to the IBM PS/2 and the OPTOMUX.  To test the link, enter the IBM BASIC interpreter and type in the following program. The underlined part of line ten must be changed to COM1 when using the AC34 card as communications port one.

 

10        OPEN "COM2:300,N,8,1,RS,CS,CD,DS" AS #1

20        PRINT #1,°>FFACD"

30        INPUT #1,B$

40        PRINT B$

 

When running the program, both the receive and transmit LED's on the OPTOMUX will flash. The IBM PS/2 will display the AFFACD on the screen. If nothing is displayed, verify that all the wiring has been done correctly.