Measurement Computing PCI-2515 User manual

PCI-2515
User's Guide
Document Revision 1, September, 2006
© Copyright 2006, Measurement Computing Corporation

3
HM PCI-2515.doc
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5
Table of Contents
Preface
About this User's Guide .......................................................................................................................7
What you will learn from this user's guide .........................................................................................................7
Conventions used in this user's guide .................................................................................................................7
Where to find more information.........................................................................................................................7
Chapter 1
Introducing the PCI-2515......................................................................................................................8
Overview: PCI-2515 features .............................................................................................................................8
Software features ................................................................................................................................................8
Chapter 2
Installing the PCI-2515..........................................................................................................................9
What comes with your PCI-2515 shipment? ......................................................................................................9
Hardware .......................................................................................................................................................................... 9
Additional documentation................................................................................................................................................10
Unpacking the PCI-2515 ..................................................................................................................................10
Installing the software ......................................................................................................................................10
Installing the hardware .....................................................................................................................................10
Configuring the hardware.................................................................................................................................11
Connecting the board for I/O operations ..........................................................................................................11
Connectors, cables – main I/O connector.........................................................................................................................11
Pin out – main I/O connector ...........................................................................................................................................12
Cabling .............................................................................................................................................................12
Field wiring and signal termination .................................................................................................................................13
Chapter 3
Programming and Developing Applications ....................................................................................14
Programming languages ...................................................................................................................................14
Packaged applications programs.......................................................................................................................14
Chapter 4
Functional Details ...............................................................................................................................15
PCI-2515 block diagram...................................................................................................................................15
Synchronous I/O – mixing analog, digital, and counter scanning ....................................................................15
Bus mastering DMA.........................................................................................................................................16
Analog input .....................................................................................................................................................16
Analog input scanning .....................................................................................................................................................16
Analog output ...................................................................................................................................................16
Digital I/O.........................................................................................................................................................17
Digital input scanning ......................................................................................................................................................18
Digital outputs and pattern generation .............................................................................................................................18
Triggering.........................................................................................................................................................18
Hardware analog triggering .............................................................................................................................................18
Digital triggering..............................................................................................................................................................19
Software-based triggering................................................................................................................................................19
Stop trigger modes ...........................................................................................................................................................19
Pre-triggering and post-triggering modes ........................................................................................................................19
Counter inputs ..................................................................................................................................................20

PCI-2515 User's Guide
6
Mapped channels .............................................................................................................................................................20
Counter modes .................................................................................................................................................................21
Debounce modes..............................................................................................................................................................22
Timer outputs....................................................................................................................................................25
Example: Timer outputs...................................................................................................................................................25
Multiple PCI-2515s per PC ..............................................................................................................................25
Chapter 5
Calibrating the PCI-2515.....................................................................................................................26
Chapter 6
Specifications......................................................................................................................................27
Analog input .....................................................................................................................................................27
Accuracy..........................................................................................................................................................................27
Analog outputs..................................................................................................................................................28
Digital input/output...........................................................................................................................................28
Counters............................................................................................................................................................29
Input sequencer.................................................................................................................................................29
Trigger sources and modes ...............................................................................................................................30
Frequency/pulse generators ..............................................................................................................................30
Power consumption ..........................................................................................................................................30
PCI compatibility..............................................................................................................................................30
Environmental ..................................................................................................................................................31
Mechanical .......................................................................................................................................................31
Main connector and pin out ..............................................................................................................................31

