~ ,. analog woevices preliminary technical data features ac line powered bright seven-segment gas-discharge display floating input: >100db cmrr, 300v rms cmv nmr: >60db @ 50 or 60hz :1:0.005%r :1:50,uv :1:1 digit max error auto-zero correction optional ratiometric operation versatile data output options - dtl!ttl!cmos/pmos compatible applica tions accurate measurements in noisy electrical environments high accuracy readl!ts for test equipment, process control instrumentation, and analytical and scientific instruments , analog devices' ad2008 is a 4'12 digit ac line powered dpm designed for making high accuracy measurements in adverse electrical environments. the ad2008 measures bipolar voltages with a full scale range of :1:1.9999v and an accuracy of :1:0.005% reading :1:50,uv::':1 digit. the fujl floating, opto-isolated input section provides >100db of common mode noise rejection at common mode voltages up to 300v rms even with control signals and optional data outputs connected. in addition, the dual slope integrating conversion technique allows >60db of normal mode noise rejection at 50 or 60hz without filtering. large, bright, easily read display the ad2008 presents a visual readout on large 0.55 inch (l4mm) beckman seven-segment gas-discharge displays. these displays are easily rcad at distances up to 50 feet (15 meters) and over viewing angles of 1300 in all ambient lighting condi- tions. four decimal points are externally programmable. con- trols are also available for display testing by illuminating all display segments, and independently blanking either the polarity sign or the entire display. the display lens is color matched to the gas discharge display. the lens has a non-glare, scratch-resistant finish and is easily marked with company logo or measurement units. versatile data output options the ad2008 uses a mos/lsi integrated circuit that provides 4'12 decades of counters and latches with considerable savings in size and power consumption. the data from this chip is provided in a character serial format, one decade at a time, which is used to multiplex the display. since this data is not tj i nformation furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use; nor for any infringements of patents or other rights of third parties which may result from its use. no license is granted by implica- tion or otherwise under any patent or patent rights of analog devices. 4y2 digit ac powered dpm with beckman displays easily interfaced to other data devices, two extra cost options are available for applications requiring bcd data interfacing. the ad2008/b provides full parallel latched bcd data for 4'12 digits, overload and polarity. the ad2006/x provides a pulse train output and a polarity output, and the data must be counted external to the dpm. to extend application versatility, digital data output options are compatible to all dtl/ttl/ cmos/pmos logic systems. full details on the data output options are given in the speci- fications and timing diagram (figure 2). the ad2008 nor- mally provides 2.5 conversions per second. externally trig- gered rates up to 5 conversions per second or automatic re- cycling at 5-10 conversions per second are also possible. optional ratiometric operation the ad2008/r option allows the dpm to be used to measure the ratio of two input voltages. this is very useful when measuring with a transducer whose output is dependent on its excitation voltage. the dpm measures the ratio of the two voltages and thereby compensates for any variations caused by instability in the excitation voltage. both the analog input and the external reference input are floating. for operation in the ratiometric mode, the ad2008/r is supplied without internal references; both positive and negative references must be sup- plied externally. (continued on page 3) route 1 industrial park; p.o. box 280; norwood, mass. 02062 tel: 617/329-4700 twx: 710/394-6577 west coast tel: 213/595-1783 mid-west tel: 312/297-8710 obsolete
,pecifica tions (typical @ +25c and nominal line voltage unless otherwise specified) splay output . beckman seven-segment gas discharge-displays, 0.55" (14mm) high, for four data digits, 100% overrange and polarity indications. . overload indicated by center segment dashes, polarity remains valid. . decimal points selectable at input connector. . polarity sign blanking . display blanking . display test naloginput . full scale range - :t1.9999v . automatic polarity . automatic zero . input impedance: >109 d, shunted with 10pf . bias current: -vref ;;?-1.3v for rated accuracy . reference input impedance: >109 d, shunted with lopf . bias current: \!. ,\iode i{ejection . >(,ojb at 50 or 60hz o\t\io'\; ,\101)1- re iection . >}()()db ,,'jeh ho)kn inbalance, dv cm/dt <106v/sec (].i) x ]()' \'llz) (i.e., 160v cmv @ 1khz) :o.\i.\io,\; \to!)1 \'oltaci': . 3()()\' i{.\t<, ,jj(,!'i,\!?)"ii{()i"i(,'\;..\l<' i,,!,.." . 1 "t'., i.n'c, in l t'j l inputs: o~!.ogic "()" <+o.8v +2.0 ~logic "1" <+5v 'j fi~~n!llold input: ()~logic "0" ~+l.sv *3.5\' ~f.