Omega Products PCI-DAS1200 Installation Manual

User's Guide

http://www.omega.com

e-mail: [e-mail]

PCI-DAS1200

Table of Contents

1.0 INTRODUCTION

2.0 INSTALLATION

2.1 WINDOWS .......................................................

2.2 DOS .............................................................

3.0 HARDWARE CONNECTIONS

3.1 CONNECTOR PIN DIAGRAM .......................................

3.2 CONNECTING SIGNALS TO THE PCI-DAS1200 .......................

4.0 ANALOG CONNECTIONS

4.1 ANALOG INPUTS ..................................................

4.2 WIRING CONFIGURATIONS ......................................

................................................

..................................................

...................................

........................................

1

3
3

32.1.1 Install the InstaCALTM software ...................................

32.1.2 Launching InstaCALTM ..........................................

42.1.3 Using InstaCalTM ...............................................

42.1.4 Testing the Installation ...........................................

5

52.2.1 Install the InstaCalTM software ....................................

52.2.2 Launching InstaCALTM ..........................................

52.2.3 Using InstaCalTM ...............................................

62.2.4 TESTING THE INSTALLATION ...................................

6
7
7

8
8

84.1.1 Single-Ended and Differential Inputs ................................

104.1.2 System Grounds and Isolation .....................................

12

134.2.2 Common Ground / Differential Inputs ...............................

144.2.3 Common Mode Voltage < +/-10V / Single-Ended Inputs .............

144.2.4 Common Mode Voltage < +/-10V / Differential Inputs .............

154.2.6 Isolated Grounds / Single-Ended Inputs .............................

154.2.7 Isolated Grounds / Differential Inputs ...............................

5.0 PROGRAMMING & APPLICATIONS

5.1 PROGRAMMING LANGUAGES ....................................

5.2 PACKAGED APPLICATIONS PROGRAMS ..........................

6.0 SELF-CALIBRATION OF THE PCI-DAS1200

6.1 CALIBRATION CONFIGURATION .................................

7.0 PCI-DAS1200 REGISTER DESCRIPTION

7.1 REGISTER OVERVIEW ...........................................

7.2 BADR0 ..........................................................

7.3 BADR1 ..........................................................

...........................

...................

.......................

16
16
16

17
17

19
19
19
19

197.3.1 INTERRUPT / ADC FIFO REGISTER ..............................

217.3.2 ADC CHANNEL MUX AND CONTROL REGISTER ...................

237.3.3 TRIGGER CONTROL/STATUS REGISTER ..........................

Table of Contents

7.3.5 DAC CONTROL/STATUS REGISTER (Does not apply to

PCI-DAS1200/JR) ..................................................

7.4 BADR2 ..........................................................

7.5 BADR3 ..........................................................

7.6 BADR4 ..........................................................

257.3.4 CALIBRATION REGISTER ......................................

26
27

277.4.1 ADC DATA REGISTER ..........................................

277.4.2 ADC FIFO CLEAR REGISTER ....................................

28

287.5.1 ADC PACER CLOCK DATA AND CONTROL REGISTERS .............

297.5.2 DIGITAL I/O DATA AND CONTROL REGISTERS ...................

33

337.6.1 DAC0 DATA REGISTER .........................................

337.6.2 DAC1 DATA REGISTER .........................................

8.0 ELECTRICAL SPECIFICATIONS

ANALOG INPUT SECTION ............................................

ANALOG OUTPUT: ..................................................

PARALLEL DIGITAL INPUT / OUTPUT ................................

COUNTER SECTION .................................................

OTHER SPECIFICATIONS: ...........................................

...............................

34
34
35
35
36
37

1.0 INTRODUCTION

The PCI-DAS1200 and PCI-DAS1200/JR are multifunction measurement and control boards designed to operate in
computers with PCI bus accessory slots. The difference between the boards is that the analog ouput functions are not
supported by the /JR board. The architecture of the boards is loosely based on the original CIO-DAS16; the standard
of ISA bus data acquisition. M uch has changed though, and all of it due to improvements in technolo gy. Surface
mount packaging technology and custom ASICS allow a far greater range of control over programmable options,
such as calibration, triggering, synchronization, and data transfer.

Even the connector has changed. New, denser connectors allow up to 100 signal lines where 37 was once the
standard.

The PCI-DAS1200 and PCI-DAS1200/JR are completely plug-and-play. There are no switches or jumpers on the
board. All board addresses are set by your computer’s plug-and-play software.

