National Instruments 6601 User manual

CB-68LP

DAQ
NI 660xUser Manual
NI 6601, NI 6602, and NI 6608 Devices
NI 660x User Manual
ni.com/manuals
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December 2012
372119C-01

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Electromagnetic Compatibility Information
This product was tested and complies with the regulatory requirements and limits for electromagnetic compatibility (EMC)
stated in the product specifications. These requirements and limits provide reasonable protection against harmful interference
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(10 feet).

©National Instruments vi NI 660x User Manual
Contents
About This Manual
Related Documentation..................................................................................................viii
Chapter 1
Introduction
Using PXI with CompactPCI.........................................................................................1-1
Installation .....................................................................................................................1-2
Accessories and Cables..................................................................................................1-2
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
Chapter 3
Signal Connections
Programmable Function Interfaces (PFIs) .....................................................................3-1
Digital Filtering..............................................................................................................3-1
Power-On State ..............................................................................................................3-3
I/O Connector Pinout .....................................................................................................3-3
Motion Encoder Context Pin Assignments....................................................................3-6
Outputs...........................................................................................................................3-7

Contents
NI 660x User Manual vii ni.com
Counters......................................................................................................................... 3-9
Counter nSource Signal ................................................................................. 3-9
Counter Source to Counter Out Delay.............................................. 3-11
Counter nGate Signal ..................................................................................... 3-11
Counter nAuxiliary Signal ............................................................................. 3-12
Counter nInternal Output Signal .................................................................... 3-13
Hardware Arm Start Triggers ......................................................................... 3-13
Counter Pairs................................................................................................... 3-14
Counter Applications ...................................................................................... 3-14
Real-Time System Integration Bus ............................................................................... 3-14
RTSI Triggers ................................................................................................. 3-15
+5 V Power Source........................................................................................................ 3-16
I/O Signals .....................................................................................................................3-17
Field Wiring Considerations ........................................................................... 3-17
Noise ............................................................................................................... 3-17
Crosstalk.......................................................................................................... 3-17
Inductive Effects ............................................................................................. 3-19
Transmission Line Effects .............................................................................. 3-21
Appendix A
Technical Support and Professional Services
Index

©National Instruments viii NI 660x User Manual
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 660xdevices. The PCI and PXI
implementations are the same in functionality; their primary difference
is the bus interface.
Related Documentation
The following documents contain information that youmay find helpful as
youread this manual:
• Read Me First: Safety and Electromagnetic Compatibility—Lists
precautions to take to avoid possible injury, data loss, or a system
crash.
•NI 660x Specifications—Contains all specifications for devices listed
in this manual.
•DAQ Getting Started guides—Explains installation of the NI-DAQ
driver software and the DAQ device, and how to confirm that the
device is operating properly.
•NI 6601/6602 Calibration Procedure—Contains instructions for
calibrating the NI 6601 and NI 6602.
•NI 6608 Timing I/O Device Calibration Procedure—Contains
instructions for calibrating the NI 6608.
•NI 660X Register-Level Programmer Manual—Describes the
programmable features and information necessary for the
programming of devices in this manual.
•NI-DAQmx Help—Contains API overviews, general information
about measurement concepts, key NI-DAQmx concepts, and common
applications that are applicable to all programming environments.
NI-DAQmx is the software youuse to communicate with and control
your DAQ device. Select Start»All Programs»National
Instruments»NI-DAQ»NI-DAQmx Help.
•Measurement & Automation Explorer Help—Contains information
about configuring and testing supported NI devices using
Measurement & Automation Explorer (MAX) for NI-DAQmx. For
more information, in Measurement& Automation Explorer (MAX),
select Help»Help Topics»NI-DAQmx»MAX Help for NI-DAQmx.

About This Manual
NI 660x User Manual ix ni.com
•DAQ Assistant Help—Contains information about creating and
configuring channels, tasks, and scales using the DAQ Assistant. For
more information, in Measurement& Automation Explorer (MAX),
select Help»Help Topics»NI-DAQmx»DAQ Assistant.
•PXI Hardware Specifications Revision 2.1—Introduces the PXI
architecture and describes the electrical, mechanical, and software
requirements for PXI. Available at http://www.pxisa.org.
•PICMG Specification 2.0 3.0—Details the CompactPCI Base
specification. Available at http://www.picmg.org.
Note Youcan download these documents at ni.com/manuals, unless stated otherwise.

