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Chapter 2

Digital I/O

NI PCI-8254R User Manual

2-2

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NI-IMAQ I/O devices such as the such as the NI 8254R, the NI 8255R, and 
the CVS-1450 Series Compact Vision Systems have 29 digital I/O lines 
with built-in functionality for communicating with external devices, such 
as reading quadrature encoder inputs, generating strobe pulses, and writing 
to or reading from digital lines.

NI-IMAQ I/O devices have 15 digital input lines—13 isolated 24 V lines 
and two dedicated TTL lines. There are 14 digital output lines—four 
isolated 24 V lines and 10 dedicated TTL lines. Using these signals, you 
can dynamically control your lighting or cameras, synchronize with a 
conveyor belt, or communicate with relays that control solenoids and other 
actuators.

TTL Inputs and Outputs

TTL is a fast-switching 5 V digital signaling standard commonly used for 
applications that require high precision, such as camera triggering. TTL 
inputs and outputs do not require a separate power supply.

Caution

Do not connect voltage or current sources to TTL outputs. Doing so could 

damage the NI 8254R device.

Table 2-1 summarizes the TTL inputs and outputs available on the 
NI 8254R.

Table 2-1.  NI 8254R TTL Inputs and Outputs

Primary 

Function

Input 

or 

Output

Number 

Available

Signal Names

44-Pin 

D-SUB on 

NI 8255R 

Device Pin 

Number

37-Pin 

Terminal 

Block 

Number

Trigger

Input

2

TTL Input 0,

General Purpose

*

TTL Input 1,

General Purpose

*

1

16

1

2

Timed 
Pulse

Output

6

TTL Output 1, Pulse 1
TTL Output 2, Pulse 2
TTL Output 3, Pulse 3

TTL Output 4, Pulse

TRIG 1, Pulse 5
TRIG 2, Pulse 6

4
6
7

18
24 

9

5
7
8

20
— 

Summary of Contents for NI VISION PCI-8254R

Page 1: ...NI Vision NI PCI 8254R User Manual 1394a Image Acquisition Device with Reconfigurable I O NI PCI 8254R User Manual September 2006 371578C 01 ...

Page 2: ...ea 82 02 3451 3400 Lebanon 961 0 1 33 28 28 Malaysia 1800 887710 Mexico 01 800 010 0793 Netherlands 31 0 348 433 466 New Zealand 0800 553 322 Norway 47 0 66 90 76 60 Poland 48 22 3390150 Portugal 351 210 311 210 Russia 7 095 783 68 51 Singapore 1800 226 5886 Slovenia 386 3 425 4200 South Africa 27 0 11 805 8197 Spain 34 91 640 0085 Sweden 46 0 8 587 895 00 Switzerland 41 56 200 51 51 Taiwan 886 02...

Page 3: ...storing in an information retrieval system or translating in whole or in part without the prior written consent of National Instruments Corporation National Instruments respects the intellectual property of others and we ask our users to do the same NI software is protected by copyright and other intellectual property laws Where NI software may be used to reproduce software or other materials belo...

Page 4: ...nt of Communications DOC Changes or modifications not expressly approved by NI could void the user s authority to operate the equipment under the FCC Rules Class A Federal Communications Commission This equipment has been tested and found to comply with the limits for a Class A digital device pursuant to part 15 of the FCC Rules These limits are designed to provide reasonable protection against ha...

Page 5: ...vising you to take precautions to avoid electrical shock 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 s...

Page 6: ...n 2 4 Trigger Inputs 2 5 Timed Pulse Output 2 5 Initiating a Timed Pulse 2 5 Pulse Modes 2 6 Pulse Delay 2 6 Pulse Width 2 7 Trigger Polarity 2 7 Trigger Change Detectors 2 8 Quadrature Encoder 2 8 Product Selection Port 2 8 Using ISO Input 5 as a Latch 2 9 General Purpose I O 2 9 General Purpose Inputs 2 9 General Purpose Outputs 2 10 I O for Fault Conditions 2 10 Shutdown 2 11 Watchdog Timer 2 1...

Page 7: ...r Connector 3 2 IEEE 1394a Connector 3 3 General Purpose Digital I O 3 3 Cabling 3 8 IEEE 1394 Camera Cables 3 8 I O Terminal Block 3 9 NI Vision I O Terminal Block and Prototyping Accessory 3 9 Power Requirements 3 9 Isolated Outputs Power Connector 3 9 Appendix A Technical Support and Professional Services Glossary Index ...