These products are supported by our Universal Library programming library. As an owner, you are entitled to the
latest revision of the manual and software. Just cal l with your current revision numbers handy, and request an update
be sent to you.

Gain and Offset Autocal

12-Bit, 10uS

DAC0

DAC

Data

Control

12-Bit, 10uS

DAC1

VDAC 0

VDAC 1

Burst/Scan

Analog In
16 CH S.E.
8 CH DIFF.

Gain and Offset Autocal

Mux

&

Gain

Gains = 1, 2, 4, 8

12-Bit, 33 0KHz

Start EOC

1024 x 12

FIFO

INT

PA (7:0)

PB (7:0)

PC (7:0)

ADC

Pacer

CTR 2
CTR 1

Sample

Counter

CTR0

Digital I/O

Port A

Port B

Port C

INT

Control

Control

8

Scan

ADC

Pacer

Burst

Control

Logic

Trigger
Control

Decode/Status

Bus

Timing

PCI

CONTROLLER

Burst/Scan

CONTROLLER

&

Interrup t

EXT PCR

XTRIG

Boot

EEPROM

10 MHz

PCI BUS (5 V, 3 2 -BIT, 33 MH Z )

FPGA

DAC

Control

Int
Ctl

BADR1
BADR2
BADR3
BADR4

CLK2

CTR2

GATE2

OUT2
CLK1

CTR1

GATE1

OUT1

ADC

INT

XTRIG

INT

Time Base

10MHz

Index

Counter

User

CTR 0

Control

GATE
CLK
OUT

LOCAL BU S

3&,'$6

%ORFN 'LDJUDP

1

Gain and Offset Autocal

Burst/Scan

Analog In
16 CH S.E.
8 CH DIFF.

PA (7:0)

PB (7:0)

PC (7:0)

Mux

&

Gain

Gains = 1, 2, 4, 8

ADC

Pacer

CTR 2
CTR 1

Control

Sample

Counter

CTR0

INT

Digital I/O

Port A

Port B

Control

Port C

12-Bit, 330KHz

Start EOC

8

Boot

EEPROM

1024 x 12

FIFO

ADC

Pacer

Control

Trigger
Control

Decode/Status

Bus

Timing

PCI

CONTROLLER

Burst/Scan

CONTROLLER

Scan

&
Burst
Logic

BADR1

BADR2

BADR3

BADR4

Interrupt

EXT PCR

10 MHz

XTRIG

PC I BU S (5 V, 32-BIT, 33MH Z )

INT

FPGA

Int
Ctl

INT

Time Base

LOCAL B US

GATE2

GATE1

XTRIG

10MHz

CLK2
OUT2

CLK1

OUT1

INT

Index

Counter

CTR 0

3&,'$6-5

%ORFN'LDJUDP

CTR2

CTR1

ADC

User

Control

GATE
CLK
OUT

2

2.0 INSTALLATION

The PCI-DAS1200 and PCI-DAS1200/JR boards are easy to use. This quick start procedure will help you setup,
install, and test your board quickly and easily. We assume you already know how to open the PC and install expan­sion boards. If you are unfamiliar or uncomfortable with board installation, please refer to your computer’s
documentation.

2.1 WINDOWS 95, 98 & NT

PCI products are completely plug and play. Simply follow the steps shown below to install your PCI hardware.

1.

Turn your computer off, unplug it, open it up, and insert the PCI board into any available PCI slot.

2.

Close your computer up, plug it back in, and turn it on.

3.

Windows 95, 98 will automatically detect the board as it starts up. If the board 's installation file is already
on the system, it will load without user interaction. If the installation file is not detected, you will be
prompted to insert the disk containing it. The required file is on the InstaCal disk or CD you received with
your board. The appropriate file will then be automatically loaded , and the PCI board will appear in the
Device Manager under DAS Components.

2.1.1 Install the InstaCAL™ software

InstaCal is a powerful installation, calibration, and self-test program included with all boards. It is
very important that you load and run InstaCal prior to trying to use your board. To install InstaCal, insert the Insta-
Cal disk or CD into an appropriate disk drive in your computer. From the main
left of your screen) select
For example if the InstaCal floppy disk is in your “a” drive, from the RUN screen enter

Alternatively, from the RUN screen, select browse, select the drive where the InstaCal disk or CD resides, then
select

setup.exe

sure the InstaCal floppy disk or CD is in its drive and press

The install wizard will now launch, and you will then be prompted for additional information. Follow the instruc­tions and, if possible, accept the defaults. If this is your first installation, we urge you to accept the defaults. It will
be easier for us to assist you in the unlikely event of trouble during your system setup and operation.

