-. analog w devices i features very low radius vector variation (transformation ratio) (:to.1%) high accuracy (:t2 arc-mins at +25c) 12- or 14.bit resolution no 5 volt power supply required mi l spec/hi rei versions available internal 1.3v a amplifiers internal transformers (40phz option) no trims or adjustments necessary applications driving control transformers driving torque receivers (with external amplifiers) servo mechanisms retransmission systems positional control general description the dsc1705 and dsc1706 are digital-to-synchro and digital- to-resolver converters capable of driving electromechanical loads of up to 1.3v a. they accept a 14- or 12-bit digital input representing angle and a reference voltage of either 60hz or 400hz, and produce a 3 wire or 4 wire output suitable for driving synchros or resolvers. the 400hz converters contain internal1.3v a amplifiers as well as output and reference transformers. the 60hz versions contain internal 1. 3 va amplifiers but require external output and reference transformers. if it is necessary to drive a load requiring more than 1. 3 va, options for both the 400hz and 60hz converters are available allowing the use of external amplifiers and transformers. radius vector one of the outstanding features of these converters is the almost negligible radius vector variation (transformation ratio). on many digital-to-synchro converters presently available, the individual sine and cosine outputs produced do not follow the exact sine and cosine laws, and depending upon angle can vary up to :t7%. this is not always important as the ratio of the sine to the cosine, i.e., the tangent, is always correct to the speci- fied accuracy of the converter. there are cases however, when driving torque receivers and certain servo control loops when this variation is unacceptable. the design of the dsc1705 and dsc1706 has reduced this variation to less than to.l%. this means that when the converters are used in closed loop servo systems, the gain of the closed loop is independent of the digital input angle, thus making reference correction unnecessary. digital- to-synchro converters dsc 1705/1706 i models available the two digital to synchro/resolver converters described in this data sheet differ primarily in the areas of resolution and accuracy as follows: model dsc1705xyz is a 14-bit converter with an overall accuracy of :t4 arc-minutes. model dsc 1 706xyz is a 12-bit converter with an overall accuracy of 18 arc-minutes. the xyz option code defines the option thus: (x) signifies the operating temperature range, (y) signifies the reference frequency, (z) signifies the output and the reference voltages, whether the output is in ~ynchro or resolver format and whether external transformers are required. ii rhi 53 scott tee trans- formers refer- ence trans. formers msb " / oigital input wi principle of operation functional diagram, dsc170s and dsc1706 the principle of operation of the converters described in this data sheet is shown in the diagram above. obsolete
model accuracy. resolution input code dsc170s dsc1706 :1:4 arc-minutes 14 bits (llsb = 1.3 arc-minutes) 14-bits natural parallel binary with msb = 180 :t8 arc-minutes 12 bits (llsb = 5.3 arc-minutes) 12-bits natural parallel binary with msb = 180 reference voltage input with internal transformers . low level high level external transformer options2 reference frequency reference input impedance with internal transformers low level . high level external transformer options2 digital in,put (ttl compatible) output voltage and format with internal1ransformers low level high level external :transformer options3 load capability short circuit protection output settling tlme4 radius vector variation (transformation ratio) internal transformer isolation power supplies voltage current. (a) no load (b) full load mean warm-up time operating temperature range storage temperature range size weight mean time between failures (mtbf) calculated 26v rms 115v rms 4v rms 60hz or 400hz . . . . 20kq 200kq lokq lttl load . . . . notes .specifications same as dsc1705. i accuracy applies over the full operating temperature range of the option and for: (a) :1:10% reference frequency and amplitude variation. (b) 10% harmonic distortion on the reference. (c) :t5% power supply variation. (d) any balanced load from no load to full load. 2 refers to input to converter and not to external transformers. 3 refers to output from internal converter amplifiers and not from external transformers. 4 dependent upon option and load conditions. specifications subject to change without notice. vol. ii, 13-10 synchro & resolver converters 11.8v rms line-to-line synchro or resolver . 90v rms line-o-line synehro or resolver . 7v rms sine and cosine . 1.3va . contlduous for 5 minutes . . 50/js for 180 step to.1% max sine and cosine . 500v de . t15v de :1:5% . 95ma per line . 225ma per line . lsee to full accuracy . 0 to +700c standard . -55c to +105c extended . -55c to +125c . 3.125" x 2.625" x 0.8" . (79.4mm x 66.7mm x 20.3mm) . 8 ounces (224 grams) max . 150,000 hours . obsolete
