Instrument Installation and Wiring

NOTE: If you cannot establish communications between SpecView and your instruments first check your instrument's manual for correct wiring instructions. For further assistance please contact the instrument manufacturer.  Many have test programs that will check your converter and connections.

RS232

Most computers have built in standard RS232 (9-pin) ports specified as:

Pins

Code

Description

Input/Output

1

DCD

Data carrier detect

Input

2

RXD

Receive data

Input

3

TXD

Transmit data

Output

4

DTR

Data terminal ready

Output

5

GRND

Ground

N/A

6

DSR

Data set ready

Input

7

RTS

Request to send

Output

8

CTS

Clear to send

Input

9

RI

Ring indicator

Input

If the intention is to use RS232 wiring to connect the instrument, then the wiring and the connection to the instrument will be specified by the instrument's manufacturer.

RS232 is point-to-point, therefore it has a maximum of a single instrument connection.

RS422 & RS485

If the intention is to use RS422 or RS485 wiring to connect the instrument, then an external converter from RS232 to either RS422 or RS485 (as appropriate) must be used. SpecView recommends (and can supply) converters made by B&B Electronics.

The reason the B&B device is recommended is because it has "Automatic Send Data Control", this automatically switches from transmit to receive and so works very well with SpecView.


Please note that RS422/485 connections should be terminated correctly, please see the instrument manufacturer's instructions.

NOTE: We strongly caution against using internal 422/485 cards

Unless you are expert in testing and troubleshooting communications we recommend using internal RS232 ports and external isolated converters. Since all computers have 232 ports a second computer can be used to determine whether a problem is in the computer or wiring if an external converter has been used.

·Each serial port MUST operate with its own interrupt unless special interrupt sharing cards and software are used.
·Serial ports using 16550 UARTS or above are strongly recommended, especially if BAUD rates above 9600 are going to be used. They are required for instruments that use block mode data reading.

The number of controllers that can be connected to SpecView is only limited by the available addresses on the controllers.  Most instruments go to 99 addresses and SpecView supports up to 40 ports.

RS422 and RS485 would need repeaters if there are more than 16 or 32 instruments respectively. Please see the instrument manufacturer's instructions or the converter's manual.
 

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(C) 2017 SpecView Corp & SpecView Ltd.  Page Updated: 11 April 2017

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