National Instruments NI 6602, NI660, NI 6601, NI 6608 User Manual

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NI 660x User Manual

NI 6601, NI 6602, and NI 6608 Devices

NI 660x User Manual

December 2009
372119B-01

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for product installation requirements.

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Contents

About This Manual

Conventions ...................................................................................................................vii

Related Documentation..................................................................................................viii

Chapter 1
Introduction

About NI 660x Devices..................................................................................................1-1

Using PXI with CompactPCI.........................................................................................1-1

Getting Started ...............................................................................................................1-2

Installing NI-DAQ Driver Software................................................................1-2

Installing Other Software ................................................................................1-2

Installing the Hardware ...................................................................................1-2

Accessories and Cables..................................................................................................1-3

Chapter 2
Device Overview

Digital I/O ......................................................................................................................2-1

Prescaling.......................................................................................................................2-1

Pad Synchronization ......................................................................................................2-2

Duplicate Count Prevention...........................................................................................2-4

Example Application That Works Correctly (No Duplicate Counting)..........2-5

Example Application That Works Incorrectly (Duplicate Counting) .............2-6

Example Application That Prevents Duplicate Counting ...............................2-6

Enabling Duplicate Count Prevention in NI-DAQmx.....................................2-7

When to Use Duplicate Count Prevention.......................................................2-7

When Not to Use Duplicate Count Prevention................................................2-7

Transfer Rates ................................................................................................................2-8

High Precision Clock (NI 6608) ....................................................................................2-9

Using the OCXO as the SOURCE Counter ....................................................2-9

Using the OCXO as the 10 MHz PXI Backplane Clock.................................2-9

Measuring OCXO Stable Frequency Deviation ..............................................2-11

Calibration .....................................................................................................................2-12

Register-Level Programming Information.....................................................................2-12

© National Instruments Corporation v NI 660x User Manual

Contents

Chapter 3
Signal Connections

Programmable Function Interfaces (PFIs)..................................................................... 3-1

Digital Filtering ............................................................................................................. 3-1

Power-On State.............................................................................................................. 3-3

Pin Assignments ............................................................................................................ 3-3

I/O Connector Pinout..................................................................................................... 3-5

Outputs ..........................................................................................................................3-8

Counters......................................................................................................................... 3-10

Counter n Source Signal ................................................................................. 3-10

Counter n Gate Signal ..................................................................................... 3-12

Counter n Auxiliary Signal ............................................................................. 3-13

Counter n Internal Output Signal.................................................................... 3-14

Hardware Arm Start Triggers ......................................................................... 3-14

Counter Pairs................................................................................................... 3-15

Counter Applications ...................................................................................... 3-15

Real-Time System Integration Bus ............................................................................... 3-16

RTSI Triggers ................................................................................................. 3-16

+5 V Power Source........................................................................................................ 3-17

I/O Signals .....................................................................................................................3-18

Field Wiring Considerations ........................................................................... 3-18

Noise ............................................................................................................... 3-18

Crosstalk..........................................................................................................3-19

Inductive Effects ............................................................................................. 3-20

Transmission Line Effects .............................................................................. 3-22

Counter Source to Counter Out Delay.............................................. 3-12

Appendix A
Technical Support and Professional Services

Glossary

Index

NI 660x User Manual vi ni.com

About This Manual

This manual describes the electrical and mechanical aspects of the National
Instruments NI 6601, NI 6602, and NI 6608 devices, and contains
information about device operation and programming. Unless otherwise
noted, text applies to all NI 660x devices. The PCI and PXI
implementations are the same in functionality; their primary difference
is the bus interface.

Conventions

The following conventions appear in this manual:

<> Angle brackets that contain numbers separated by an ellipsis represent

a range of values associated with a bit or signal name—for example,
AO <3. .0>.

» The » symbol leads you through nested menu items and dialog box options

to a final action. The sequence File»Page Setup»Options directs you to
pull down the File menu, select the Page Setup item, and select Options
from the last dialog box.

This icon denotes a note, which alerts you to important information.

This icon denotes a caution, which advises you of precautions to take to
avoid injury, data loss, or a system crash. When this symbol is marked on a
product, refer to the Read Me First: Safety and Electromagnetic
Compatibility document for information about precautions to take.

bold Bold text denotes items that you must select or click in the software, such

as menu items and dialog box options. Bold text also denotes parameter
names.

italic Italic text denotes variables, emphasis, a cross-reference, or an introduction

to a key concept. Italic text also denotes text that is a placeholder for a word
or value that you must supply.

monospace Text in this font denotes text or characters that you should enter from the

keyboard, sections of code, programming examples, and syntax examples.
This font is also used for the proper names of disk drives, paths, directories,
programs, subprograms, subroutines, device names, functions, operations,
variables, filenames, and extensions.