Page 8: ... is an FPGA which has been preconfigured with the functionality required for most common machine vision tasks However if the factory configured functionality does not fulfill your requirements the FPGA is user configurable with the LabVIEW FPGA Module The NI 8254R provides a convenient 44 pin D SUB connector on its front panel to access its digital I O For detailed specifications of the NI 8254R r...

Page 9: ...lso can migrate the configured inspection to LabVIEW extending the capabilities of the applications if necessary Vision Development Module NI Vision Development Module which consists of NI Vision and NI Vision Assistant is an image acquisition processing and analysis library of more than 270 functions for the following common machine vision tasks Pattern matching Particle analysis Gauging Taking m...

Page 10: ...puters and peripheral devices It features simplified cabling via twisted pairs hot swapping and transfer speeds of up to 400 megabits per second You can support up to 63 devices on the high speed bus with IEEE 1394 The IEEE 1394a standard offers up to 400 Mb s bandwidth The NI 8254R provides two direct connect IEEE 1394a ports but more IEEE 1394 devices can be added with the addition of IEEE 1394 ...

Page 11: ...cquisition on a rising or falling edge Acquisition Window Control You can configure the following parameter on the NI 8254R to control the video acquisition window Acquisition window The NI 8254R and the IIDC 1394 based Digital Camera Specification allow you to specify a particular region of active pixels and lines on a camera to acquire In many cases specifying a smaller acquisition window will i...

Page 12: ...hind the digital I O of the NI 8254R is an FPGA which has been preconfigured with the functionality required for most common machine vision tasks If the factory configured functionality does not fulfill your requirements the FPGA is user configurable with the LabVIEW FPGA Module RIO technology found throughout the NI platform includes NI PCI and PXI R Series DAQ devices NI CVS 1450 Series Compact ...

Page 13: ...cate with relays that control solenoids and other actuators TTL Inputs and Outputs TTL is a fast switching 5 V digital signaling standard commonly used for applications that require high precision such as camera triggering TTL inputs and outputs do not require a separate power supply Caution Do not connect voltage or current sources to TTL outputs Doing so could damage the NI 8254R device Table 2 ...

Page 14: ...er connector Note Viso is referred to as V and Ciso is referred to as C on the 2 position isolated outputs power connector on the NI 8254R Note The isolated outputs have current limiting protection circuitry If this circuitry is tripped you can re enable the outputs by removing the fault and restarting your computer Watchdog Output 1 TTL Output 0 3 4 General Purpose Output 3 TTL Output 5 TTL Outpu...

Page 15: ...lock Number Trigger Input 3 TRIG 0 ISO Input 5 ISO Input 8 11 35 40 15 27 Quadrature Encoder Input 1 ISO Input 6 ISO Input 7 37 38 25 26 External Shutdown Control Input 1 ISO Input 11 44 31 Product Selection Port Input 1 ISO Input 0 ISO Input 1 ISO Input 2 ISO Input 3 ISO Input 4 15 30 31 32 34 9 10 11 13 14 General Purpose Input 2 ISO Input 9 ISO Input 10 41 43 29 30 General Purpose Output 4 ISO ...

Page 16: ...nals such as camera exposure This section describes the various uses for the timed pulse output and the parameters you can set to control these outputs Uses for timed pulse output include controlling camera reset and exposure controlling strobe lighting operating plungers on an assembly line and communicating with PLCs You can configure the start of the pulse output generation to occur from softwa...

Page 17: ...then generates one pulse and rearms to wait for the next trigger In either case the pulse output generation stops and resets if the pulse mode parameter is set to Stop in LabVIEW or imaqIOPulseStop in C and Visual Basic The following figure shows an output pulse when a trigger is selected Pulse Modes Each pulse generator has a Start Single Shot and Stop mode Configure the pulse generator when in S...

Page 18: ...n be individually configured for rising or falling edge triggering Even if multiple pulse generators are using the same trigger each can have different polarities The following figure shows the output of a pulse generator configured to look for a rising edge trigger and output a high pulse with a microsecond width and delay The following figure shows how to create a high and low pulse train with a...

Page 19: ...ase B input Encoder speed is limited by the speed of the isolated inputs Each isolated input can change at a maximum rate of 100 kHz making the maximum encoder rate 400 000 counts s The quadrature encoder can also be used as a timebase for the pulse generation delay The following figure shows a rising edge trigger and a low pulse with a quadrature encoder delay and a microsecond width Product Sele...

Page 20: ...as a latch it can be used as an extra bit of data Note In Vision Builder AI ISO Input 5 is always designated as a latch Table 2 3 lists the product selection ports General Purpose I O General purpose inputs and outputs are available as both TTL and isolated connections The software running on the NI 8254R can read the inputs and drive the outputs high or low at any time General Purpose Inputs The ...