7
Preface
About this User's Guide
What you will learn from this user's guide
This user's guide explains how to install, configure, and use the PCI-2515 so that you get the most out of its
analog input, digital I/O, and counter/timer I/O features.
This user's guide also refers you to related documents available on our web site, and to technical support
resources that can also help you get the most out of these boards.
Conventions used in this user's guide
For more information on …
Text presented in a box signifies additional information and helpful hints related to the subject matter you are
reading.
Caution! Shaded caution statements present information to help you avoid injuring yourself and others,
damaging your hardware, or losing your data.
<#:#> Angle brackets that enclose numbers separated by a colon signify a range of numbers, such as those assigned
to registers, bit settings, etc.
bold text Bold text is used for the names of objects on the screen, such as buttons, text boxes, and check boxes. For
example:
1. Insert the disk or CD and click the OK button.
italic text Italic text is used for the names of manuals and help topic titles, and to emphasize a word or phrase. For
example:
The InstaCal installation procedure is explained in the Quick Start Guide.
Never touch the exposed pins or circuit connections on the board.
Where to find more information
The following electronic documents provide information that can help you get the most out of your PCI-2515.
MCC's Specifications: PCI-2515 (the PDF version of the Specifications chapter in this guide) is available
on our web site at www.mccdaq.com/pdfs/PCI-2515.pdf.
MCC's Quick Start Guide is available on our web site at
www.mccdaq.com/PDFmanuals/DAQ-Software-Quick-Start.pdf.
MCC's Guide to Signal Connections is available on our web site at
www.mccdaq.com/signals/signals.pdf.
MCC's Universal Library User's Guide is available on our web site at
www.mccdaq.com/PDFmanuals/sm-ul-user-guide.pdf.
MCC's Universal Library Function Reference is available on our web site at
www.mccdaq.com/PDFmanuals/sm-ul-functions.pdf.
MCC's Universal Library for LabVIEW™User’s Guide is available on our web site at
www.mccdaq.com/PDFmanuals/SM-UL-LabVIEW.pdf.
PCI-2515 User's Guide (this document) is also available on our web site at
www.mccdaq.com/PDFmanuals/PCI-2515.pdf.

8
Chapter 1
Introducing the PCI-2515
Overview: PCI-2515 features
The PCI-2515 is supported under popular Microsoft®Windows®operating systems.
The PCI-2515 board is a multifunction measurement and control board designed for the PCI bus.
The PCI-2515 provides either eight differential or 16 single-ended analog inputs with 16-bit resolution. It offers
seven software-selectable analog input ranges of ±10 V, ±5 V, ±2 V, ±1 V, ±0.5 V, ±0.2 V, and ±0.1V.
The PCI-2515 also has two 16-bit, 1 MHz analog output channels with an output range of -10V to +10V.
The board has 24 high-speed lines of digital I/O, two timer outputs, and four 32-bit counters. It provides up to
12 MHz scanning on all digital input lines.
You can operate all analog I/O, digital I/O, and counter/timer I/O synchronously and simultaneously.
Software features
For information on the features of InstaCal and the other software included with your PCI-2515, refer to the
Quick Start Guide that shipped with your device. The Quick Start Guide is also available in PDF at
www.mccdaq.com/PDFmanuals/DAQ-Software-Quick-Start.pdf.
Check www.mccdaq.com/download.htm for the latest software version or versions of the software supported
under less commonly used operating systems.

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Chapter 2
Installing the PCI-2515
What comes with your PCI-2515 shipment?
As you unpack your PCI-2515, verify that the following components are included.
Hardware
PCI-2515
Optional components
Cables and signal conditioning accessories that are compatible with the PCI-2515 are not included with PCI-
2515 orders, and must be ordered separately.
If you ordered any of the following products with your board, they should be included with your shipment.
Cables
CA-68-3R
CA-68-3S (3-feet) and CA-68-6S (6-feet)
Signal conditioning accessories
MCC provides signal termination products for use with the PCI-2515. Refer to the "Field wiring and signal
termination" section for a complete list of compatible accessory products.

