DAQ Signal Accessory (Demo Box)
Contents
1. Figure 4 Quadrature Encoder Pulse Trains How to Connect the Quadrature Encoder to Your Counters E Series DAQ Devices Connect phase A to the SOURCE of counter 0 Internally phase B is connected to DIO6 which is the up down line for counter 0 Do not wire the phase B terminal when using the quadrature encoder with an E Series DAQ device If you configure counter 0 for hardware up down counting counter 0 will count up when the up down line is high and count down when the up down line is low For example if counting on the rising edge of phase A as shown in Figure 4 the up down line phase B is low when the quadrature encoder is rotated clockwise and high when it is rotated counter clockwise Missed pulses could be the result of your spinning the knob too quickly or jiggling the shaft Rotate the knob slowly and do not jiggle the knob in a side to side motion The DAQ signal accessory does not incorporate anti jitter circuits but National Instruments recommends 11 the use of these circuits For more information on anti jitter circuitry see National Instruments Application Note 084 Using Quadrature Encoders with E Series DAQ boards For more information on up down counting see the AT MIO AI E Series User Manual For more information on using software with your counters see the software section of National Instruments Application Note 084 Using Quadrature Encoders with E Series DAQ boards Am9513 Based MIO Devices or Lab2. JO __ gt O Counters 4 Gate5 7 Gate1 5 Out5 8 Outi 6 Source 1 Figure 5 Quadrature Encoder Connections for Am9513 based MIO Devices Quadrature Encoder Examples For quadrature encoder examples using LabVIEW software see National Instruments FaxBack support document 4519 or download the examples from the National Instruments ftp site at ftp ftp natinst com support labview demos windows 4 0 quad encoder zip For LabWindows CVI quadrature encoder examples download from the National Instruments ftp site ftp ftp natinst com support labwindows demos cvi quad encoder zip 13 Specifications Relay Load voltage DC or rms AC 42 V max Load CULTENE ese eeccsseecesseeceesneeseeeee 200 mA max ON TESISTANCE ssoi 8 Q max 6 Q typical Leakage CUITENK essessseeerseeesneeeeneees 1 uA max POWET ON State escseecsescsneeeeeeesseeenees relay open Physical Dimensions 1 ceeessseescnseeseeecsscceeseesseceenses 12 9 by 12 9 by 6 5 cm 7 by 7 by 9 5 in Environment Operating temperature 10 to 50 C Storage temperature 0 eee 20 to 70 C Relative humidity eee 5 to 95 noncondensing
3. Using an MOV for AC Inductive Loads Figure 3 Relay Protection When Switching Inductive Loads ce Note For the flyback diode use a diode with a reverse breakdown voltage at least ten times the circuit voltage and a forward current at least as large as the load current Thermocouple and IC Temperature Sensor The standard slotted thermocouple jack on the side panel is connected internally to AI channel 4 Mating connectors type SMB are available from Omega and can use any type of thermocouple wire The IC temperature sensor wired to AI channels 0 and 5 provides cold junction compensation through software The IC sensor voltage is linearly proportional to the sensor temperature where C Volts 100 The sensor is accurate to 1 5 C For convenience AI channel 3 is tied to analog ground so you can measure and compensate for the amplifier offset cP Note Turn the noise generator off before taking thermocouple measurements For more information on thermocouples and cold junction compensation refer to National Instruments Application Note 043 Measuring Temperature with Thermocouples Noise Generator Digital Trigger Counter Timers You can use the noise generator switch on the DAQ signal accessory to induce noise on IC temperature sensor signals Using this switch you can demonstrate software techniques such as averaging to reduce the effects of noise The noise is equivalent to about 2 C and is produced by the sine
4. internal and external relay connections Solid State Relay Quick Connect Terminal on DAQ Signal Accessory Internal Schematic External Connection Figure 2 Relay Connection In the closed state the relay has a maximum resistance of 8 Q 6 Q typical and carries up to 200 mA of current In the open state the relay blocks up to 60 VDC or 30 V with 42 4 V peax with a maximum leakage current of 1 yA Isolation prevents damage to the DAQ device On power up of the DAQ device the relay default setting is open because the digital lines of the DAQ devices are in a high impedance or input state If you unplug the DAQ signal accessory the relay returns to the open state When you connect inductive loads to the solid state relay a large counter electromotive force occurs at relay switching time because of the energy stored in the inductive load These flyback voltages can severely damage the relay Limit flyback voltages at your inductive load by installing a flyback diode across your inductive load for DC loads or a metal oxide varistor MOV for AC loads To install these protective circuits see Figure 3 DAQ Signal Accessory Flyback Diode DAQ Signal Accessory MOV o e foes o j Relay Inductive Load Relay Inductive Load e V7 VDC VAC Quick Connect Terminal Quick Connect Terminal Using a Flyback Diode for DC Inductive Loads
