Measurement CIO-EXP-GP User Manual

CIO-EXP-GP

g

User’s Manual

Revision 2

January, 2001

© Copyri

ht 2001, Measurement Computing Corporation

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TM

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MEGA-FIFO, the CIO prefix to data acquisition board model numbers, the PCM prefix to data acquisition bo ard
model numbers, PCM-DAS08, PCM-D24C3, PCM-DAC02, PCM-COM422, PCM-COM485, PCM-DMM,
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HM CIO-EXP-GP.lwp

Table of Contents

1 INTRODUCTION
2 SOFTWARE INSTALLATION
3 GENERAL CONFIGURATION

3.1 A/D Board Type Select Jumper

3.2 Setting The Output Channel

3.3 Configuring the A/D Board

3.3.1 DAS08 Family Setup

3.3.2 DAS16 Family Setup

3.3.3 All A/D Boards

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3.4 CONNECTING THE CIO-EXP-GP TO THE A/D BOARD

3.4.1 Connecting to a DAS08 Series A/D Board

3.4.2 Connecting to a DAS16 Series A/D Board

3.4.3 Other A/D Boards

3.5 Powering The CIO-EXP-GP

3.5.1 Power Source Switch

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3.5.2 Powering with the 37-Pin Connector

3.5.3 Powering with the Molex Connector

3.5.4 Powering Through the Power Screw Terminals:

3.6 Daisy-Chaining CIO-EXP-GP Boards

3.7 Connecting a Test Voltage

3.8 Verifying the Installation

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4 CONFIGURATION FOR VOLTAGE MEASUREMENT

4.1 Channel Selection

4.2 Powering the CIO-EXP-GP

4.3 Determining The Appropriate Gain

4.4 Setting the Gain

4.4.1 Setting Board Gain

4.4.2 Setting Channel Gain

4.5 Attenuation

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4.6 Setting the Input Configuration

4.7 Connecting Voltage Signals

4.7.1 Single-Ended Inputs

4.7.2 Floating Differential

4.7.3 Fully Differential

4.8 Verifying the Installation

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5 CONFIGURATION FOR THERMOCOUPLE MEASUREMENT

5.1 Selecting The Output Channel

5.2 Selecting The CJC Output Channel

5.3 Input Configuration

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5.3.1 Setting the Input Configuration

5.3.2 Enabling Open Thermocouple Detection (OTD)

5.3.3 Adding a Ground Reference

5.4 Determining the Appropriate Gain

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5.5 Setting the Gain

5.5.1 Setting the Board Gain

5.5.2 Setting the Channel Gain

5.6 Verifying the Installation

6 CONFIGURATION FOR RTD MEASUREMENTS

6.1 Channel Selection

6.2 VEXC Jumper Select

6.3 CJC Jumper Selection

6.4 Powering the CIO-EXP-GP

6.5 Determining the Appropriate Gain

6.6 Setting the Gain

6.6.1 Setting the Board Gain

6.6.2 Setting the Channel Gain

6.7 Input Configuration

6.7.1 Setting the Input Configuration

6.8 Connecting RTDs To Screw Terminals

6.8.1 Two-Wire RTD Hookup

6.8.2 Three-Wire RTD Hookup

6.8.3 Four-Wire RTD Hookup

6.9 Verifying the Installation

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7 CONFIGURATION FOR RESISTANCE MEASUREMENTS

7.1 Channel Select

7.2 VEXC Jumper Select

7.3 CJC Jumper Select

7.4 Powering the CIO-EXP-GP

7.4.1 Selecting the Power Source for the Board

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7.4.2 Selecting the Power Source for the Excitation Voltage

7.4.3 Selecting the Excitation Voltage

7.5 Determining the Appropriate Gain

7.6 Setting the Gain

7.6.1 Setting the Board Gain

7.6.2 Setting the Channel Gain

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7.7 Setting the Input Configuration

7.8 Configuring the Bridge

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7.8.1 Bridge Completion Resistors

7.8.2 Nulling Potentiometers & Arm Resistor

7.8.3 Strain Gauge Bridge Configuration Examples

7.9 Verifying the Installation
8 SPECIFICATIONS
9 APPENDIX

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9.1 About Strain Gauges

9.1.1 What Are Strain Gauges?

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9.1.2 Specification of Strain Gauges

9.2 Reference Material for Application of Strain Gauges

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1 INTRODUCTION

The CIO-EXP-GP is an eight-channel, signal conditioning accessory designed for use with the DAS08
and DAS16 family of data acquisition boards. It can condition signals from bridge sensors, RTDs or
thermocouples on a per-channel basis. It converts the sensor's output to a voltage suitable for conversion
by a DAS08/DAS16 or other analog to digital conversion board.

