Documentation Number 232OPSDA1397 - pg. 1/3

Not Recommended for New Installations.

Please contact Technical Support for more information.

This product designed and manufactured in USA of domestic and imported parts by

Optically Isolated Serial Data Acquisition Module

Model 232OPSDA

Description

The 232OPSDA is an optically isolated RS-232 serial port data acquisition module with a variety of I/O inputs. The six

A/D input channels provide 12-bit resolution and have the following configuration: one 4-20mA current loop input, two 0 to
5V buffered inputs, one 0 to 10V input, and two 0 to 5V non-buffered inputs. These A/D channel configurations can be
modified, if required. In addition, the 232OPSDA contains one digital input and one digital output. Demonstration software
and a data logging utility are included with the 232OPSDA module.

Features

2500V Optical Isolation protection between RS-232

and

I/O side of module

one 4-20mA input channel (input resistance = 10

)

two 0 to 5V buffered A/D input channels

(input resistance = 1T

)

one 0 to 10V A/D input channel (input resistance = 200K

)

two 0 to 5V non-buffered A/D input channels

one digital input and one digital output line

Automatic baud rate detection (1,200 to 9,600 baud)

Commands

Only three commands are needed to control the 232OPSDA: the read A/D command, the read digital I/O command,

and the set digital output command. The command string consists of four or five bytes: the "!" character, the address byte
"0" character, two command characters, and a data byte (if required).

232OPSDA Commands

Function Command

Response

Read A/D Channels !0RA{#}

{ch#msb}{ch#lsb}{ch(#-1)msb}....{ch0msb}{ch0lsb}

Read Digital I/O

!0RD

{I/O states}

Set Digital Output

!0SO{#}

no response

NOTE:{...} represents one byte

In addition to the commands mentioned above, an extended set of commands can be used to provide bit-error

identification. With these extended commands, the "#" character is used in place of the "!" character, and the compliment
of the data byte must be sent after the data byte. The extended commands are shown below.

232OPSDA Extended Commands

Function Command

Response

Read A/D Channels #0RA{#}~{#}

{ch#msb}~{ch#msb}{ch#lsb}~{ch#lsb}{ch(#-1)msb} ~{ch(#-
1)msb}{ch0msb}~{ch0msb}{ch0lsb}~{ch0lsb}

Read Digital I/O

#0RD

{I/O states}~{I/O states}

Set Digital Output

#0SO{#}~{#}

no response

NOTE: Each ~{...} represents the complement of one byte.

Documentation Number 232OPSDA1397 - pg. 2/3

Not Recommended for New Installations.

Please contact Technical Support for more information.

This product designed and manufactured in USA of domestic and imported parts by

A/D Converter

The 232OPSDA has six channels of 12-bit A/D. These channels have several different input configurations to handle

a variety of applications. One channel converts a 4-20mA analog input current to a voltage. Two channels can read
voltages between 0 to 5V and are buffered to provide a high input impedance. One channel can read voltages between 0
and 10V, and two non-buffered channels can read voltages between 0 and 5V.

Digital I/O Lines

The 232OPSDA has one digital input that is CMOS/TTL compatible and can handle voltages from -30VDC to +30VDC.

One CMOS/TTL compatible digital output is also available on the 232OPSDA. These two digital lines are available on
terminal blocks.

Terminal Block Assignments

Terminal Block

Function

Description

TB 0

A/D 0

Current Loop A/D Input*

TB 1

A/D 1

0 to 5V Buffered A/D Input**

TB 2

A/D 2

0 to 5V Buffered A/D Input

TB 3

A/D 3

0 to 10V A/D Input

TB 4

A/D 4

0 to 5V Non-buffered A/D Input

TB 5

A/D 5

0 to 5V Non-buffered A/D Input

TB 6

DOUT

Digital Output

TB 7

DIN

Digital Input

GND GND

Isolated

Ground

+12VDC

Power Supply Connection

The current loop input uses a non-inverting amplifier with a gain of 23.064. Spaces for through-hole

resistors are provided to change the gain of this non-inverting amplifier (Gain must be

1). By decreasing

the gain, currents up to 100mA can be read using A/D 0.
**This 0-5V input uses a voltage follower circuit. Space is provided for through-hole resistors to change
the voltage follower into a non-inverting amplifier with a gain > 1. This allows you to read small voltages
with greater accuracy.

Power Supply

The 232OPSDA is port powered on the RS-232 side of the device, and an external isolated power supply (232PS2 or

equivalent) is needed to power the I/O side of the device. The GND wire is connected to the terminal block labeled GND,
and the positive voltage wire is connected to the terminal block labeled +12VDC.

Communications

The 232OPSDA connects to the host computer's RS-232 serial port using a DB-25 (female) connector. The module

automatically detects baud rates from 1,200 to 9,600. A data format of 8 data bits, 1 stop bit, and no parity is used. The
RS-232 side of the device is port powered. Power is drawn from RTS and DTR regardless of the state of each. If none of
these lines are available, a +12VDC supply can be connected to pin 25 of the DB-25 connector.

RS-232 Connector Pinout

DB-25 Pin #

Function

2 TD
3 RD
4 RTS
5 CTS
6 DSR
7 GND
8 CD

12 GND
20 DTR
25

Optional Power Connection

Documentation Number 232OPSDA1397 - pg. 3/3

Not Recommended for New Installations.

Please contact Technical Support for more information.

This product designed and manufactured in USA of domestic and imported parts by

Specifications

Analog to Digital Converter

Resolution: 12

bit

Channels:

A/D Connections:

Terminal Blocks

4-20mA Input Channel:

Input Resistance:

Input

Offset

Voltage:

1500

Input Offset Drift Voltage:

0.5

Maximum Signal Conditioning Error:

3% of output

0 to 5V buffered Input Channels:

Input

Resistance:

Input

Offset

Voltage:

1500

Input Offset Drift Voltage:

0.5

Maximum Signal Conditioning Error:

1% of output

0 to 10V Input Channel:

Input

Resistance:

200K

Input

Offset

Voltage:

1500

Input Offset Drift Voltage:

0.5

Maximum Signal Conditioning Error:

1% of output

0 to 5V Non-buffered Channels:

Input

Offset

Voltage:

1500

Input Offset Drift Voltage:

0.5

Total

Unadjusted

Error:

1.75LSB

Non-buffered A/D input channels must be driven from a source impedance less than 1K

Digital Input

Voltage Range:

-30VDC to 30VDC

Low Voltage:

-30VDC to 1.0VDC

High Voltage:

2.0VDC to 30VDC

Leakage Current:

1 microamp max.

Connection:

Terminal

Block

Digital Output

Low Voltage:

0.6VDC @ 8.7mA

High Voltage:

4.3V @ -5.4mA

Connection:

Terminal

Block

Power Supply

Input Voltage:

9VDC to 16VDC @10mA (Doesn't include the power consumption of external devices.)

Connection:

Terminal

Blocks

Communications

Standard: RS-232

Baud Rate:

1,200 to 9,600 (automatic detection)

Format:

8 data bits, 1 stop bit, no parity

Port Power:

RTS and DTR

Isolation

Protection:

2500V

Connector:

DB-25S

(female)

NOTE: Both port power and an isolated external power supply are needed to power the 232OPSDA!

Part Number 232OPSDA