The installation routines will create all required folders/directories and unpack the various pieces of compressed
software. The default location is on your main hard drive in a directory or folder named C:\CB\).

If you have purchased the Universal Library programmers library (highly recommended with the PCI-DAS1602
series), the installation program will install all the software required to run the PCI board as well as the Universal
Library.

and click OK. The

. At this point type the drive letter where the InstaCal disk resides followed by

un

R

Add/Remove Programs

utility found in the Control Panel can also be used. Be

Install…

.

menu (located on the lower

Start

a:\setup

. (omit the period.)

:\setup

2.1.2 Launching InstaCal

Prior to starting InstaCal, reboot your computer so the various changes made to your startup files are active.

.

Use the InstaCal shortcut if you opted to install it.

From Win95, use "Start: Run", type

Alternatively, you may use Windows Explorer to find inscal.exe. It should be on your main hard drive in a directory
called C:\CB. (if C:\ is your main hard drive). To launch InstaCal, simply double-click on the file

32 at the prompt, and click OK.

inscal

inscal .exe

.

3

2.1.3 Using InstaCal

InstaCal is the Installation, Calibration and Test software supplied with all I/O boards.

If InstaCal finds that a new PCI board has been installed and is not in the configuration file (cb.cfg) a dialog will
appear listing any PCI boards that InstaCal has detected in the system. Each board in the list may
be checked or unchecked. Those boards in the list that are checked will be added to the configuration file and appear
in the InstaCal’s board list view.

InstaCal help is available by pressing the F1 function key. Most of InstaCal is intuitively obvious, and for that
reason there is no user's manual for InstaCal.

The base address and IRQ are allocated by the PC’s PCI plug & play software, and may not be modified through
InstaCal. If you have installed ISA bus boards in the past, you are familiar with the need to select a base address and
interrupt level. On PCI systems this is not of concern to you. The operating system and installation software
automatically selects the base address and IRQ, and ensures that it does not conflict with other installed boards.

Additional board options that are automatically set, may be configured by selecting the Board Configuration menu in
InstaCal This option will display the available board configuration parameters as well as the address and IRQ
already assigned to the board. All board information is stored in the configuration file CB.CFG. This file is accessed
by the Universal Library for programmers. Note also that the Universal Library is the I/O board interface for
packaged applications such as Labtech Notebook and HP-VEE, therefore the InstaCal settings must be made in order
for these and other applications to run.

The board's base address is also stored in the system software. Once InstaCal installation software is run, other
programming methods such as direct IN and OUT statements can write and read the PCI board registers by reference
to the base address and the offset from base address corresponding to the chart of registers located elsewhere in this
manual.

But a word of warning is in order here. Direct writes to the addresses simply by reference to the base address of the
PCI board I/O registers is not advised. Since the addresses assigned by the PCI plug & play software are not under
your control, there is no way to guarantee that your program will run in any other computer. Not only that, when you
install new systems or components in your computer, previous base address assignments may be changed, and any
particular board may be moved. It is best to use a library such as Universal Library or a program such as HP-VEE to

make measurements with your PCI board.

2.1.4 Testing the Installation

After you have run the install program and set your base address with InstaCal, it is time to test the installation. The
following section describes the InstaCal procedure to test that your board is properly installed.

With InstaCal running, choose the TEST item on the main menu.

a.

Select the board you just installed from InstaCal’s board list view.

b.

Select the option Test/Analog to perform a board loop back test. This test will exercise the various functions
of the board by simply connecting one of the board’s output signals to one of the board’s input channels.

c.

Select an input channel and signal source to test.

d.

Complete the connections shown in the dialog box and verify that the indicated waveform is displayed in
the plot window.

e.

The “I/O Test Menu” lists the option “Plot”, select it and make the connections as shown to test your card.