©National Instruments 1-1 NI 660x User Manual
1
Introduction
This chapter describes the NI 660xdevices, lists what youneed to get
started, and describes optional equipment. If youhave not already installed
the TIO device, refer to the DAQ Getting Started documents.
The NI 660xdevices 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.
The NI 660xdevices 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-660xdevice.
Device specifications are available in the NI 660x Specifications document.
Using PXI with CompactPCI
Using PXI-compatible products with CompactPCI products is an important
feature provided by PXI Hardware Specification Revision 2.1. If youuse a
PXI-compatible plug-in module in a CompactPCI chassis, youcannot use
PXI-specific functions, but youcan 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.
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

Chapter 1 Introduction
NI 660x User Manual 1-2 ni.com
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.
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.
Installation
Before installing your DAQ device, youmust install the software youplan
to use with the device.
1. Installing application software—Refer to the installation
instructions that accompany your software.
2. Installing the NI-DAQmx—The DAQ Getting Started documents
contain step-by-step instructions for installing software and hardware,
configuring channels and tasks, and getting started developing an
application.
3. Installing the hardware—The DAQ Getting Started documents
contain non-software-specific information about how to install PCI,
PXI, PCMCIA, and USB/IEEE 1394 devices, as well as accessories
and cables.
Accessories and Cables
Table 1-1 lists the accessories and cables available for use with NI 660x
devices.
Caution This NI product must be operated with shielded cables and accessories to ensure
compliance with the Electromagnetic Compatibility (EMC) requirements defined in the
Specifications section of this document. Do not use unshielded cables or accessories unless
they are installed in a shielded enclosure with properly designed and shielded input/output
ports and connected to the NI product using a shielded cable. If unshielded cables or
accessories are not properly installed and shielded, the EMC specifications for the product
are no longer guaranteed.

Chapter 1 Introduction
©National Instruments 1-3 NI 660x User Manual
Table 1-1. Accessories and Cables
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-68A 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

©National Instruments 2-1 NI 660x User Manual
2
Device Overview
This chapter provides information about the functionality of NI 660x
devices.
Digital I/O
The NI 660xdevices 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. Youcan individually configure each line for digital input or
output. For output, youcan individually configure PFI <8..31> for either
counter-associated output or digital output. Youmust 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.
Prescaling
Prescaling allows the counter to count a signal that is faster than the
maximum timebase of the counter. The counters on the NI 660xdevices
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.

Chapter 2 Device Overview
NI 660x User Manual 2-2 ni.com
Figure 2-1 shows an example of prescaling.
Figure 2-1. Prescaling Example
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 youcannot determine how
many edges have occurred since the previous roll-over. Youcan 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 660xdevices 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. Youcannot use digital
filtering while enabling this feature.
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 youwant to allow the counters to see the changes in the
signal at the same instance, youshould use pad synchronization. During
pad synchronization, the signal is offset by one clock cycle.
External Signal
Counter Value
Prescaler Rollover
(Used as Source
by Counter)
01

Chapter 2 Device Overview
©National Instruments 2-3 NI 660x User Manual
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
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

Chapter 2 Device Overview
NI 660x User Manual 2-4 ni.com
Figure 2-3. Counters 0 and 1 at Gate Edge on PFI 38 at the Same Time
Duplicate Count Prevention
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.
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

Chapter 2 Device Overview
©National Instruments 2-5 NI 660x User Manual
Example Application That Works Correctly (No Duplicate Counting)
Figure 2-4 shows an external buffered signal as the period measurement
Source.
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.
Gate
Source
Counter Value
Buffer 2
7
7
67 12 1
Rising Edge
of Gate
Counter detects rising edge
of Gate on the next rising
edge of Source.

Chapter 2 Device Overview
NI 660x User Manual 2-6 ni.com
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.
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.
Figure 2-6. Example Application That Prevents Duplicate Counting
Gate
Source
Counter Value
Buffer 7
67 1
No Source edge, so no
value written to buffer.
Gate
Source
80 MHz Timebase
Counter Value
Buffer 0
7
7
670 1
Counter detects
rising Gate edge.
Counter value
increments only
one time for each
Source pulse.

Chapter 2 Device Overview
©National Instruments 2-7 NI 660x User Manual
Even if the Source pulses are long, the counter increments only once for
each source pulse.
Normally, the counter and Counter nInternal 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
Youcan 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 youare 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
youare using a low frequency or youexpect zero CtrnSource edges
between successive edges of the CtrnGate signal.
Youshould use duplicate count prevention if the following conditions are
true:
•Youare making a buffered counter input measurement.
•Youare 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.
•Youcan have the counter value and outputto change synchronously
with the maximum onboard timebase.
In all other cases, youshould not enable duplicate count prevention.
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.