This manual is organized into sections that explain the CIO-EXP-GP on a sensor by sensor basis. The
CIO-EXP-GP is complex, and the information on bridge sensors may confuse those interested in RTDs
only, and vice-versa. Here are the sections of this manual:

Software Installation All users should review this section regardless of the

application.

General Configuration: All users should review this section regardless of the

application.

Configuration for Voltage Measurement: Users interested in voltage measurement applications

should review this section.

Configuration for Thermocouples Users interested in temperature measurement

applications using thermocouples should review this
section.

Configuration for RTD Measurement Users interested in temperature measurement

applications using RTDs should review this section.

Configuration for Resistance Measurement: Users interested in resistance or strain gauge

measurement applications should review this section.

Please carefully read the installation and general configuration sections, and each of the sections
pertaining to the sensors you intend to use. There are optional resistors, jumpers, switches, and other
connections to be made on the CIO-EXP-GP. Failure to set up the channels correctly for the sensor in
use will result in inaccurate or invalid measurements.

2 SOFTWARE INSTALLATION

Software is not included with the CIO-EXP-GP, but each of the data acquisition boards with which it is
intended to be used includes software called InstaCal™ that may be used to aid installation, verify
operation and perform calibration of the CIO-EXP-GP. The disk or CD labeled InstaCal contains this
software package. If you ordered the Universal Library™, you should load InstaCal from that CD or
disk set.

The board has a variety of switches and jumpers to set before installing the board in your computer.
InstaCal will show you all available options, how to configure the various switches and jumpers to match
your application requirements, and will create a configuration file that your application software (and the
Universal Library) will refer to so the software you use will automatically have access to the exact
configuration of the board.

Please refer to the Software Installation Manual regarding the installation and operation of InstaCal. Use
InstaCal along with the following hard copy information to set the hardware configuration of the board.

1

3 GENERAL CONFIGURATION

3.1 A/D Board Type Select Jumper

The CIO-EXP-GP can be used with either DAS08 or DAS16 family boards because the signal
assignments of the 37-pin connectors match those of the DAS08 and may be adapted to those of the
DAS16 with a C-EXP2DAS16-10 cable. Select the A/D board type via the JB10 jumper.

Jumper JB10 on the ,CIO-EXP-GP located near the 37-pin connector, selects the
A/D board family as DAS08 or DAS16.

Figure 3-1 shows the jumper set to use the CIO-EXP-GP with a CIO-DAS08
family board.

'$6

DAS Family Select

3.2 Setting The Output Channel

Jumpers labeled “CH SEL” located near the 37-pin connector select the A/D board channel that the
output from the active sensor will be connected to.

'$6

Figure 3-1

37-Pin

CONNECTORS

37
36
35
34
33
32
31
30
18
17
16
15
14
13
12
11

9
8
7

P1 & P2

MUX ADDR 3
MUX ADDR 2

MUX ADDR 1

OUTPUT CHA NNEL
SELECT JUMPER

0
1
2
3
4
5
6
7
8

9
10
11
12
13
14
15

AMP

GAIN

1 OR 2.5

INPUT 0
INPUT 1

INPUT 2

INPUT 3

INPUT 4

INPUT 5

8-CHANNEL MULT I P LE XER

INPUT 6

INPUT 7

Figure 3-2. Output Channel Select Jumper

2

There are three groups of 16-position jumpers. One jumper group determines the signal output channel,
one jumper group determines the excitation voltage output channel and one determines the Cold Junction
Compensation (CJC) output channel. Signal output is always used, CJC output is used only with
thermocouples and excitation output may be used with bridge sensors.