4

2.2 DOS AND/OR WINDOWS 3.X

Most users are now installing b oards on systems with Windows 95 or higher o perating systems. However, if you
wish to install your PCI boar d in a machine running Wind ows 3.1 and/o r DOS your BIOS will automa tically detect
the board on boot-up. In this case please proceed to the following section titled “InstaCAL”

Note: InstaCal and Universal Library support for the PCI-DAS1200/JR is not currently available in DOS or
Windows 3.x. If you are going to be using the /JR board with DOS or Windows 3.1, call Technical Support for
assistance.

2.2.1 Install the InstaCal software

Insta

Cal installs the same way for Windows 3.x as it does for Windows 95. (i.e., setup.exe). See paragraph 2.1.1. If

you are running DOS, call Technical suppport for special sequences.

2.2.2 Launching InstaCal

Prior to starting

Insta

Cal, reboot your computer so the various changes made to your startup files are active.

From the DOS prompt you may start

From Windows 3.x, use the file ma nager to find
called C:\CB. (if C:\ is your main hard drive). To launch
(You may also launch

Insta

Cal via the FILE menu, select

Insta

CAL by simply typing:

instacal.exe

RUN

instacal

. It should be on your main hard drive in a directory

Insta

CAL, simply double click on the file

, type

and hitting enter.

instacal

and click on OK.)

Instacal.exe

2.2.3 Using InstaCal

Insta

Cal is the Installation, Calibration and Test software supplied with all I/O boards. If you have

yes

Insta

.

Cal displays is:

Insta

Cal will do the rest of

a PCI board installed in a PCI slot in your computer, the first message

INSTACAL: PCI Card Detection

Card PCI-DAS1200 found in slot # N

Do you wish to add this board to the configuration file?

A dialog box “Add PCI Card?” also appears. You should choose

Two additional dialog boxes will open. One shows the boards currently installed in your configuration file, the
second allows you to choose a board number to assign to the PCI board. If this is your first installation simply hit
enter to accept the default of BOARD 0.

If you have other boards alr eady installed, choose a board number not curr ently in use.
the initial installation of your PCI board selecting addresses and other system resource settings which are not your
choice to select. In PCI systems, these settings are assigned by the plug & play system software.

.

Insta

Cal help is available by pressing the F1 function key. Most of

there is no user's manual for

The base address is allocated by the PCI plug & play procedure and may not be modified. If you have installed ISA
bus boards in the past you are familiar with the need to select a base address and interrupt level. On PCI systems this
is not of concern to you. It is not up to you to select a base address and ensure that it does not conflict with an
installed port. In PCI systems, the operating software and installation software do the selection and checking for
you.

The program
information is stored in the configuration file CB.CFG. This file is accessed by the Universal Library for program­mers. Note also that the Universal Library is the I/O board interface for packaged applications such as Labtech
Notebook and HP-VEE, therefore the

Insta

Cal selects and sets the base address from the range of available addresses. The address and other

Insta

Cal.

Insta

Cal settings must be made in order for these and other applications to run.

Insta

Cal is intuitively obvious and for that reason

5

The board's base address is also stored in the system software. Once InstaCal installation software is run, other
programming methods such as direct IN and OUT statements can write and read the PCI board registers by reference
to the base address and the offset from base address corresponding to the chart of registers located elsewhere in this
manual.

But a word of warning is in order here. Direct writes to the addresses simply by reference to the base address of the
PCI board I/O registers is not advised. Since the addresses assigned by the PCI plug & play software are not under
your control, there is no way to guarantee that your program will run in any other computer. Not only that, if you
install another PCI board in your computer after the orginal PCI board’s addresses have been assigned, those
addresses may be moved by the plug & play software when the second board is installed. It is best to use a library

such as Universal Library or a program such as HP-VEE to make measurements with your PCI board.

2.2.4 TESTING THE INSTALLATION

After you have run the install program and set your base address with InstaCal, it is time to test the installation. The
following section describes the InstaCal procedure to test that your board is properly installed.

With InstaCal running, choose the TEST item on the main menu.

a.

Select the board you just installed

b.

If the choice “Internal Test” is available, then select Internal Test. If not, proceed to e. below.

c.

The internal control registers of the board will then be tested. If this test is successful, your board is
installed correctly.

d.

If the Internal Test is completed successfully, you may want to check that the I/O pins are working
correctly. To check this select External Test and follow the instruction provided. This will require you to
use the shorting wires supplied with the board to connect inputs to outputs for I/O testing.

e.

The “I/O Test Menu” lists the option “Plot”, select it and make the connections as shown to test your card.