()gic "i" ~+sv ,..lllllput, aft: it'i l load) . display segment test. dtllttl compatible. logic "0" or grounding activates all display segments except decimal points. logic "1" or open circuit for normal operation. after a display test has occurred, the display ~ nd outpul data will not be valid until a new conversion is completed. . display blank. dtllttl compatible. logic "0" or grounding blanks the entire display including the decimal points. logic "i" or open circuit for normal operation. display blanking has no effect on output data and the display is valid immediately upon removal of a blanking signal. . polarity sign blank. dtllttl compatible, logic "0" or grounding blanks the polarity sign indication: logic" i" or open circuit for normal operation. polarity sign blanking has no effect on output data and the polarity sign is valid immediately upon removal of the blanking signal. . decimal points: grounding the appropriate pin illumin- ates the desired decimal point. open circuit turns the decimal point off. external drive circuitry must with- stand 200v when decimal points are turned off. . external trigger/hold, dtllttlicmos/pmos compati- ble. open circuit on this line allows the dpm to convert at a rate of 2.5 conversions per second under control of its internal clock, logic "0" on this line will inhibit any further conversions but allow completion of any con- version in process. a positive pulse on this line will trigger a new conversion provided no conversion is in process. the pulse width must be at least 10llsec, but not wider than one conversion period to prevent multiple conversions. the actual conversion begins approximately lolls after the leading edge of the trigger pulse. applying a constant logic" 1" or connecting this input to the +5 v output will cause the dpm to operate in a maximum rate automatic recycle mode, converting at a rate of 5-10 con- versions per second, depending on input voltage. data outputs . logic levels: . . ov . conversion time . 200ms for full scale input, 320ms max for overload con- version (2 50ms for versions optimized for 50hz opera- tion, 400ms max for overload) conversion rate . internal trigger: 2.5 conversions per second . external trigger: 5 conversions per second maximum . auto recycle mode: 5-10 conversionspersecond,de- pending on input voltage . hold and read on command externally available power outputs . +5v @ 50ma maximum power input . ac line, 47 to 440hz, 4 watts max. options for all common line voltages are available, see ordering guide. size . 4.18"w x 1.93"h x 5.19"d 006 x 49 x 132mm) 5.83" 048mm) max. to rear of connector weight . 23 oz., 652 gm. . connectors: . pi 36 pin, 0.156 inch spacing card edge connector, viking no. 2vk 18d/1-2 or equivalent optional - order ac2610 @ $5.00 each 30 pin, 0.156 inch spacing card edge connector, viking no. 2vk 15d/1-2 or equivalent optional - order ac1501, $3.50 each . pi . p2 . p2 ordering guide pricing 1-9 100 power supply options1 ad2008 115v ac :!:10% @ 60hz ad2008/e 220v ac :!:10% @ 50hz ad2008/f5 100v ac :!:10% @ 50hz ad2008/f6 100v ac :!:10% @ 60hz ad2008/h 240v ac :!:10% @ 50hz data output options2 b (parallel bcd) x (count) $295 $195 $ 603 $ 403 $ 303 $ 203 (no cost) (no cost) ratiometric operation (r) display lens options4 lens 7 red with adi logo lens 8 red without ad! logo lens 13 amber with adi logo lens 14 amber without adi logo 1 only one power supply option may be specified on any single ad2008. 2 only one data output option may be specified. if data outputs are not needed, no option should be specified. 3 additional cost above base ptice of dpm. 4 lens 7 is supplied if no lens option is specified. specifications subject to change without notice. (continued from page 1) application versatility the high accuracy, good noise immunity, ratiometric option and versatile data output options make the ad2008 easy to integrate in many types of measurement systems. some typical applications include: . in-house test equipment for instruments and components where a bright, easily-read display, high accuracy and long term stability are needed. . digital weighing systems, using the ratiometric option fo! accurately reading the output of bridge-type transducers. the ad2008 can be calibrated easily to read out in the proper units. long term stability is a plus here, too. . analytical and scientific instrumentation where high accuracy and wide dynamic range of measurement are necessary. . process control monitoring in an industrial environment, where e-m noise and high common mode voltages are commonplace. designed and built for reliability high reliability has been designed into the ad2008. in the ad2008, the latest ic technology is utilized to minimize parts count and lower heat dissipation for cooler operation. manu- facturing processes are controlled by continuous quality - assurance inspections to insure proper workmanship and testing like every other analog devices' dpm, the ad2008 is fully tested for electronic specifications, vibration