PCI-2515 User's Guide Installing the PCI-2515
10
Additional documentation
In addition to this hardware user's guide, you should also receive the Quick Start Guide (available in PDF at
www.mccdaq.com/PDFmanuals/DAQ-Software-Quick-Start.pdf). This booklet supplies a brief description of
the software you received with your PCI-2515 and information regarding installation of that software. Please
read this booklet completely before installing any software or hardware.
Unpacking the PCI-2515
As with any electronic device, you should take care while handling to avoid damage from static
electricity. Before removing the PCI-2515 from its packaging, ground yourself using a wrist strap or by simply
touching the computer chassis or other grounded object to eliminate any stored static charge.
If any components are missing or damaged, notify Measurement Computing Corporation immediately by
phone, fax, or e-mail:
Phone: [phone] and follow the instructions for reaching Tech Support.
Fax: [phone] to the attention of Tech Support
Email: [email protected]
Installing the software
Refer to the Quick Start Guide for instructions on installing the software on the Measurement Computing Data
Acquisition Software CD. This booklet is available in PDF at www.mccdaq.com/PDFmanuals/DAQ-Software-
Quick-Start.pdf.
Installing the hardware
The PCI-2515 board is completely plug-and-play. There are no switches or jumpers to set on the board.
Configuration is controlled by your system's BIOS.
Before you install the PCI-2515…
Enable Bus Mastering DMA: For a PCI-2515 to operate properly, you must enable Bus Mastering DMA on the
PCI slot where you will install the board. Make sure that your computer can perform Bus Mastering DMA for
the applicable PCI slot. Some computers have BIOS settings that enable and disable Bus Mastering DMA. If
your computer has this BIOS option, make sure you enable Bus Mastering DMA on the appropriate PCI slot.
Refer to your PC Owner's Manual for additional information regarding your PC and enabling Bus Mastering
DMA for PCI slots.
Install the MCC DAQ software: The driver needed to run your PCI-2515 is installed with the MCC DAQ
software. Therefore, you need to install the MCC DAQ software before you install your board. Refer to the
Quick Start Guide for instructions on installing the software.
To install your PCI-2515, follow the steps below.
1. Turn your computer off, open it up, and insert your board into an available PCI slot that has Bus Mastering
DMA enabled.
2. Close your computer and turn it on.
A dialog opens as the system loads indicating that new hardware has been detected. If the information file
for this board is not already loaded onto your PC, you are prompted for the disk containing this file. The
MCC DAQ software contains this file. If required, insert the Measurement Computing Data Acquisition
Software CD and click OK.

PCI-2515 User's Guide Installing the PCI-2515
11
3. To test your installation and configure your board, run the InstaCal utility installed in the previous section.
Refer to the Quick Start Guide that came with your board for information on how to initially set up and
load InstaCal.
If your board has been powered-off for more than 10 minutes, allow your computer to warm up for at least
30 minutes before acquiring data. This warm-up period is required in order for the board to achieve its rated
accuracy. The high speed components used on the board generate heat, and it takes this amount of time for a
board to reach steady state if it has been powered off for a significant amount of time.
Configuring the hardware
All hardware configuration options on the PCI-2515 are software-controlled. You can select some of the
configuration options using InstaCal, such as the analog input configuration (16 single-ended or eight
differential channels), and the edge used for pacing when using an external clock. Once selected, any program
that uses the Universal Library initializes the hardware according to these selections.
Information on signal connections
General information regarding signal connection and configuration is available in the Guide to Signal
Connections. This document is available on our web site at www.mccdaq.com/signals/signals.pdf).
Connecting the board for I/O operations
Connectors, cables – main I/O connector
Table 2-1 lists the board connectors, applicable cables, and compatible accessory products for the PCI-2515.
Table 2-1. Board connectors, cables, and compatible hardware
Connector type 68-pin standard "SCSI TYPE III" female connector
HDMI connector (targeted for future expansion)
Compatible cables (for the 68-pin SCSI connector) CA-68-3R — 68-pin ribbon cable; 3 feet.
CA-68-3S — 68-pin shielded round cable; 3 feet.
CA-68-6S — 68-pin shielded round cable; 6 feet.
Compatible accessory products TB-100 terminal connector
RM-TB-100