6

3.0 HARDWARE CONNECTIONS

3.1 CONNECTOR PIN DIAGRAM

The PCI-DAS1200 and PCI-DAS1200/JR employ a 100-pin I/O connector. Please make accurate notes and pay
careful attention to wire connections. In a large system, a misplaced wire may create hours of work ‘fixing’
problems that do not exist. Note that pins 35, 36, 37, and 38 are for analog outputs and are therefore NC (no connec­tion) on the PCI-DAS1200/JR board. (Pin 77 is also NC on the /JR board).

Analog Ground 1

Analog Input Ch 0 H igh 2

Analog Input Ch 0 Low / 8 High 3

Analog Input Ch 1 H igh

Analog Input Ch 1 Low / 9 High

Analog Input Ch 2 H igh

Analog Input Ch 2 Low / 10 High

Analog Input Ch 3 H igh

Analog Input Ch 3 Low / 11 High

Analog Input Ch 4 High

Analog Input Ch 4 Low / 12 High

Analog Input Ch 5 High

Analog Input Ch 5 Low / 13 High

Analog Input Ch 6High

Analog Input Ch 6 Low / 14 High

Analog Input Ch 7 High

Analog Input Ch 7 Low / 15 High

Analog Ground 18

A/D External Pacer 42

A/D External Trigger 45

NC 19
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC

D/A GND 0 35

D/A OUT 0 36

D/A GND 1 37

D/A OUT 1 38

CLK 4 39

GATE 4 40

OUT 4 41

NC 43
NC 44

NC
NC

PC +5V 48

NC 49

PC Ground 50

10
11
12
13
14
15
16
17

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

46
47

4
5
6
7
8
9

51 Digital A0

D igita l A1

52

D igita l A2

53

D igita l A3

54

D igita l A4

55

D igita l A5

56

D igita l A6

57

D igita l A7

58

D igita l B0

59

D igita l B1

60

D igita l B2

61

D igita l B3

62

D igita l B4

63

D igita l B5

64

D igita l B6

65

D igita l B7

66

D igita l C0

67

D igita l C1

68

D igita l C2

69

D igita l C3

70

D igita l C4

71

D igita l C5

72

D igita l C6

73

D igita l C7

74
75 NC

N C

76

10 M H z O U T

77

N C

78

N C

79

CL K 6

80

GAT E 6

81

OUT 6

82

N C

83

N C

84

CL K 5

85

GAT E 5

86

OUT 5

87

N C

88

P C Gr o u nd

89
90 PC +12V
91 PC G round
92 PC -12V

N C

93

N C

94
95 A/D Internal Pacer Output

N C

96

N C

97

N C

98
99 NC
100 PC Ground

PCI-DAS1200 Connector Diagram

3.2 CONNECTING SIGNALS TO THE PCI-DAS1200

The 100-pin connector provides a far greater signal density than the traditional 37-pin D type connector. In
exchange for that density comes a far more complex cable and mating connector. The C100-FF-2 cable is a pair of
50-pin ribbon cables. At one end they are joined together with a 100-pin connector. From the 100-pin connector
designed to mate with the PCI-DAS1200 connector, the two 50-pin ribbon cables diverge and are terminated at the
other end with standard 50-pin header connectors. A CIO-MINI50 screw terminal board (or CIO-MINI50/DST with
detachable screw terminals) is the ideal way to terminate real-world signals and route them into the PCI-DAS1200.

7

4.0 ANALOG CONNECTIONS

4.1 ANALOG INPUTS

Analog signal connection is one of the most challenging aspects of applying a data acquisition board. If you are an
Analog Electrical Engineer, this section is not for you, but if you are like most PC data acquisition users, the best
way to connect your ana log inputs may no t be obvio us. Though c omplete cove rage of this topic is well beyond the
scope of this manual, the following section provides some explanations and helpful hints regarding these analog
input connections. This section is designed to help you achieve the optimum performance from your PCI-DAS1200
series board.

Prior to jumping into actual connection schemes, you should have at least a basic understanding of
single-ended/differential inputs and system grounding/isolation. If you are already comfortable with these concepts,
you may wish to skip to the next section (on wiring configurations).

4.1.1 Single-Ended and Differential Inputs

The PCI-DAS1200 provides either 8 differential or 16 single-ended input channels. The concepts of single-ended
and differential inputs are discussed in the following section.