There are 16 jumper locations for each function. Each corresponds to one of the 16 pins on the 37 pin
connector. When the CIO-EXP-GP is connected to a DAS08, only the first 8 channels (labeled 0-7) can
be used. When the CIO-EXP-GP is connected to a DAS16, all 16 jumper positions can be used. In each
case, the jumper corresponds to a channel number on the A/D board.

If the jumper setting does not agree with the selection made in InstaCal setup, InstaCal and the Universal
Library will not be able to make readings from the CIO-EXP-GP. Figure 3-3 is a diagram of the Channel
Select jumper. There are two other groups of output jumpers similar to this group.

The top group (shown here) is marked CH SEL

1234567

0

8 9 10 1112 14 15

13

(Channel Select), the center jumper group is
VEXC SEL (excitation voltage select) and the
bottom group is marked CJC SEL (Cold Junction
Compensation Select).

CH SEL

CHANNEL 0 SELECTED
FOR SENSOR OUTPUT

Figure 3-3. Output Channel Select Jumper

Place the jumper on the pin which corresponds to the A/D board's input channel. Each jumper set must
select a unique A/D channel. For example, if you are using the excitation or CJC outputs in addition to
the signal output, each should be set to a different channel number.

One individual channel must be selected for each bank of 8 EXP channels. For example, if you are using
several CIO-EXP-GP boards, the jumper setting for each board must be unique. If you select channel 0
for the first board, do not use this channel for any of the other boards.

3.3 Configuring the A/D Board

3.3.1 DAS08 Family Setup

The input mode of the A/D board must be single-ended to be compatible with the CIO-EXP outputs.
Some of the boards in the DAS08 series have differential inputs that can be converted to single-ended
inputs. See the information shipped with your A/D board for conversion to single-ended inputs.

3.3.2 DAS16 Family Setup

The input mode of the A/D board must be single-ended to be compatible with the CIO-EXP outputs.
Most of the DAS16 series is switch selectable for either 8 differential or 16 single ended inputs. When
used with the CIO-EXP, set the switch to 16 channel, single-ended mode.

3.3.3 All A/D Boards

If you are using an A/D board with switch - selectable ranges, consider the application and determine the
best fit for range vs. expected voltage. For example, when measuring resistance such that the output of
the EXP board is expected to be in the range of 3 to 4.5 Volts, a unipolar 5V range would be the best
choice.

3

If the range on your A/D board is fully programmable, the software you use for measurement will
determine the range.

3.4 CONNECTING THE CIO-EXP-GP TO THE A/D BOARD

3.4.1 Connecting to a DAS08 Series A/D Board

A CIO-DAS08 series board may be connected directly through a C37FF series cable from the P1
connector on the CIO-EXP-GP to the A/D analog connector. The JB10 jumper should be left in the
DAS08 position as set at the factory.

3.4.2 Connecting to a DAS16 Series A/D Board

Connection to a DAS16 series board requires a special 37-conductor cable (CEXP2DAS16-10) since pin
relationship of CIO-EXP and DAS16 signals is not 1:1.

Install the CEXP2DAS16-10 cable connector labeled “MUX” into the P1 connector of the CIO-EXP-GP
board and the other end into the DAS16 series board’s analog connector.

3.4.3 Other A/D Boards

For other boards, use the connector diagram in
Figure 3-4 to construct a cable, or call us and
discuss the possibility of a custom
manufactured cable.

The signals from the CIO-EXP-GP are
voltages from each channel and an analog
ground. There should be no voltage between
the analog ground and the power ground.

The MUX address lines control the setting of
the channel multiplexer. When all are low, the
mux is set to channel 0. The lines are binary
coded. MUXADDR1 is the LSB and
MUXADDR3 is the MSB.

A jumper (CH SEL) selects which output
channel is read by the DAS08 or DAS16
board.