Page 21: ...recise timing An example of using general purpose outputs is driving a relay that turns on an Inspection in Progress light for an operator to see while the inspection sequence is running I O for Fault Conditions The NI 8254R recognizes the following fault conditions External shutdown when Shutdown mode is enabled Watchdog timer expiration In the event of a fault condition the behavior of the NI 82...

Page 22: ... 8254R and take action if the software is unresponsive The millisecond counter on the watchdog timer is configurable up to 65 534 ms in 1 ms increments before it expires Configure the watchdog timer to take one of the following actions when it expires Caution Use the Indicator Only option only to test the watchdog timer If software becomes unresponsive it cannot be relied upon to send notification...

Page 23: ...ted Input to a Sourcing Output Device You can wire an isolated input to a sourcing output device as shown in the following figure Refer to the NI PCI 8254R Quick Start Guide for switching thresholds and current requirements Caution Do not apply a voltage greater than 30 VDC to the isolated inputs Doing so could damage the NI 8254R The following figure shows an example of connecting an isolated inp...

Page 24: ...n Isolated Output to an External Load The digital output circuit sources current to external loads as shown in the following figure Caution Do not draw more than 100 mA from 24 V or 30 V isolated outputs Do not draw more than 50 mA from 5 V isolated outputs Digital Output V C Vcc NI 8254R Load ...

Page 25: ... voltage can damage the outputs and the power supply To limit flyback voltages at the inductive load install a flyback diode across the load Mount the flyback diode as close to the load as possible Use this protection method if you connect any of the isolated outputs on the NI 8254R to an inductive load The following figure shows an example of using an external flyback diode to protect inductive l...

Page 26: ...al signals to the 44 pin I O D SUB connector The following figure shows connections to the 44 pin D SUB connector that minimize transmission line effects When connecting to TTL inputs on the NI 8254R match the output impedance of the transmitting device to the characteristic impedance of the cable For example if the cable characteristic impedance is 118 Ω make Rs equal to 118 Ω as shown in the fig...

Page 27: ...nual 3 Signal Connections The following diagram shows the connectors on the NI 8254R device 1 IEEE 1394a Connector 2 IEEE 1394a Connector 3 2 Position Isolated Outputs Power Connector 4 Digital I O Connector NI PCI 8254R IEEE 1394 V C 5 30V DIGITAL I O 1 2 3 4 ...

Page 28: ...y 5 to 30 VDC for the NI 8254R device The C terminal provides the common mode signal for the NI 8254R device Figure 3 1 illustrates the isolated outputs power connector on the NI 8254R device Figure 3 1 NI 8254R Isolated Power Connector Table 3 1 NI 8254R Connector Functions Peripheral Connector Function Isolated Output Power 2 position isolated outputs power connector Power for isolated outputs I...

Page 29: ...vailable on this connector includes 2 TTL inputs 9 TTL outputs 13 isolated inputs and 4 isolated outputs For easy connection to the digital I O connector use the National Instruments digital I O cable and the NI Vision I O Terminal Block and Prototyping Accessory Note The accessories available for use with the NI 8254R do not provide access to all available I O on the NI 8254R device To access thi...

Page 30: ...he 44 pin D SUB connector Do not draw more than 100 mA from 24 V or 30 V isolated outputs Do not draw more than 50 mA from 5 V isolated outputs Table 3 3 Signal Connections 44 Pin D SUB on NI 8255R Device Pin Number 37 PinTerminal Block Number Signal Name Primary Function Alternate Function 1 1 TTL Input 0 Pulse generator trigger input Trigger Change Detector General purpose input 2 3 C Common mod...

Page 31: ...main power 9 NC TRIG 2 TTL Output 9 Pulse generator output General purpose output 10 17 Viso Isolated power 11 NC TRIG 0 ISO Input 12 Pulse generator trigger input Trigger Change Detector General purpose input 12 19 ISO Output 0 General purpose output 13 35 ISO Output 1 General purpose output 14 34 Ciso Isolated common mode signal 15 9 ISO Input 0 Input port Data 0 Table 3 3 Signal Connections Con...

Page 32: ...rpose output 20 22 C Common mode signal of the NI 8255R device main power 21 23 TTL Output 6 General purpose output 22 24 TTL Output 7 General purpose output 23 22 C Common mode signal of the NI 8255R device main power 24 NC Trig 1 TTL Output 9 Pulse generator output General purpose output 25 33 Viso Isolated power 26 34 Ciso Isolated common mode signal Table 3 3 Signal Connections Continued 44 Pi...

