Instruction/ maintenance manual of the product DAQ-12 Omega Engineering
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INTERFACE CARDS FOR PERSONAL COMPUTERS DAQ-12 Data Acquisition Adapter For 16 bit ISA compatible machines Users Manual OMEGA ENGINEERING, INC. TEL: (203) 359-1660 One Omega Drive FAX: (203) 359-7700 P.O. Box 4047 Toll free: 1-800-826-6342 Stamford, CT 06907-4047 E-mail: das@omega.
WARRANTY/DISCLAIMER OMEGA ENGI NEERING, INC. , w arrants this unit to be free of def ects in materials and w orkmanship for a perio d of 13 mont hs from the date of purchase. OMEGA w arranty adds an ad ditional one (1) month grace period to the normal one (1 ) year pr oduct w arr anty to co ver shipping and handling time.
Declaration of Conf orm ity Manufacturer's Name: Omega Engineering, Inc. Manufacturer’s Address: One Omega Drive Stamford, CT 06907-0047 Application of Council Directive: 89/336/EEC Standards t.
OMEGAnet On-line Service: Internet e-mail: http://www.omega.com info@omega.com Servicing North America : USA : One Omega Drive, Box 4047 E-mail: info@omega.com ISO 9001 Certified Stamford, CT 06907-0047 Tel: (203) 359-1660 FAX: (203) 359-7700 Canada : 976 Bergar E-mail: info@omega.
United Kingdom : One Omega Drive, River Bend Technology Drive ISO 9002 Certified Northbank, Irlam, Manchester M44 5EX, England Tel: 44 (161) 777-6611 FAX: 44 (161) 777-6622 Toll Free in England: 0800-488-488 E-mail: info@omega.co.uk It is the policy of OM EGA to comply with al l worl dwide safety and EM C/EMI regulations that apply.
Table of Contents 29 4.2 Programming the 8254 Counter/Timer ............................ 28 4.1.9 8254 Control Word/Status Register ................................... 28 4.1.8 Multi-Function Timer Register ....................................... 28 4.
List of Figures and Tables 25 Table 4-1. DAQ-12 Address Map ............................................... 15 Table 2-3. D/A Converter Mode Selection Options ................................ 14 Table 2-2. A/D Conversion Format Examples ..............
1. Introduction The DA Q-1 2 is a high s peed dat a ac quisit ion adap ter for IBM AT a nd comp atible m ach ines off eri ng ei ght d if fer ential anal og i nput channel s with 16- bit r esol ution, two anal og output channel s with 12-b it r esoluti on and four di gi tal i nput/output lines.
1.2 DAQ-12 Specifications DACK 5, 6 , 7 DRQ 5, 6 , 7 DMA Levels: IRQ 2, 3, 4. 5, 6, 7, 10, 11, 12, 14, 15 Interrupt Levels: 0000H - FFFFH I/O Address Range: ISA 16-bit Bus Interface: 491.
2. Circuit Board Description and Configuration The ba se addres s of t he DA Q-1 2 is sele ct ed using s witch es SW1 and SW 2. The op erat ing mo de of t he DAQ-12 is co nt rolled by jump ers J1 th rough J7 , while DMA an d interru pt sele ctions ar e set with jumpe rs J8 through J 11.
The a mpli fi er stag e of the A/D conver ter circui t perf orms tw o functi ons: (1) a mpli fi es low leve l input signa ls and (2) c onv ert s this in put s ignal int o a vo lta ge ran ge acc ept able to the A/D c onve rter. Sev en ga in levels a re so ftware selec table for the a mplifie r st age of th e A/D circu it.
Table 2-1 deta ils the availa ble gain s ettin gs a nd resultin g inpu t range s for t he vario us input conf ig urations. Note that the 'gai n byte' f ie ld i n Tabl e 2- 1 is the va lue wri tten to the DAQ-12's gain control register. (* indicates unipolar mode not available with gain of ½ ).
The final stage of the A/D converter circuit is the A/D converter IC . The co nverter must be co nfigur ed for unipo lar or bipo lar input vo ltages a s sho wn in Figu re 2-3. Whe n co nfigured for uni pola r ope ration, the anal og input mul tipl ied by the gai n setti ng must b e in the r ange of 0 volts (analog ground) to +10 volts.
n/a 0000 1111 1111 1111 10 0000 0111 1111 1111 0000 1000 0000 0000 5 0000 0100 0000 0000 0000 0100 0000 0000 2.5 0000 0000 0000 0000 0000 0000 0000 0000 0 1111 1100 0000 0000 n/a -2.5 1111 1000 0000 0000 n/a -5 Code Code Bipolar Unipolar Voltage Table 2-2.