DAS16 LLGND

OUTPUT 8 / LLGND

OUTPUT 9
OUTPUT 10
OUTPUT 11
OUTPUT 12
OUTPUT 13
OUTPUT 14
OUTPUT 15

SHUNT CALIBRATION

MUX ADDR 3
MUX ADDR 2
MUX ADDR 1

NC
NC
NC
NC
NC

NC

19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1

37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20

OUTPUT 0
OUTPUT 1
OUTPUT 2
OUTPUT 3
OUTPUT 4
OUTPUT 5
OUTPUT 6
OUTPUT 7
+5 VOLTS FROM PC
POWER GROUND
NC
NC
NC
NC
NC
NC
NC
NC

Figure 3-4. 37-Pin Connectors

4

3.5 Powering The CIO-EXP-GP

The CIO-EXP-GP can be powered through the 37-pin cable, the power screw terminal or the Molex
connector. The power that can be carried through the 37-pin connector is limited so we recommend
using this source only when a single CIO-EXP-GP is used.

The power required to run a CIO-EXP-GP is dependent on the board configuration. Remember that
additional power will be drawn when the CIO-EXP-GP is configured for resistance measurement (bridge
configuration) due to the current required for each bridge.

3.5.1 Power Source Switch

One of the switches on the eight-position DIP switch (S17) near
the output channel jumpers controls the source of the +5 volts
power to the board. Shown in Figure 3-5 it is the 3rd switch
from the left.

When positioned down, (ON, +5 COMP), the +5V power is
drawn from the personal computer through the signal cable.

When positioned up (OFF, REM) , +5V power is taken from
the optional external 5V power connector (the Molex connector
labeled P19) or the +5V screw terminal connection.

REM

X1

S17

0.5V

1V

2V

10V

4V

+5 COMP

X2.5

GND

Figure 3-5. Power Source Switch

3.5.2 Powering with the 37-Pin Connector

You can power the CIO-EXP-GP via the 37-pin cable. No more than one CIO-EXP-GP should be
powered using the 37-pin cable.

This option is not available when using some A/D boards. If the A/D board you are using supplies +5V
at pin 29 (or at pin 1 when using the C-EXP2DAS16 signal cable), you can power the CIO-EXP-GP
through the 37 pin connector by setting the power select switch on S17 to “+5 COMP”.

3.5.3 Powering with the Molex Connector

The CIO-EXP-GP can be powered off the PC's power supply by connecting the optional external 5V
power connector (the Molex connector labeled P19) to the PC’s power supply through a C-MOLEX-10
cable. This cable has the same Molex connector that is used inside the PC and so can be connected
directly to the PC's power supply through one of the spare connectors. The cable is keyed, so it should
not be forced. When inserted properly it will slide easily and snap in place.

3.5.4 Powering Through the Power Screw Terminals:

A set of screw terminals labeled “+5V REM” and “REM GND” are located below the 37-pin connectors
P1 and P2. You can power the CIO-EXP-GP from a +5V (±5%) power supply capable of at least 400
mA. For this option, set the power select switch on S17 to “REM”.

CAUTION:

Connect the ground of the power supply to the ground of the personal computer with a

heavy gauge wire. If you do not strap the two grounds together, a voltage between these grounds will

5

affect measurements. If the potential exceeds the protection range of the input circuits, the board may be

SENSE

(
)

C

S
NS

damaged.
At this time, ignore the other screw terminals located next to the power and ground terminals. They are

needed only with certain sensors and will be explained in those sections.

3.6 Daisy-Chaining CIO-EXP-GP Boards

Connect one CIO-EXP-GP to another using a C37FF-# ribbon cable. Connect from P2 on the ‘upstream’
board to P1 on the ‘downstream’ board. Make sure each of the boards in the chain have a unique channel
selected (CH SEL jumper is set to a different number on each board).

3.7 Connecting a Test Voltage

Make your initial test of the CIO-EXP-GP with a voltage
signal of between -5 and 5V. If you use an AC signal
source, keep the frequency below 70Hz to avoid
attenuation by the CIO-EXP-GP’s low pass filter.

Each input circuit has eight screw terminals associated
with it. These terminals are shown in the diagram to the
right.