© National Instruments Corporation vii NI 660x User Manual

About This Manual

Related Documentation

The following documents contain information that you may find helpful as
you read this manual:

• NI 660x Specifications—This document contains specifications for the
NI 6601, NI 6602, and NI 6608 devices.

• DAQ Getting Started guides—These guides describe how to install the
NI-DAQ driver software and the DAQ device, and how to confirm that
the device is operating properly.

• NI-DAQmx Help—This help file contains information about using
NI-DAQmx to program National Instruments devices. NI-DAQmx is
the software you use to communicate with and control your DAQ
device.

• Measurement & Automation Explorer Help for NI-DAQmx—This help
file contains information about configuring and testing DAQ devices,
SCXI devices, SCC devices, and RTSI cables using Measurement &
Automation Explorer (MAX) for NI-DAQmx, and information about
special considerations for operating systems.

• DAQ Assistant Help—This help file contains information about
creating and configuring channels, tasks, and scales using the DAQ
Assistant.

• PXI Hardware Specification Revision 2.1—This document introduces
the PXI architecture and describes the electrical, mechanical, and
software requirements for PXI.

Note Yo u can download these documents at ni.com/manuals.

NI 660x User Manual viii ni.com

Introduction

This chapter describes the NI 660x devices, lists what you need to get
started, and describes optional equipment. If you have not already installed
the TIO device, refer to the DAQ Getting Started guides.

About NI 660x Devices

The NI 660x devices are timing and digital I/O devices for use with the
PCI bus in PC-compatible computers, PXI chassis, or CompactPCI chassis.
The NI 6601 offers four 32-bit counter channels and up to 32 lines of
individually configurable, TTL/CMOS-compatible digital I/O. The
NI 6602 offers this capability and four additional 32-bit counter channels.
The NI 6608 is a functional superset of the NI 6602 device with a
high-stability clock called an oven-controlled crystal oscillator (OCXO).

The counter/timer channels have many measurement and generation
modes, such as event counting, time measurement, frequency
measurement, encoder position measurement, pulse generation, and
square-wave generation.

1

The NI 660x devices contain the National Instruments MITE PCI interface.
The MITE offers bus-master operation, PCI burst transfers, and high-speed
DMA controller(s) for continuous, scatter-gather DMA without requiring
DMA resources from your computer. Refer to the Using PXI with
CompactPCI section for more information about your NI PXI-660x device.

Device specifications are available in the NI 660x Specifications docu ment,
which is available for download from

ni.com/manuals.

Using PXI with CompactPCI

Using PXI-compatible products with CompactPCI products is an important
feature provided by PXI Hardware Specification Revision 2.1. If you use a
PXI-compatible plug-in module in a CompactPCI chassis, you cannot use
PXI-specific functions, but you can still use the basic plug-in device
functions. For example, the RTSI bus on a PXI TIO Series device is
available in a PXI chassis, but not in a CompactPCI chassis.

© National Instruments Corporation 1-1 NI 660x User Manual

Chapter 1 Introduction

Caution Damage can result if these lines are driven by the sub-bus. NI is not liable for any

damage resulting from improper signal connections.

Getting Started

The specification permits vendors to develop sub-buses that coexist with
the basic PCI interface on the bus. Compatible operation is not guaranteed
between devices with different sub-buses nor between devices with
sub-buses and PXI. The standard implementation for CompactPCI does not
include these sub-buses. The PXI TIO Series device works in any
CompactPCI chassis adhering to the PICMG 2.0 R3.0 core specification.

PXI-specific features are implemented on the J2 connector of the bus. The
PXI device is compatible with any chassis with a sub-bus that does not
drive the lines used by that device. Even if the sub-bus is capable of driving
these lines, the PXI device is still compatible as long as those pins on the
sub-bus are disabled by default and never enabled.

Before installing your DAQ device, you must install the software you plan
to use with the device.

Installing NI-DAQ Driver Software

If you are using NI-DAQ 7.1 or later, refer to the DAQ Getting Started
guides, which you can download at
Started guides offer NI-DAQ users step-by-step instructions for installing
software and hardware, configuring channels and tasks, and getting started
developing an application.

ni.com/manuals. The DAQ Getting

Installing Other Software

If you are using other software, refer to the installation instructions that
accompany your software.

Installing the Hardware

The DAQ Getting Started guides contain non-software-specific
information about how to install PCI, PXI, PCMCIA, and USB/IEEE 1394
devices, as well as accessories and cables.