Page 33: ...a 3 33 16 Ciso Isolated common mode signal 34 14 ISO Input 4 Input port Data 4 35 15 ISO Input 5 Input port latch Data 5 Pulse generator trigger input 36 28 Ciso Isolated common mode signal 37 25 ISO Input 6 Quadrature encoder Phase A General purpose input 38 26 ISO Input 7 Quadrature encoder Phase B General purpose input 39 28 Ciso Isolated common mode signal Table 3 3 Signal Connections Continue...

Page 34: ...rigger Change Detector General purpose input 42 32 Ciso Isolated common mode signal 43 30 ISO Input 10 General purpose input Trigger Change Detector General purpose input 44 31 ISO Input 11 User shutdown General purpose input TRIG 0 TRIG 1 and TRIG 2 are not available on the 37 pin terminal block or the signal accessory If you need access to these signals you can get them directly from the 44 pin ...

Page 35: ...Block and Prototyping Accessory Use the NI Vision I O Terminal Block and Prototyping Accessory to troubleshoot and prototype digital I O applications for the NI 8254R the NI 8255R and the CVS 1450 Series Compact Vision System The NI Vision I O Terminal Block and Prototyping Accessory provides screw terminals for easy connections and LEDs for each signal Note TRIG 0 TRIG 1 and TRIG 2 signals are no...

Page 36: ...54R device accommodates one power supply The V terminal provides the isolated output circuitry 5 to 30 VDC for the NI 8254R device The C terminal provides the common mode signal for the NI 8254R device Table 3 4 Power Connector Terminals Terminal Description V Isolated power 5 to 30 VDC C Isolated common mode signal ...

Page 37: ...nstruments Application Engineers make sure every question receives an answer For information about other technical support options in your area visit ni com services or contact your local office at ni com contact Training and Certification Visit ni com training for self paced training eLearning virtual classrooms interactive CDs and Certification program information You also can register for instr...

Page 38: ...com calibration If you searched ni com and could not find the answers you need contact your local office or NI corporate headquarters Phone numbers for our worldwide offices are listed at the front of this manual You also can visit the Worldwide Offices section of ni com niglobal to access the branch office Web sites which provide up to date contact information support phone numbers email addresse...

Page 39: ... can respond C current The rate of flow of electric charge measured in amperes D D SUB A serial connector DCAM Digital camera deployment machine Machine used to run the software in its final state this machine typically runs the software without an ADE in the form of an executable development machine Machine used to develop an application A development machine usually has and ADE installed on it E...

Page 40: ...he FPGA The wiring list determines how the gates are interconnected and this interconnection is performed dynamically by turning semiconductor switches on or off to enable the different connections H HDL Hardware description language An example of an HDL is VHDL a language used to design digital circuitry hot swapping The act of removing or swapping a device when the computer is still on I IEEE In...

Page 41: ...aced on the device with the signals on the tracks offset by 90 degrees from each other This makes it possible to detect the direction of the motion R RIO Reconfigurable inputs and outputs rising edge An edge trigger occurs when the trigger signal passes through a specified threshold A slope that is positive to the trigger is specified as the rising edge T trigger Any event that causes or starts so...

Page 42: ...Glossary NI PCI 8254R User Manual G 4 ni com V VDC Volts direct current voltage The electromotive force ...

Page 43: ...ations 2 12 overview 2 1 documentation conventions used in the manual v NI resources A 1 drivers NI resources A 1 E examples NI resources A 1 F FireWire 1 3 FPGA 2 1 G general purpose outputs 2 10 general purpose I O 2 9 general purpose inputs 2 9 H help technical support A 1 I I O for fault conditions 2 10 I O for normal operation 2 4 I O terminal block 3 9 IEEE 1394 1 3 camera cables 3 8 IEEE 13...

Page 44: ...nnections 3 1 software overview 1 1 start conditions 1 4 timed pulse output 2 5 trigger change detectors 2 8 trigger inputs 2 5 TTL inputs 2 2 TTL outputs 2 2 NI 8255R NI Vision Terminal Block and Prototyping Accessory 3 9 NI support and services A 1 NI Vision Assistant 1 2 NI Vision Terminal Block and Prototyping Accessory 3 9 P power connector terminals 3 10 power requirements 3 9 product select...

Page 45: ...d certification NI resources A 1 transmission line effects 2 14 trigger change detectors 2 8 trigger inputs 2 5 trigger polarity 2 7 troubleshooting NI resources A 1 TTL inputs 2 2 list of 2 2 TTL outputs 2 2 list of 2 2 W watchdog timer 2 11 Web resources A 1 wiring isolated input to sourcing output device 2 12 isolated output to external load 2 12 ...

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