PCI-2515 User's Guide Installing the PCI-2515
12
Pin out – main I/O connector
Table 2-2. PCI-2515 pin out
Signal name Pin Pin Signal name
ACH0 (ACH0 HI) 68 ••34 ACH8 (ACH0 LO)
AGND 67
••33 ACH1 (ACH1 HI)
ACH9 (ACH1 LO) 66 ••32 AGND
ACH2 (ACH2 HI) 65 ••31 ACH10 (ACH2 LO)
AGND 64
••30 ACH3 (ACH3 HI)
ACH11 (ACH3 LO) 63 ••29 AGND
SGND 62
••28 ACH4 (ACH4 HI)
ACH12 (ACH4 LO) 61 ••27 AGND
ACH5 (ACH5 HI) 60 ••26 ACH13 (ACH5 LO)
AGND 59
••25 ACH6 (ACH6 HI)
ACH14 (ACH6 LO) 58 ••24 AGND
ACH7 57
••23 ACH15
NC 56
••22 XDAC0
NC 55
••21 XDAC1
NEGREF 54
••20 POSREF
GND 53
••19 +5V
A1 52
••18 A0
A3 51
••17 A2
A5 50
••16 A4
A7 49
••15 A6
B1 48
••14 B0
B3 47
••13 B2
B5 46
••12 B4
B7 45
••11 B6
C1 44
••10 C0
C3 43
••9 C2
C5 42
••8 C4
C7 41
••7 C6
GND 40
••6 TTL TRG
CNT1 39
••5 CNT0
CNT3 38
••4 CNT2
TMR1 37
••3 TMR0
GND 36
••2 XAPCR
GND 35
••1 XDPCR
PCI slot ↓
Cabling
Use a CA-68-3R 68-pin ribbon expansion cable (Figure 2-1), or a CA-68-3S (3-foot) or CA-68-6S (6-foot) 68-
pin shielded expansion cable (Figure 2-2) to connect signals to the PCI-2517 board.)
The stripe
identifies pin # 1
6834
351
68
35
34
1

PCI-2515 User's Guide Installing the PCI-2515
13
Figure 2-1. CA-68-3R cable
6834
135
34
1
68
35
Figure 2-2. CA-68-3S and CA-68-6S cable
Field wiring and signal termination
You can use the following MCC screw terminal board to terminate field signals and route them into the PCI-
2515 board using the CA-68-3R, CA-68-3S, or CA-68-6S cable:
TB-100: Termination board with screw terminals. Details on this product are available on our web site at
www.mccdaq.com/cbicatalog/cbiproduct.asp?dept_id=98&pf_id=1787.
RM-TB-100: 19-inch rack mount kit for the TB-100 termination board. Details on this product are available
on our web site at www.mccdaq.com/cbicatalog/cbiproduct.asp?dept_id=98&pf_id=1786.

14
Chapter 3
Programming and Developing Applications
After following the installation instructions in Chapter 2, your PCI-2515 should now be installed and ready for
use. Although the board is part of the larger Measurement Computing hardware family, in general there may be
no correspondence among registers for different boards. Software written at the register level for other models
will not function correctly with your board.
Programming languages
Measurement Computing's Universal Library provides access to board functions from a variety of Windows
programming languages. If you are planning to write programs, or would like to run the example programs for
Visual Basicor any other language, please refer to the Universal Library User's Guide (available on our web
site at www.mccdaq.com/PDFmanuals/sm-ul-user-guide.pdf).
Packaged applications programs
Many packaged application programs—such as SoftWIREand DASYLab™— now have drivers for your
board. If the package you own does not have drivers for the board, please fax or e-mail the package name and
the revision number from the install disks. We will research the package for you and advise how to obtain
drivers.
Some application drivers are included with the Universal Library package, but not with the application package.
If you have purchased an application package directly from the software vendor, you may need to purchase our
Universal Library and drivers. Please contact us by phone, fax or e-mail:
Phone: [phone] and follow the instructions for reaching Tech Support.
Fax: [phone] to the attention of Tech Support
Email: [email protected]
For information on Measurement Computing applications that you can use with the PCI-2515, refer to the
PCI-2515 product page at www.mccdaq.com/cbicatalog/cbiproduct_new.asp?dept_id=139&pf_id=1782.

