FEATURES

q CALIBRATION CAPABILITY

q INTEGRAL SENSOR EXCITATION

q OPEN CIRCUIT SENSOR DETECTION

q LOW POWER: 80mW

q INSTRUMENT AMPLIFIER INPUT

q PROGRAMMABLE GAIN

q 12-BIT LINEARITY

q TWO ISOLATED POWER SUPPLIES:

q LOW DRIFT 10V REFERENCE

APPLICATIONS

q UNIVERSAL INPUT CHANNEL FOR

PROCESS CONTROL SYSTEMS

q ISOLATED MEASUREMENT CHANNEL

FOR THERMOCOUPLE, RTD AND

VOLTAGE TRANSDUCERS

q CHANNEL TO CHANNEL ISOLATED

MULTIPLEXED SYSTEMS

q ISOLATED 4 TO 20mA RECEIVER

DESCRIPTION

The ISC300 is an isolated measurement channel with

open circuit sensor detection for use with RTD and

thermocouple temperature sensors. In addition to tem-

perature measurement, the ISC300 can accept full

scale input voltages of

±100mV and ±10V which

allows use with other sensors such as pressure, humid-

ity and flow sensors. The low level resistance mea-

surement capability also allows stimulus and measure-

ment of strain gauges. The measurement channel has

a highly stable internal reference which can be se-

lected from the output side. This allows the user to

calibrate each channel at the factory, record the cali-

bration data and periodically recalibrate the system

while in use over time and ambient temperature

changes.

SELECT

and GAIN

RST

CLK

No Change

1

0

No Change

1

1

Latch

1

^

RESET

0

X

INPUT

SELECT

00

+0.1V

0

1

+10V

1

0

Signal

1

1

GAIN

SELECT

G

0.5

0

50

1

Channel 1 Out

MUX

PGA

Channel 4

A

1

A

0

Channel 3

Channel 2

Ref

0.100V

Com 1

10.0V

99R

R

Current

Reference

20M

Filter

Modulate

Demod

Power

Rectify

Com 1

Com 2

O

P

T

O

C

O

U

P

L

E

L

A

T

C

H

Out

V

CKI

Com 2

V

CLK

G

A

0

A

1

RST

DCom 2

28

25

26

27

18

22

19

20

21

23

24

20M

+V

ISO

–V

ISO

+V

ISO

–V

ISO

Sense 2

+I

P

–I

P

Sense 1

V

REF

I

REF1

I

REF2

Com 1

–V

ISO

2

8

5

6

3

1

4

7

10

9

Barrier

Output Side

Input Side

®

ISC300

International Airport Industrial Park

•

Mailing Address: PO Box 11400

•

Tucson, AZ 85734

•

Street Address: 6730 S. Tucson Blvd.

•

Tucson, AZ 85706

Tel: (520) 746-1111

•

Twx: 910-952-1111

•

Cable: BBRCORP

•

Telex: 066-6491

•

FAX: (520) 889-1510

•

Immediate Product Info: (800) 548-6132

Universal Precision Isolated

MEASUREMENT CHANNEL

PDS-1135A

Printed in U.S.A. October, 1993