tested to 1 % aql and given one full week of failure-free burn-in before ship ment. the design, manufacturing and testing procedures at analog devices are designed to insure reliable dpm's. theory of operation the block and timing diagrams for the ad2008 arc shown in figures 1 and 2. the analog section is fully isolated using transformer isolation of the power supplies and opto-isolation of all logic signals. upon receipt of a conversion command, an auto-zero cycle removes residual zero offsets. the analog input voltage is rhen swirched to rhe integrator which ramps "up" for a constant period equal 10 3 ac line cycles. a stable refer- ence voltage of opposire polariry is then switched to the inte- grator for the "ramp down" cycle. during the ramp down period, internal clock pulses arc counted in a mos/lsi coumer. the number of clock pulses counted during rhe ramp down period is proponional to the input voltage. ar the end of con- version, rhe dara is transferred to the imernal latches of the mos chip and is ready for display. the display is multiplexed, one digir at a lime, at a rate fast enough 10 prevem any visible display flicker. if the "b" ourput data option is specified, rhe logic circuirry also transfers the data into outpur registers at rhe end of each conversion, making rhe data available for inter- facing to data output devices. the "x" data option provides a gated pulse train output during the ramp down period for counting exrernaj to the dpm. ..' applying the ad2008 scaling inputs the ad2008 is designed to measure inputs over a full scale range of 0 to :!:1.9999 volts. if inputs in other ranges nel:d to bl: measured, scaling of inpurs can easily be done by amplifying low level voltages or attenuating large voltage inpurs. if a low level signal must be amplified to be measured by rhe ad2008, the amplifier chosen must be a high grade instrumentation -3- obsolete
analog inputs hi optional external reference (note 1) - - - - - - - - - - --, i i i i i i floating : - - - ~nf'u~ - - - - -- - ~ ~ +lv internal reference -lv lo logic processor trigger & hold display blank display test sign blank ac inputs 111e power suppl y + laaab mul tlplexeo display dfgit drive bcd data data out '15v -15v +5v hv (displayi note 1 ad2008!r ratiometric option involves removal of internal reference. figure 1. ad2008 block diagram -i r-- 10", min convert 1l command n integration cycle 50ms~ ~50ms, a-looms auto ramp up ramp down: zero (input) (ref 1 !: ~ data output options timing diagrams :: " bcd option (option bi -;:- note 1 data ready ~ :j--- bcd data /////////////////// p////////////////////// ~"',""""""~ valid ---------- 1 ,---- "," ,,"""" ",," " ,"" "" "," =' polarity /.""//////////////////p/~""""""""""""""""""""""""" - - - - - - - - - - valid " clock out option (option xi ---:: note 2 data ready , 1111'"11' "'":~ - - - - - - - - - data out data valid ~"""","""""~ po l ~ ~ ~; 6 ""///////// //////'i///// ~ "'" "" """"'" ,"""""""",""'" " note 1. delay of approximatel y 5ms to allow trans- fer of bcd data into output registers note 2. delay of approximatel y 5"s to allow gating counters with oata ready signal. "","""""","1/////// //////// """-- 11111 ------ v////////// ~ ,,""'" ""'" '","f;y ij//////////// ---------- figure 2. ad2008 timing diagram amplifier or chopper amplifier with performance on a par with the dpm. attenuators, likewise, must be chosen with the dpm in mind. attenuator resistors should have tempcos of less than 15 ppm and be selected for tracking characteristics. since the bias current of the ad2008 will change with temperature, keeping the source impedance below lookd wi]! prevent a zero level shift with changes in temperature. whenever scaled inputs are necessary, remember to make the signal being transmitted to the dpm as large as possible. ampli- fication should be done close to the source, attenuation close to the dpm. this will minimize the effects of emi in noisy environments. the floating input of the ad2008 makes current measurements easy, by allowing measurements to be made at very high com- mon mode voltages. shunt resistors should be chosen with wattage ratings sufficient to prevent measurement degradation by heating. for very large currents, a four-terminal meter shunt can be used, but the tempco of the shunt should be carefully checked. ratiometric operation the optional ad2008/r measures the ratio of the analog input voltage and an external reference voltage. since the dpm ramps "up" on the analog input and "down" on the reference input, it is essential that both these voltages be stable during the conversion period to assure accurate ratiometric measurements. in the ratiometric mode, the dpm displays 104 x vin/vref. ref- erence voltages in the range of 600mv to 1.3v can be used. ref- erence voltages of both polarities are needed for proper opera- tion of the ad2008 auto-zero circuit. however, if unipolar measurements only are. necessary, only the reference voltage of the ~ite polarity of the input needs to be stable; a 1 v reference that is not noisy is acceptable for the reference voltage of the same polarity as the input. since the input of the ad2008 is fully floating, both the input and references are measured with respect to the analog low input. -4- obsolete