To connect a voltage signal to the input circuit you use
three screw terminals as follows:

+SENSE Connect to + voltage

−

SENSE Jumper to −P

−

P Connect to Ground

There is not enough room on the board for the full name
next to each terminal so the eight screw terminals
associated with each input circuit are labeled on the
CIO-EXP-GP as follows:

+P Excitation voltage

−

SENSE Low side of input

−

SENSE Hardwired to the other −SENSE, same function

−

IEXC Excitation current return

−

P Excitation voltage return, common with −IEXC
+SENSE High side of input
+SENSE Hardwired to other +SENSE, same function
+IEXC Excitation current

SHORTING WIRE

−

+P EXCITATION. VOLTS

+P

VOLTS IN OR COMMON

−

−

E
E

−

EXCITATION CURRENT

INSTALLED

−

IEX

+ VOLTS IN

+ VOLTS IN

−

P

+ SENSE

+ SENSE

CH0

Figure 3-6. Input Screw Terminals

+EXCITATION CURRENT

(+)IEXC

The use of the terminals is dependent on the type of sensor you have connected to the input circuit, and
the nomenclature on the terminals has been chosen to make the most sense for bridge and RTD sensors.
For voltage and thermocouple sensors the names on the terminals are not typical. Please refer to the
section on the measurement you are making in order to learn how to use the terminals.

6

3.8 Verifying the Installation

For verification of the installation, leave any switches or jumpers not mentioned above in their default
positions. Each of the gain switches (CH0 through CH7 and S17-7) should be off (toward the upper edge
of the board) for a gain of X1 (unity gain). The channel configuration switches (labeled “IN CONFIG”
should be left in the default position (the switches labeled “4” in the ON position and those labeled “3”
in the OFF position - the label is printed on the board, not the switch).

To verify the installation, use the InstaCal program installed on your computer. This software came with
your A/D board if you bought the board from the same manufacturer as the CIO-EXP-GP. If your A/D
board is not from the same manufacturer but is compatible, please call technical support and request a
copy of InstaCal.

Use InstaCal's TEST option to verify that a signal present at one of the CIO-EXP-GP inputs can be read.
You will not need to set any jumpers other than those previously mentioned, and should not set any
switches or install any passive components until you have verified the installation.

When using an AC signal source, keep the frequency below 70Hz to avoid attenuation by the low pass
filter.

7

4 CONFIGURATION FOR VOLTAGE MEASUREMENT

The CIO-EXP-GP is an amplification, signal conditioning and multiplexing accessory for DAS boards.
The inputs are suitable for connecting a low frequency voltage to the DAS board so it can be measured.
The CIO-EXP-GP is a one-of-eight multiplexer which means that for every channel in your DAS board,
you can multiplex eight different signals to it. You can expand the number of inputs of your DAS board
by eight for every CIO-EXP-GP board, up to the number of inputs on the DAS board. For example, a
DAS08 has 8 inputs. Eight times eight is sixty four. Using CIO-EXP-GP boards you can bring 64 inputs
into the PC with one DAS08 in one slot.

It is unlikely that you purchase a CIO-EXP-GP to measure voltages. The CIO-EXP-GP has a 70Hz low
pass filter and quite a bit of elaborate circuitry designed for bridges, TCs, and RTD sensors. For
applications requiring only voltage measurements, a CIO-EXP16 or CIO-EXP32 would be less expensive
and do the same job.

Possibly you have one or two voltages to measure in addition to bridge or RTD sensors and would like to
connect those signals to the CIO-EXP-GP.

4.1 Channel Selection

The General Configuration section describes the channel selection, setting the jumper and verifying the
installation and operation of the CIO-EXP-GP with your data acquisition board. Configure your boards
as described in that section before continuing with this section.

4.2 Powering the CIO-EXP-GP

The General Configuration section describes the power selection options, setting the power select switch
and verifying the installation and operation of the CIO-EXP-GP with your data acquisition board.
Configure your boards as described in that section before continuing with this section.

4.3 Determining The Appropriate Gain

To accurately measure a voltage, the full scale of the signal should be matched to the full range of the
input circuit. (Most DAS boards have an input range of ±5V, which is the native range of the analog to
digital converter at the heart of the board. Some DAS boards include amplification on the input circuit to
allow the signal to be amplified to make better use of the resolution of the A/D.) For example, an input
signal which varies between 0 and 1 volt would only be using 1/10th of a ±5V A/D converter's
resolution. By switching the input signal of the DAS board to unipolar (no negative voltage) and
amplifying the input signal by 5, the entire range of the A/D converter is used and a higher resolution
measurement may be made. By adding this gain and selecting this range, the resolution on a 12-bit A/D
improves from 2.4 millivolts per bit to 0.24 millivolts per bit. If you needed to measure a change of 1
millivolt, you would need an amplification of 10.