5. wave of the function generator Adjusting the function generator frequency to about 10 kHz produces a typical noise signal on the temperature sensor output You can use the digital trigger switch to trigger acquisitions Pushing the switch creates a debounced falling edge on the EXTTRIG or PFIO TRIG1 signal line The DAQ signal accessory has connections for two counters from each DAQ device Refer to the side label of the DAQ signal accessory to determine which quick connect terminal corresponds to the counter line for your device Table 3 Counter Connections Counter MIO AI Am9513 based Lab 1200 Line E Series MIO Series Series SOURCE Counter 0 Counter 5 Counter 2 CLOCK SOURCE Counter 1 Counter 1 Counter 1 CLOCK Quadrature Encoder A 24 pulse per revolution mechanical quadrature encoder measures the position of a shaft as it rotates The DAQ signal accessory demonstrates the use of the quadrature encoder using a knob located in the upper central portion of the top panel The quadrature encoder produces two pulse train outputs corresponding to the shaft position as you rotate the knob Depending on the direction of rotation phase A leads phase B by 90 or phase B leads phase A by 90 This relationship is illustrated in Figure 4 Phase A Phase B Counter Clockwise Rotation Clockwise Rotation
6. 1200 Series Devices As shown in Figure 4 phase B is low on the falling edge of phase A when the encoder rotates in the counter clockwise direction but phase B is high when the encoder rotates in the clockwise direction Connect the quadrature encoder as shown in Figure 5 for a Am9513 based MIO device Use high level gating mode 0 on 8253 8254 counters to ensure that clockwise rotation allows only one counter to count while counter clockwise rotation allows the other counter to count Since the counters count on the falling edge of the SOURCE when the GATE is high counter 1 counts when you rotate the knob in the clockwise direction while counter 5 counts when you rotate the knob counter clockwise The difference between the counts is the total distance rotated The counters on the Lab 1200 Series devices work as stated above except counter 2 is used instead of counter 5 Missed pulses could be the result of your spinning the knob too quickly or jiggling the shaft Rotate the knob slowly and do not jiggle the knob in a side to side motion The DAQ signal accessory does not incorporate anti jitter circuits but National Instruments recommends the use of these circuits For more information on anti jitter circuitry or using software with your counters see National Instruments Application Note 084 Using Quadrature Encoders with E Series DAQ boards 12 1 Phase A Output 2 Phase B Output 3 Source 5 Relay DIO 5 200mA Max
7. 6 What You Need to Get Started To set up and use your DAQ signal accessory you will need the following DAQ signal accessory DAQ Signal Accessory User Guide Your DAQ device 16 to 22 gauge insulated wiring SH6868 or NB1 cable One of the following software packages and its documentation LabVIEW LabWindows CVI NI DAQ ComponentWorks 0 O O C O O VirtualBench LJ Your computer Some operations of the DAQ signal accessory may also require the following J Monophonic microphone LJ Thermocouple with mating connector National Instruments Documentation The following National Instruments documents contain information you may find helpful e Your DAQ device manual e Application Note 043 Measuring Temperature with Thermocouples e Application Note 084 Using Quadrature Encoders with E Series DAQ Boards e Quadrature encoder examples available by FaxBack information retrieval system document 4519 and through the National Instruments ftp site at ftp ftp natinst com Unpacking Your DAQ signal accessory is shipped in an antistatic package to prevent electrostatic damage Electrostatic discharge can damage several components on the device To avoid such damage in handling the device take the following precautions Ground yourself via a grounding strap or by holding a grounded object Touch the antistatic package to a metal part of your computer chassis before removing the DAQ sign
8. N A NATIONAL l INSTRUMENTS The Software is the Instrument DAQ SIGNAL ACCESSORY This guide describes the features of your DAQ signal accessory what you need to get started and the installation and operation of your DAQ signal accessory Introduction The DAQ signal accessory tests and demonstrates the use of National Instruments multifunction I O MIO and Lab 1200 Series data acquisition DAQ devices The DAQ signal accessory has a function generator a microphone jack four LEDs a solid state relay a thermocouple jack an integrated circuit IC temperature sensor a noise generator a digital trigger access to two counters and a 24 pulse per revolution quadrature encoder The DAQ signal accessory supports the following DAQ devices e 68 pin MIO E Series devices e 68 pin AI E Series devices e Am9513 based MIO Series devices e Lab 1200 Series devices including the SCXI 1200 Lab PC 1200 DAQPad 1200 and DAQCard 1200 The DAQ signal accessory does NOT support the following devices e PC LPM 16 and DAQCard 700 500 devices e DSP and A21xx Series devices e SCXI devices except the SCXI 1200 LabVIEW NI DAQ ComponentWorks DAQCard DAQPad SCXI and VirtualBench are trademarks of National Instruments Corporation Product and company names listed are trademarks or trade names of their respective companies 321322A 01 Copyright 1996 National Instruments Corporation All rights reserved October 199