Single-Ended Inputs

A single-ended input measures the voltage between the input signal and ground. In this case, in single-ended mode
the PCI-DAS1200 measures the voltage between the input channel and low level ground (LLGND). The single­ended input configuration requires only one physical connection (wire) per channel and allows the PCI-DAS1200 to
monitor more channels than the (2-wire) differential configuration using the same connector and onboard
multiplexor. However, because the PCI-DAS1200 is measuring the input voltage relative to its own low level
ground, single-ended inputs are more susceptible to both EMI (electromagnetic interference) and any ground noise at
the signal source. The following diagrams show the single-ended input configuration.

CH IN

LL GND

I/O

Connector

+

Inp u t

Amp

To A/D

-

Single-Ended Input

8

~

g

g

g

g

g

g

y

g

g

g

g

Vs

Vs + V

CH IN

2 - Vg1

LL GND

+

Input
Amp

To A /D

-

1

Any volta

1 and g2 shows up as an error signal

at the input amplifier

e differential between grounds

2

Single-ended input with Comm on M ode Voltage

Differential Inputs

Differential inputs measure the voltage between two distinct input signals. Within a certain range (referred to as the
common mode range), the measurement is almost independent of signal source to PCI-DAS1200 ground variations.
A differential input is also much more immune to EMI than a single-ended one. Most EMI noise induced in one lead
is also induced in the other, the input measures only the difference between the two leads, and the EMI common to
both is ignored. This effect is a major reason for twisted pair wire because the twisting ensures that both wires are
subject to virtually identical external influence. The diagram below shows a typical differential input configuration.

CH High

CH Low

+

-

Inp ut

Amp

To A/ D

LL GN D

I/O

Connector

Vs

~

Vcm = V

12

Common Mode Volta
b

differential input configuration. However,
no te th a t V cm + V s mu s t rema in w ithin
the amplifier’s com mon mode ran

Differential Input

Vs

Vcm

2 - Vg1

e (Vcm) is ignored

e of ±10V

CH High

CH Low

LL GND

+

Inp u t
Amp

-

Differential
Inp ut

To A/ D

9

Before moving on to the discussion of grounding and isolation, it is important to explain the concepts of common
mode, and common mode range (CM Range). Common mode voltage is depicted in the diagram above as Vcm.
Though differe ntial inputs measure the voltage b etween two signals, without (almost) respe ct to the either signal’s
voltages relative to ground, there is a limit to how far away from ground either signal can go. Though the
PCI-DAS1200 has differential inputs, it will not measure the difference between 100V and 101V as 1 Volt (in fact
the 100V would destroy the board!). This limitation or common mode range is depicted graphically in the following
diagram. The PCI-DAS1200 common mode range is +/- 10 Volts. Even in differential mode, no input signal can be
measured if it is more than 10V from the board’s low level ground (LLGND).

+13V
+12V
+11V
+10V
+9V
+8V
+7V
+6V
+5V
+4V
+3V
+2V
+1V

-1V

-2V

-3V

-4V

-5V

-6V

-7V

-8V

-9V

-10V

W ith V cm= + 5 V DC ,
+Vs must be less than +5V, or the common mode range will b e ex cee d e d (> + 1 0 V)

Gray area represents common m ode range
Both V+ and V- must alw ays remain within
the co mmo n m o d e ra nge relative to LL G nd

Vcm

4.1.2 System Grounds and Isolation

There are three scenarios possible when connecting your signal source to your PCI-DAS1200 board.

1. The PCI-DAS1200 and the signal source may have the same (or common)
ground. This signal source may be connected directly to the PCI-DAS1200.

2. The PCI-DAS1200 and the signal source may have an offset voltage
between their grounds (ac and/or dc). This offset is commonly
referred to as common mode voltage. Depending on the magnitude of
this voltage, it may or may not be possible to connect the PCI-DAS1200
directly to your signal source. We will discuss this topic further in a later
section.

3. The PCI-DAS1200 and the signal source may already have isolated
grounds. This signal source may be connected directly to the
PCI-DAS1200.

Which system do you have?

Try the following experiment. Using a battery powered voltmeter*, measure the voltage (difference) between the
ground signal at your signal source and at your PC. Place one voltmeter probe on the PC ground and the other on the
signal source ground. Measure both the ac and dc Voltages.

*If you do not have access to a voltmeter, skip this experiment and take a look a the following three sections. You may be able to
identify your system type from the descriptions provided.

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