NI 660x User Manual 1-2 ni.com

Accessories and Cables

Table 1-1 lists the accessories and cables available for use with
NI 660x devices.

Accessory Description

SH68-68-D1 Shielded 68-conductor cable

R6868 cable 68-conductor flat ribbon cable

BNC-2121 BNC connector block with built-in test features

CA-1000 Configurable connector accessory

SCB-68 Shielded screw connector block

TB-2715 Front-mount terminal block for NI PXI-660x

TBX-68 DIN-rail connector block

CB-68LP Low-cost screw connector block

CB-68LPR Low-cost screw connector block

Chapter 1 Introduction

Table 1-1. Accessories and Cables

© National Instruments Corporation 1-3 NI 660x User Manual

Device Overview

This chapter provides information about NI 660x device functionality.

Digital I/O

The NI 660x devices have a 32-bit DIO port on PFI <0..31>. Digital I/O
consists of asynchronous reads and writes to the digital port upon software
command. You can individually configure each line for digital input or
output. For output, you can individually configure PFI <8..31> for either
counter-associated output or digital output. You must specify whether you
are using the PFI line for counter I/O or digital I/O only if that line is being
used as an output. For input, both counter I/O and digital I/O can share the
lines on PFI <0..31>.

For more information about the signals that can be driven onto PFI lines,
refer to the I/O Connector Pinout section of this document.

For information about how to implement specific digital I/O functions,
refer to the application software documentation.

2

Prescaling

Prescaling allows the counter to count a signal that is faster than the
maximum timebase of the counter. The counters on the NI 660x offer
8X and 2X prescaling on each counter (prescaling can be disabled).
Each prescaler consists of a small, simple counter that counts to eight
(or two) and rolls over. This counter is specifically designed for this
application and can count signals that are faster than the general purpose
counters. The CtrnSource signal on the general purpose counter will be the
divided signal from the simple counter.

© National Instruments Corporation 2-1 NI 660x User Manual

Chapter 2 Device Overview

Figure 2-1 shows an example of prescaling.

External Signal

Prescaler Rollover

(Used as Source

by Counter)

Counter Value

Prescaling is intended for use with two counter period and frequency
measurements where the measurement is made on a continuous, repetitive
signal. The prescaling counter cannot be read, so you cannot determine how
many edges have occurred since the previous roll-over. You can also use
prescaling for counting edges if it is acceptable to have an error of up to
seven when using 8X prescaling or one when using 2X prescaling.

Pad Synchronization

The NI 660x devices allow synchronization of their PFI lines and RTSI
lines at the I/O pads. This is called pad synchronization in this document,
and digital synchronization in the NI-DAQmx API. You cannot use digital
filtering while enabling this feature.

01

Figure 2-1. Prescaling Example

Pad synchronization is useful when several counters are measuring or
operating off the same external signal. For example, suppose
counters 0 and 1 are configured for triggered pulse generation and each
counter uses the same external trigger (this external signal is connected to
PFI 38 on the I/O connector and both counters have PFI 38 selected as their
GATE). After the trigger signal propagates through the I/O pad of the
ASIC, the time for the signal to reach the GATE of each counter within the
ASIC may differ by a few nanoseconds.

This signal is sampled at the counters’ GATEs using the selected SOURCE.
Because of different propagation times for the paths to the two GATEs,
it is possible for the counters to detect the trigger on different edges on
SOURCE. Thus, one counter could see the trigger one SOURCE period
after the other. If you want to allow the counters to see the changes in the
signal at the same instance, you should use pad synchronization. During
pad synchronization, the signal is offset by one clock cycle.

NI 660x User Manual 2-2 ni.com

Chapter 2 Device Overview

Counter

Source

PFI 38

at CTR 0 GATE

PFI 38

at CTR 1 GATE

Sampled

GATE at Ctr0

Sampled

GATE at Ctr1

1/2 Cycles

1/4 Cycle

PFI 38

at Input To ASIC

This feature is useful in applications with two or more counters that are
armed by an external start trigger, or that use the same PFI line as a counter
control signal. Pad synchronization is only useful if the counters involved
are using one of the internal timebases. A counter is using maximum
timebase as its source if the synchronous counting mode is enabled for
that counter.

Figures 2-2 and 2-3 illustrate how pad synchronization can be useful.
These figures assume a 0.5 and a 0.75 SOURCE cycle delay between the
PFI 38 input pin, and CTR 0 GATE and CTR 1 GATE, respectively.
Figure 2-2 shows counter 0 at the gate edge on PFI 38 one source period
before counter 1. Figure 2-3 shows both counters at the gate edge on PFI 38
at the same time.