9. al accessory from the package Remove the DAQ signal accessory from the package and inspect it for loose components or any other sign of damage Notify National Instruments if the unit appears to be damaged in any way Do NOT use a damaged DAQ signal accessory with your computer Never touch the exposed pins of connectors Installation This section explains how to connect your DAQ signal accessory to your computer Figure is the DAQ signal accessory parts locator diagram NATIONAL INSTRUMENTS Quadrature A TUU an es inne S Encoder BILL 24 Pulses rev Digital Trigger Digital Port 0 fal QOOOOs 3 2 1 0 0 Frequency Frequency Range Adjust 13kHz 1MHZz ga C 1kHz 100kHz lt 4 ae r 100Hz 10kHz Lo SA H Analog Analog Function Out In Generator obs Counters 50 pin MIO Device Diff Mode v 68 pin Device Diff Mode Lab 1200 Series Device RSE Mode A an Temp Sensor Noise Off E One Temp Sensor 5 ODIO CIOCO vce Ja Signal Accessory Ch 0 At 142 mAn Cho O 3 5 mm Mono Microphone Jack 10 Function Generator Frequency Adjust Knob 68 Pin Device Connector 11 Function Generator Frequency Range Selector Power LED Indicator 12 Noise Generator Switch Quadrature Encoder Output IC Temperature Sensor Quick Connect Terminal for R
10. ct terminals Strip insulation from the ends of the insulated wire 2 Locate the desired terminal 3 Push down on the orange tab 4 While holding down the orange tab insert the stripped end of the wire 5 Release the tab Analog Input Analog input channels and 2 are available at the quick connect terminal located in the lower central portion of the top panel Your DAQ device must be configured in bipolar mode to use the AI signal connections on the DAQ signal accessory If you are using a MIO Series device also configure the device for differential DIFF mode If you are using a Lab 1200 Series device also configure the device for nonreferenced single ended NRSE mode 5 Analog Output Analog output channels O and 1 are available at the quick connect terminal located at the lower central portion of the top panel DAQ Signal Accessory Operation This section explains how the DAQ signal accessory works Channel Connections Power Supply Table 1 lists the AI channel numbers and their connections on the DAQ signal accessory Table 1 Channel Connections IC temperature sensor Quick connect terminal Quick connect terminal Tied to analog ground Thermocouple jack Microphone jack Available for custom wiring directly on circuit board The 5 V line from the DAQ device supplies power to the DAQ signal accessory Laptops should have no problem supplying this power If the power LED on the DAQ signal access
11. elay DIO 5 Quick Connect Terminals for Function Generator Quadrature Encoder Knob Quick Connect Terminal for Al Channels 1 and 2 Digital Trigger Push Button Switch Quick Connect Terminal for AO Channels 0 and 1 Quick Connect Terminals for Counters 50 Pin MIO Device Connector Digital Port LEDs Lab 1200 Series Device Connector Figure 1 DAQ Signal Accessory Parts Locator Diagram 4 gt a 1 0 Wy Caution You should exercise electrostatic precautions including using ground straps when using the DAQ signal accessory Failure to prevent electrostatic discharge could damage the device Do NOT connect more than one DAQ device at a time Installing Your DAQ Signal Accessory Refer to Figure 1 as needed to install your DAQ signal accessory using these steps 1 Check to be sure your DAQ device and software are installed in your computer 2 Turn off your computer 3 Connect one end of your SH6868 or NB1 type cable to your DAQ device 4 Connect the other end of your SH6868 or NB1 type cable to the appropriate connector of the DAQ signal accessory Using the Quick Connect Terminals The DAQ signal accessory has quick connect terminals for analog input AJ analog output AO analog ground relay quadrature encoder output function generator and counter connections Follow these steps to use the quick conne
12. ory is not lit check the fuse on your DAQ device If the power LED is not lit and your DAQ device does not have a fuse check that your computer is powered up and your SH6868 or NB1 cable is connected Table 2 presents the DAQ signal accessory s power consumption relative to the operations you will use Table 2 Power Consumption DAQ Signal Accessory Power Usage Operations 4 LEDs circuitry 82 2 mA 4 LEDs relay circuitry 95 5 mA Function Generator Microphone LEDs Relay The function generator produces a 2 Vion peak to peak voltage sine wave and a transistor to transistor logic TTL square wave Use the function generator Frequency Range selector switch to select a frequency range The choices are 100 Hz to 10 kHz 1 to 100 kHz or 13 kHz to 1 MHz Use the Frequency Range knob to further adjust the frequency The 3 5 mm microphone jack is wired internally to AI channel 6 The jack is wired as a mono jack and you should use mono microphones You can find 1 4 in to 3 5 mm adapters at an electronic parts store Four LEDs are wired internally to digital port 0 The four LEDs use inverted logic For example driving digital input output DIO line 0 low will illuminate LED 0 Turn on a solid state relay by driving DIO line 5 low DIO line 5 is port B line 1 of the Am9513 based MIO devices This relay has no moving parts and is not subject to the limited lifetimes of electromechanical relays Figure 2 shows both the
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