~ interfacing digital signals conversion rate control the external trigger/hold input is a tri-state logic circuit allowing full control of the dpm conversion rate. leaving this input open will allow the dpm to convert at the internally clocked 2.5 conversions per second rate. a logic "1" or +5v applied to this input will cause the dpm to begin a new con- version immediately (~20j.1s) after completing the previous conversion. since the conversion time depends on the input voltage, the dpm will convert at rates between 5 and 10 per second. if it is desirable to use the dpm in the auto recycle mode and have data outputs, one must use the pulse train output (option x), since insuffieient time exists between con- versions to allow loading the bcd parallel data registers (option b). if the trigger/hold input is held at logic "0" or grounded, the dpm will complete any conversion in process and hold the reading until this line is released. a positive pulse on this line (logic "0" to logic "1" and return) will initiate a new conversion within ioj.1s of the leading edge of the pulse, pro- vided no conversion is in process. when a conversion is in process, the pulse will be ignored. pulse width must be at least ioj.1s, but less than one conversion period to prevent multiple conversions. ~ parallel data output option the parallel data outputs (option b) can be interfaced to any data processing device in a conventional manner. note on the timing diagram (figure 2) that while the bcd data is updated at the end of each conversion, the polarity bit is updated after the "ramp up" period. thetefore, the data is valid after the "data ready" signal goes high, but data transfer to external devices must be completed before the polarity bit is updated (approximately looms after the status goes low again). ~ 1/ ~~~c~ting ~ ~ 4.18 (10.621 top view - r i 1.93 (49.01 i l ~ lens h zero aojust (+) zero adjust h gain adjust (+) gain adjust front view pulse train output option the pulse train output (option x) is a series of pulses de- signed to be counted external to the dpm. the timing diagram (figure 2) shows that the pulse train output is available during the ramp down period, which begins ~looms after the status line goes low. the frequency of these pulses is 200khz on units optimized for 60hz operation, 166.67khz on units for 50hz operation. external counters should count on the positive transition. since the "data ready" line does not go high until approximately 5j.1s after the last pulse, the status signal can be used to gate ripple counters without timing problems. as with the bcd data, the polarity bit is updated at the end of the ramp up period, just preceding the pulse train output. ad2008 calibration procedures warning: for the safety of personnel and interconnected equip- ment, all calibration adjustments should be made using a plastic trimming tool only. zero and gain adjustments are provided for both (+) and (-) inputs. although the ad2008 has an automatic zero correction circuitry, the zero adjustment is provided to compensate for non-linearities at very low input signal levels. this zero adjust- ment is fully calibrated in final testing and it normally will not need adjustment. zero adjustment: using a calibrated reference source, apply an input of +1 0 0j.1 v :!:i5j.1v, and adjust the (+) zero pot until the meter reads +0001. repeat the procedure for -ioj.1v :!:i5j.1v, adjusting the (-) zero pot. gain: apply an input of +1.9v :!:i5j.1v. adjust the (+) gain pot so that the dpm reads + 19000. turning the pot clockwise in- creases the reading. repeat for an input of -1.9v :!:i5j.1v, adjusting the (--) gain pot. p2. 15 pin connector ]' @ snap.in mounting block 601 r v 3.92 (99.61 \_- "1 ~ key between pins 13 & 14 p1. 18 pin connector rear view figure 3. ad2008 mechanical outline {dimensions shown in inches and {mm}} -5- zh 09 - ":)'\1/\ ot>l 0 h zh 09 - ":)'\1/\ om 0 9 zh 09 - ":)'\1/\ ool 0 9 ! ) zh 09 - ":)'\1/\ oll 0 , (1 11 zh 09 - ":)'\1/\ 9n 0 alddns 1j3mod nol.ldo '" marking to appear on hddzov top surface i<:::',\ ?-\0;;.<';', i 0.2616 @ !:/bbbb .. .... a obsolete
pl e *denotes parallel bcd data (option ubu) p2 ey count data output (option x) figure 4. ad2008 signal & pin designations compress mounting block to snap intoslot " (qj l.:: ~~ panel thickness 0.0625 to 0.125 (1.6) to (3.2) connector pl ......... . . . . . . . . . mounting block tension screw mounting instructions: 1. slide dpm through panel cutout from front of panel. 2. snap mounting block into slot on dpm sides. 3. tighten mounting block tension screws snugl v to secure dpm to panel (do not overtighten!) 4. snap lens onto front of dpm. figure 5. ad2008 mounting instructions (dimensions shown in inches and (mm)). --~- . v i' 00 i 0 - i n - n u . . . ~ |