Figure 2-2. Counter 0 at Gate Edge on PFI 38 One Source Period before Counter 1

© National Instruments Corporation 2-3 NI 660x User Manual

Chapter 2 Device Overview

Counter

Source

PFI 38

at CTR 0 GATE

PFI 38

at CTR 1 GATE

Sampled

GATE at Ctr0

Sampled

GATE at Ctr1

1/2 Cycles

1/4 Cycle

PFI 38

at Input To ASIC

PFI 38

Synchronized at Pad

Figure 2-3. Counters 0 and 1 at Gate Edge on PFI 38 at the Same Time

Duplicate Count Prevention

NI 660x User Manual 2-4 ni.com

Duplicate count prevention (or synchronous counting mode) ensures that a
counter returns correct data in applications that are a slow or non-periodic
external source. Duplicate count prevention applies only to buffered
counter applications such as measuring frequency or period.

For such buffered applications, the counter should store the number of
times an external source pulses between rising edges on the Gate signal.

Chapter 2 Device Overview

Example Application That Works Correctly (No Duplicate Counting)

Figure 2-4 shows an external buffered signal as the period measurement
Source.

Rising Edge
of Gate

Counter detects rising edge
of Gate on the next rising
edge of Source.

Gate

Source

Counter Value

Buffer

67 12 1

7

2
7

Figure 2-4. Example Application That Works Correctly

On the first rising edge of the Gate, the current count of 7 is stored. On the
next rising edge of the Gate, the counter stores a 2 because two Source
pulses occurred after the previous rising edge of Gate.

The counter synchronizes or samples the Gate signal with the Source
signal. So the counter does not detect a rising edge in the Gate until the next
Source pulse. In this example, the counter stores the values in the buffer on
the first rising Source edge after the rising edge of Gate.

© National Instruments Corporation 2-5 NI 660x User Manual

Chapter 2 Device Overview

Example Application That Works Incorrectly (Duplicate Counting)

In Figure 2-5, after the first rising edge of Gate, no Source pulses occur.
So the counter does not write the correct data to the buffer.

No Source edge, so no
value written to buffer.

Gate

Source

Counter Value

Buffer

67 1

Figure 2-5. Example Application That Works Incorrectly

Example Application That Prevents Duplicate Counting

With duplicate count prevention enabled, the counter synchronizes
both the Source and Gate signals to the maximum onboard timebase.
By synchronizing to the timebase, the counter detects edges on the Gate
even if the Source does not pulse. This enables the correct current count to
be stored in the buffer even if no Source edges occur between Gate signals.
Figure 2-6 shows an example application that prevents duplicate counting.

Counter detects
rising Gate edge.

Gate

Source

80 MHz Timebase

7

Counter value
increments only
one time for each
Source pulse.

Counter Value

Buffer

670 1

7

0
7

Figure 2-6. Example Application That Prevents Duplicate Counting

NI 660x User Manual 2-6 ni.com

Even if the Source pulses are long, the counter increments only once for
each source pulse.

Normally, the counter and Counter n Internal Output signals change
synchronously to the Source signal. With duplicate count prevention, the
counter value and Counter n Internal Output signals change synchronously
to the maximum onboard timebase.

Notice that duplicate count prevention should only be used if the frequency
of the Source signal is one-fourth of the maximum onboard timebase.

Enabling Duplicate Count Prevention in NI-DAQmx

You can enable duplicate count prevention in NI-DAQmx by setting the
Enable Duplicate Count Prevention attribute/property. For specific
information on finding the Enable Duplicate Count Prevention
attribute/property, refer to the help file for the API you are using. Refer to
the NI-DAQmx Help for more information.

When to Use Duplicate Count Prevention

Use duplicate count prevention for buffered measurements that use an
external CtrnSource signal and the frequency of the signal is less than or
equal to one-fourth of the maximum onboard timebase. Use this mode if
you are using a low frequency or you expect zero CtrnSource edges
between successive edges of the CtrnGate signal.

Chapter 2 Device Overview

Yo u should use duplicate count prevention if the following conditions are
true:

•You are making a buffered counter input measurement.

•You are using an external signal (such as PFI x) as the counter Source.

• The frequency of the external source is one-fourth of the maximum
onboard timebase.

•You can have the counter value and outp
with the maximum onboard timebase.

In all other cases, you should not enable duplicate count prevention.

ut to change synchronously

When Not to Use Duplicate Count Prevention

Use duplicate counter prevention only for buffered measurements with an
external CtrnSource signal. Do not use it when the CtrnSource signal is
greater than one-fourth of the maximum timebase.

© National Instruments Corporation 2-7 NI 660x User Manual