In order to match your signals with the input range of the A/D board, you should do a similar calculation
and set switches on the CIO-EXP-GP for the required gain. Remember to make sure that the settings in
InstaCal match the switches on the DAS and CIO-EXP-GP boards.

If you are measuring signals greater than the maximum full scale range of the A/D, see the section on
attenuation.

8

To choose a switch-selectable amplification, here are the calculations you need to perform:
Divide the full range selected for the A/D board by the full range of the signal to be measured to

determine the maximum gain of the CIO-EXP board. For best resolution, use the highest gain possible
up to the calculated maximum gain.

For example, if the A/D board is to be used at a range of ±5V, the full range of the board is 10. If your
signal ranges between -0.5 volts and 0.5 volts, the full range of the signal is 1 volt. Divide 10 by 1 for a
result of 10. That is the maximum gain you can use.

If your signal is unipolar and ranges less than 0 to 5V, you would likely choose the 5V unipolar range for
the A/D board (if available). Given an input signal ranging from 0 to 0.5 volts, the full range of the
signal is 1/2 volt. Divide 5 (the full range of the A/D) by 0.5 (the full range of the signal for a result of

10. That is the maximum gain you can use.

4.4 Setting the Gain

Gain (amplification) allows you to boost your signal to take full advantage of the resolution of the A/D
converter. However, when amplifying a signal, any noise is amplified as well.

Amplification for ALL channels (board output gain) is switch selectable (S17) for X1 or X2.5.
Input amplification for EACH CHANNEL is switch selectable (GAIN switches CH0 through CH7) for

X1, X10, X100 or X1000. A user-specified gain may be set by supplying a precision resistor at position
RX### and setting the “U” option on the CH ## GAIN switch to ON.

4.4.1 Setting Board Gain

There is a switch on DIP switch block S17
labeled X1 and X2.5. Sliding this switch down
amplifies the output of the multiplexers by 2.5.
The factory default position (up) has a gain of 1
(unity). Refer to Figure 4-1.

The X2.5 gain switch is useful in some voltage
and bridge measurements. If you desire a
voltage gain of 2.5, 25, 250 or 2500, set this
switch down.

Figure 4-1. Board Output Gain Switch Location
For voltage measurements, a gain of 2500 is very high and will reduce your signal to noise ratio.
The effect of this switch is multiplicative with respect to the individual channel gains. For example, if

you have set an input channel gain to X100 and the board output gain to X2.5, the signal is amplified by
250 before it reaches the A/D board.

GND

X1

X2.5

REM

S17

0.5V

1V

2V

4V

+5 COMP

10V

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4.4.2 Setting Channel Gain

Select a gain (higher than unity) by moving the switch for
that gain down. All other switches should be left in the
UP position.

.

A custom gain may be selected on the CIO-EXP-GP by
installing a precision resistor and setting the switch
marked “U” (User) in the down position. See Table 4-1
following for board positions and some sample gain
values.

Figure 4-2. Input Channel Gain Select Switches

Table 4-1. Resistor Positions for User-Selected Gains

CH4

U

X10

CH0

Resistor PositionChannelResistor PositionChannel

X100

N
O

X1000

GAIN FOR CHANNELS 0 and 4
SET FOR A GAIN OF 10.
SLIDER DOWN SELECTS GAIN
ALL OTHERS TO BE OFF (UP)

N
O

RX1044RX1000
RX1055RX1011
RX1066RX1022
RX1077RX1033

Resistor ValueGain

776 Ohms50
364 Ohms100
161 Ohms200

40 Ohms500
17 Ohms700
10 Ohms800

The equation for selecting the USER gain resistor is:

= [40000 / (Gain − 1)] − 40

R

USER

Amplifying a signal on one channel will not affect the reading on another channel.

4.5 Attenuation

If your signal is in a range greater than the full scale range of the A/D, you must either set the A/D for a
higher full scale range (if available) or divide (attenuate) the signal until the result is less than or equal to
the A/D’s full scale range. This section describes signal attenuation.

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