15
Chapter 4
Functional Details
This chapter contains detailed information on all of the features available from the board, including:
a block diagram of board
information how, when, and when not to use the signals generated by the board
diagrams of signals using default or conventional board settings
PCI-2515 block diagram
Figure 4-1 is a simplified block diagram of the PCI-2515. This board provides all of the functional elements
shown in the figure.
Figure 4-1. PCI-2515 functional block diagram
Synchronous I/O – mixing analog, digital, and counter scanning
The PCI-2515 can read analog, digital, and counter inputs, while generating up to two analog outputs and digital
pattern outputs at the same time. Digital and counter inputs do not affect the overall A/D rate because these
inputs use no time slot in the scanning sequencer.
For example, one analog input channel can be scanned at the full 1 MHz A/D rate along with digital and counter
input channels. Each analog channel can have a different gain, and counter and digital channels do not need
additional scanning bandwidth as long as there is at least one analog channel in the scan group.
Digital input channel sampling is not done during the "dead time" of the scan period where no analog sampling
is being done either.

PCI-2515 User's Guide Functional Details
16
The ability to scan digital and counter channels along with analog channels provides for a more deterministic
collection of data.
Bus mastering DMA
The PCI-2515 supports bus mastering DMA. With multiple DMA channels, analog, digital, and counter input
data, as well as digital output data, can flow between the PC and the PCI-2515 without consuming valuable
CPU time. The driver supplied with the PCI-2515 automatically uses bus mastering DMA to efficiently conduct
I/O from the PC to the PCI-2515.
Analog input
The PCI-2515 has a 16-bit, 1-MHz A/D coupled with 16 single-ended, or eight differential analog inputs. Seven
software programmable ranges provide inputs from ±10 V to ±100 mV full scale.
Analog input scanning
The PCI-2515 has several scanning modes to address various applications. You can load the 512-location scan
buffer with any combination of analog input channels. All analog input channels in the scan buffer are measured
sequentially at 1 µs per channel.
For example, in the fastest mode, with a 0 delay between the end of scan and the start of scan, a single analog
channel can be scanned continuously at 1 MS/s; two analog channels can be scanned at 500 kS/s each; 16
analog input channels can be scanned at 62.5 kS/s.
Example: Analog channel scanning of voltage inputs
Figure 4-2 shows a simple acquisition. The scan is programmed pre-acquisition and is made up of six analog
channels (Ch0, Ch1, Ch3, Ch4, Ch6, Ch7). Each of these analog channels can have a different gain. The
acquisition is triggered and the samples stream to the PC via DMA. Each analog channel requires one
microsecond of scan time—therefore the scan period can be no shorter than 6 µs for this example. The scan
period can be made much longer than 6 µs—up to 1 second. The maximum scan frequency is 1 divided by 6 µs
or 166,666 Hz.
Figure 4-2. Analog channel scan of voltage inputs example
Analog output
The PCI-2515 has two 16-bit, 1 MHz analog output channels.
The channels have an output range of -10V to +10V. Through the use of Bus Mastering DMA, each D/A output
can continuously output a waveform at up to 1 MHz. In addition, a program can asynchronously output a value
When used to generate waveforms, you can clock the D/As in several different modes.