The D /A converte r channel s may al so be operated i n unipolar mode: 0 to +5 volts, or b ipol ar mo de: -5 to +5 vo lts. The ou tput m ode is selec ted us ing jump er J5 as sh own in Figu re 2-5. In addit ion , a gain sele ction jumpe r is pro vided t o sele ct an outp ut gain of 1 or 2 .
2.3 Digital Input/Output The DAQ- 12 of fer s four b its of di gi tal output and four b its of di gi tal i nput f or co ntrol/ mon ito ring o f extern al digit al dev i ce s. The four digital ou tput lines a re LS TTL co mpat ible an d will init ialize low (0 vo lts) on power-u p.
2.5 Clock Selection The D AQ-1 2 is e quipped wi th a progr ammab le cl ock ci rcui t to pr oduce d ata sampl in g rate s independ ent from the clock rate o f the host co mputer. An onboard 8254 programmabl e inte rval time r, wi th a 10 MHz clock input and ei ther tw o or thr ee cascad ed 16-b i t timer s, provi des the sa mpli ng rate.
2.5.1 Internal Clock Sampling rates for the internal clock can be calculated using the following equation: t = 100ns * [N1*N2] or f = 10MHz / [N1*N2] wher e N1 is the low 1 6-b its of the clock di vid er and N2 is the high 1 6-b its of the clock divider.
Whe n co nfigured fo r a 48-bit div ider, the first s ampling p eriod will be slightly lo nger th an the other s because the fi rst cl ock per iod is r equi red to l oad the i ni tial val ue of the multi-function timer.
When the mul ti- functi on time r is use d as a pr e-d i vid er, the fr equency of the ex ternal cl ock input may be var ied fr om DC to 10 MHz as l ong as the hi gh porti on of the cl ock is at l east 30ns and the low porti on is at least 5 0ns.
2.7 Direct Memory Access Di rect Me mory Acce ss (D MA) tra nsfe rs provi de a way of transf er ri ng da ta fr om the DAQ- 12's A/D conver ter into the persona l computer 's memory wi thout using the Central Pro cessin g Unit (C PU).
2.8 Interrupts The DAQ-12 is capable of generating an interrupt from one of four sources: 1. End of conversion signal 2. DMA terminal count 3. Multi-function timer output 4. External interrupt input The i nterrupt source is softwar e selected through the D AQ-12 contr ol word r egi ster.
3. External Connections The DAQ-12 is equipped with a high density 62-pin connector as shown in Figure 3-1. 2 - CH1+ 4 - CH2- (CH10+) 6 - CH 4+ 8 - CH5- (CH13 +) 10 - CH7+ 12 - AOUT0 14 - DOUT0 6 - DO.
CHx-, C Hx+ : Ana l o g inpu ts t o t he ana l o g to digital co nvert er. When us ing different ial input mo de, eight input ch annels are a vailable (C H0+ to C H7+).
4. Register Description and Programming The DAQ-12 uses 16 con secut ive I/O address locat ions in the range 0 to FFFFH. The c ard ut ilizes thes e addre ss es fo r the regist ers list ed in Table 4-1 . (* indicat es regis ters loca te d in 8254 counter).
INT2, INT1 and INT0 control the DAQ-12 interrupt source. INT2 INT1 INT0 DESCRIPTION 0 0 0 Interrupt disabled 1 0 0 Interrupt timer 2 1 0 1 Interrupt on terminal count 1 1 0 External interrupt 1 1 1 Interrupt on end of conversion DMAEN - enables / disables DMA.
VALID - when s et, lo gic 1 , indic ate s at le ast one da ta sam ple was los t becau se it wa s rea d by the personal computer befor e the nex t sample was conver ted. Data was l ost because the sampli ng rate w as too fa st f or the computer to acq uir e the d ata.
4.1.4 D/A Converter 0 Register An output to this re giste r cause s the lower twel ve b its of data to be conve rted to an analog output on D/A conver ter channe l 0. The f our most sig nif ica nt bi ts of d ata are i gnor ed. Thi s register is 16-bit write only.
4.2 Programming the 8254 Counter/Timer This section provides programmi ng information for the 8254 count er/timer as implemented on the DAQ-12. For more details on the 8254, consult the Intel Micro-processor and Peripheral Handbook. To program any of the counters contained in the 8254 counter/timer, three steps are required: 1.
Counter 1 - Clock rate register (high word) operating mode: 2 minimum count value: 2 configuration byte: 0 / 1 / 1 / 1 / 0 / 1 / 0 / 0 = 74H Example: Program the value 13A4H into the high word of the clock rate register.
DAQ-12 Users Manual Version 2.20 January 28, 1999 Part No. 940-0030-220.
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If you have not bought Omega Engineering DAQ-12 yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Omega Engineering DAQ-12 - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Omega Engineering DAQ-12 you will learn all the available features of the product, as well as information on its operation. The information that you get Omega Engineering DAQ-12 will certainly help you make a decision on the purchase.
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