PCI-2515 User's Guide Functional Details
17
Asynchronous internal clock:The on-board programmable clock can generate updates ranging from 1 Hz
to 1 MHz, independent of any acquisition rate..
External clock.A user-supplied external input clock can pace both the D/A and the analog input.
Example: Analog channel scanning of voltage inputs and streaming analog outputs
The example shown in Figure 4-3 adds two DACs a 16-bit digital pattern output to the example presented in
Figure 4-2.
Figure 4-3. Analog channel scan of voltage inputs and streaming analog outputs example
This example updates both DACs and the 16-bits of digital I/O. These updates happen at the same time as the
acquisition pacer clock—also called the scan clock. Both DACs and the 16-bits of pattern digital output are
updated at the beginning of each scan.
Due to the time it takes to shift the digital data out to the DACs, plus the actual settling time of the digital-to-
analog conversion, the DACs actually take up to 4 µs after the start of scan to settle on the updated value.
The data for the DACs and pattern digital output comes from a PC-based buffer. The data is streamed across the
PCI bus to the PCI-2515 by the DMA.
You can update the DACs and pattern digital output with the DAC pacer clock—either internally-generated or
externally-applied. In this scenario, the acquisition input scans are not synchronized to the analog outputs or
pattern digital outputs.
You can also synchronize everything—input scans, DACs, pattern digital outputs—to one clock, which is either
internally-generated or externally-applied.
Digital I/O
Twenty-four TTL-level digital I/O lines are included in each PCI-2515. You can program digital I/O in 8-bit
groups as either inputs or outputs and scan them in several modes (see "Digital input scanning" on page 18).
You can access input ports asynchronously from the PC at any time, including when a scanned acquisition is
occurring.

PCI-2515 User's Guide Functional Details
18
Digital input scanning
Digital input ports can be read asynchronously before, during, or after an analog input scan.
Digital input ports can be part of the scan group and scanned along with analog input channels. Two
synchronous modes are supported when digital inputs are scanned along with analog inputs.
In both modes, adding digital input scans has no affect on the analog scan rate limitations.
If no analog inputs are being scanned, the digital inputs can be scanned at up to 12 MHz.
Digital outputs and pattern generation
Digital outputs can be updated asynchronously at anytime before, during, or after an acquisition. You can use
two of the 8-bit ports to generate a digital pattern at up to 12 MHz. The PCI-2515 supports digital pattern
generation with bus mastering DMA. The digital pattern can be read from PC RAM.
Digital pattern generation is clocked using an internal clock. The on-board programmable clock generates
updates ranging from once every 1 second to 1 MHz, independent of any acquisition rate.
Triggering
Triggering can be the most critical aspect of a data acquisition application. The PCI-2515 supports the
following trigger modes to accommodate certain measurement situations.
Hardware analog triggering
The PCI-2515 uses true analog triggering in which the trigger level you program sets an analog DAC, which is
then compared in hardware to the analog input level on the selected channel. This guarantees an analog trigger
latency that is less than 1 µs.
You can select any analog channel as the trigger channel, but the selected channel must be the first channel in
the scan. You can program the trigger level, the rising or falling edge, and hysteresis.
Concerning hardware analog level trigger and comparator change state
When analog input voltage starts near the trigger level, and you are performing a rising or falling] hardware
analog level trigger, the analog level comparator may have already tripped before the sweep was enabled. If this
is the case, the circuit waits for the comparator to change state. However, since the comparator has already
changed state, the circuit does not see the transition.
To resolve this problem, do the following:
1. Set the analog level trigger to the threshold you want.
2. Apply an analog input signal that is more than 2.5% of the full-scale range away from the desired
threshold. This ensures that the comparator is in the proper state at the beginning of the acquisition.
3. Bring the analog input signal toward the desired threshold. When the input signal is at the threshold (±
some tolerance) the sweep will be triggered.
4. Before re-arming the trigger, again move the analog input signal to a level that is more than 2.5% of the
full-scale range away from the desired threshold.
For example, if you are using the ±2 V full-scale range (gain = 5), and you want to trigger at +1 V on the rising
edge, you would set the analog input voltage to a start value that is less than +0.9 V (1 V – (2 V * 2 * 2.5%)).

PCI-2515 User's Guide Functional Details
19
Digital triggering
A separate digital trigger input line is provided, allowing TTL-level triggering with latencies guaranteed to be
less than 1 µs. You can program both of the logic levels (1 or 0) and the rising or falling edge for the discrete
digital trigger input.
Software-based triggering
The three software-based trigger modes differ from hardware analog triggering and digital triggering because
the readings—analog, digital, or counter—are checked by the PC in order to detect the trigger event.
Analog triggering
You can select any analog channel in the scan as the trigger channel. You can program the trigger level, the
rising or falling edge, and hysteresis.
Pattern triggering
You can select any scanned digital input channel pattern to trigger an acquisition, including the ability to mask
or ignore specific bits.
Counter triggering
You can program triggering to occur when one of the counters meets or exceeds a set value, or is within a range
of values. You can program any of the included counter channels as the trigger source.
Software-based triggering usually results in long period of inactivity between the trigger condition being
detected and the data being acquired. However, the PCI-2515 avoids this situation by using pre-trigger data.
When software-based-triggering is used, and the PC detects the trigger condition—which may be thousands of
readings after the actual occurrence of the signal—the PCI-2515 driver automatically looks back to the location
in memory where the actual trigger-causing measurement occurred, and presents the acquired data that begins at
the point where the trigger-causing measurement occurs. The maximum inactive period in this mode equals one
scan period.
Set pre-trigger > 0 when using counter as trigger source
When using a counter for a trigger source, you should use a pre-trigger with a value of at least 1. Since all
counters start at zero with the first scan, there is no valid reference in regard to rising or falling edge. Setting a
pre-trigger to 1 or more ensures that a valid reference value is present, and that the first trigger will be
legitimate.
Stop trigger modes
You can use any of the software trigger modes explained previously to stop an acquisition.
For example, you can program an acquisition to begin on one event—such as a voltage level—and then stop on
another event—such as a digital pattern.
Pre-triggering and post-triggering modes
The PCI-2515 supports four modes of pre-triggering and post-triggering, providing a wide-variety of options to
accommodate any measurement requirement.
When using pre-trigger, you must use software-based triggering to initiate an acquisition.

PCI-2515 User's Guide Functional Details
20
No pre-trigger, post-trigger stop event.
In this simple mode, data acquisition starts when the trigger is received, and the acquisition stops when the stop-
trigger event is received.
Fixed pre-trigger with post-trigger stop event
In this mode, you set the number of pre-trigger readings to acquire. The acquisition continues until a stop-
trigger event occurs.
No pre-trigger, infinite post-trigger
In this mode, no pre-trigger data is acquired. Instead, data is acquired beginning with the trigger event, and is
terminated when you issue a command to halt the acquisition.
Fixed pre-trigger with infinite post-trigger
You set the amount of pre-trigger data to acquire. Then, the system continues to acquire data until the program
issues a command to halt acquisition.
Counter inputs
Four 32-bit counters are built into the PCI-2515. Each counter accepts frequency inputs up to 20 MHz.
The counters can concurrently monitor time periods, frequencies, pulses, and other event driven incremental
occurrences directly from pulse-generators, limit switches, proximity switches, and magnetic pick-ups.
Counter inputs can be read asynchronously under program control, or synchronously as part of an analog or
digital scan group.
When reading synchronously, all counters are set to zero at the start of an acquisition. When reading
asynchronously, counters may be cleared on each read, count up continually, or count until the 16 bit or 32 bit
limit has been reached. See counter mode descriptions below.
Figure 4-4. Typical PCI-2515 counter channel
Mapped channels
A mapped channel is one of four counter input signals that can get multiplexed into a counter module. The
mapped channel can participate with the counter's input signal by gating the counter, latching the counter, and
so on. The four possible choices for the mapped channel are the four counter input signals (post-debounce).