i connecting the converter iq..ohz options. all these converters contain internal output md reference transformers. the digital input should be connected to pins "1" through "12" on the dsc1706 and pins "1" through "14" on the dsc1705, noting that pin "1" is the most significant bit (msb). "s 1 ", "s2" and "s 3" should be connected to the appropriate inputs on the synchro being driven. ("s4" is used also when connection is mad~ to a resolver). the reference should be connected to "rhi" and "rlo" ensuring that the phase is correct. "gnd" is the common for both power supplies and digital inputs. 60hz options. for 60hz operation, an external transformer, stm1679 is required. the power supplies and digital input should be connected as for the 400hz version. the stm1679 transformer should have its pins "sin", "cos" and "v" connected to the equivalent pins on the converter. the "gnd(sig)" and "gnd(ref)"should both be connected to "gnd" on the converter. the outputs to the load should be taken from "sl", "s2" and "s3" on the stm1679 transformer ("s4" also in the case of a resolver). the reference input should be made to "rhi" and "rlo" on the stm1679. stm1679 014 0 0 0 0 0 0 0 0 0 0 0 0 01 dsc v \ 60hz connection to a control transformer (diagram shows bottom view of modules) operation with external amplifiers or transformer other than stm1679 for certain applications, the power output required by the load will be greater than the l.3v a supplied by the internal amplifiers. thus external amplifiers and transformers will be needed. products offered to fulfu11 this requirement are: spa1695 - dual 5va amplifier stm1696 - 5va output and reference transformers (400hz) stm1697 - 5v a output and reference transformers (60hz) . . . if you have a requirement for such produ~ts please reql,lest converter outline dimensions and pin connection diagram dimensions shown in inches and (mm). i" 2.825 188.7) . i 'i :l 0.8 120.3) ..l pins 0.040"'0.ooi"dia. 0.2 (5.1/ u bra". hard gold plated. ~ t--- 2.2155.4) 1 i-- 2.2155.41 1 t 3.125 ..l ~ lo 2 ~ 1 (79.4) r . 1 v 1 0.263(6.71 hi (msb) (msb) t top view --i i-- 0.2 grid top view -i i- 0.2 grid 16.081 (6.08) converter with internal converter reouiring transformers external transformers note 54 present on resolver option only note diagrams above show dsc1706. dsc1706 does not have pins "13" and "14". mating socket: cambion 450-3388-01-03 transformer (stm1679) outline dimensions and pin connection diagram dimensions shown in inches and (mm). l- t 1.8 i -1 . 4.51114.31 58 a: q z ~ m3 fixing x 0.26 (6.3) deep in 4 positions bottom view pin dia. 0.040 t o.ooidia. brass. 'hard gold plate. l 0.26 1(8.41 1.6 ~ 's4 pin present for resolver option only bit weight table weight in degrees 180.0000 90.0000 45.0000 22.5000 11.2500 5.6250 2.8125 1.4063 0.7031 0.3516 0.1758 0.0879 0.0439 0 o??o bit number 1 (msb) 2 3 4 5 6 7 8 9 10 11 12 (lsb for dsc1706) 13 . a " <"" _- """""'1"in"" 14 13 - 12 54 11 s3 10 s2 9 si 8 +16 7 gnd 6 6 -16 4 3 14 13 12 11 sin 10 co 9 i 8 +16 7 gn,d 5 i 6 -< -1 4 i i 3 obsolete
wading the dsc's with control transformers (ct's) the most common device to be driven by digital to synchro converters is the control transformer (ct) the minimum power required to drive a ct can be expressed as: v2 3 (va) = tz1 . 4 so where v is the line to line voltage and zso is the impedance between one input terminal and the other two shorted to- gether with the rotor open circuit. (zso = rso + j xso) for example, if a ct has a zso of 700 + j 4900 and a line to ' line voltage of 90 volts, then: i zso i = j 7002 + 49002 = 4950 ohms 902 3 and (va) = 4950 '"4 = 1.23va tuning ct wads the load can be reduced by tuning the output with 3 capacitors as shown below. 01' 0 0 0 0 0 0 0 0 0 0 0 0 01 dsc rlo rh. capacitor connection for tuning ct's c should be equal to: xso 2w (rso 2 + xso 2) the power required after tuning will be: r (va) untuned x z so so therefore in the above example the capacitor value should be: 4900 = 40nf 2 x 21t x 400 (245 x 105) and the power required after tuning will be: 700 1.23 x 49s0 =0.17va note allowance should always be made for tolerances in the ct windings, capacitors and fre9uency. , - ,- ---c- ' 1 practical considerations of tuning ct wads' 1. th?apadto" u",d "ttd not be of high tole"",,. 20% ; , is sufficient." 2. three capacitors must be used, one across si and s2, one across si and 53 and one across s2 and s3.' 3. voltage working and type of capacitors should be as follows: ll.8v line-to-line, options: is volt ac working or greater,non-polarized tantalum type. 90v line-to-line options: ' 100 volt ac working or greater, for example, low k c-eramic types. 4. for tuning resolver loads, two capacitors only are required, one connected between si and s3 and the other connected between s2 and s4. control differential transmitters (cdx's) the loading on a dsc of these devices can be considered in a similar way to that of ct's. however becasue a ct normally follows a cdx, the effective z will need to be calculated. this value will normally be between 66% and 80% of the zso quoted for the cdx. torque receivers (tr's) torque receivers are mor~ difficult devices to drive than ct's and cdx's, and in general external amplifiers and transformers will be necessary. however, because of the lack of radius vector variation, the dsc170s and dsc1706 are far more suited to driving tr's than converters with a variation of 1:7%. for a deviation of an angle 8, the drive current required will be:, 2 . v . sin! 2 izss i points to be observed are: (a) the tr should not be allowed to lock up. (b) a phase lead equal to that specified for the tr should be introduced into the reference input to the dsc. (c) the reference should always be present on the tr and the converter. (d) the dsc output voltage should be matched exactly to the voltage requirements of thetr. cautions (a) do not connect a llsv reference to a 26v converter. (b) do not reverse the power supplies. (c) do not connect the reference to any other pins except "rhi" and "rlo ". ordering information when ordering, the converter part numbers should be suffixed by an option code in order to fully define the item. all standard options and their appropriate option codes are listed below. note: 1. for 12-bit resolution, substitute dsc1706 in place of dsc170s in the above. 2. for options not shown above, consult the factory. vol. i/, 13-12 synchro & resolver converters line-to- line operating output voltage reference reference part number! resolution temp. range and format voltage frequency dsci70ss11 14 bits 0 to +70oc 11.8v svnchro 26v 400hz dsc170ss12 14 bits 0 to +70uc 90.0v svnchro llsv 400hz dsci70s611 14 bits -ssuc to +10suc 11.8v svnchro 26v 400hz dsc170s612 14 bits -ssuc to +10suc 90.0v svnchro llsv 400hz drc170ss 18 14 bits 0 to +70 c 11.8v resolver 26v 400hz drc170s618 14 bits -sswc to +10swc 11.8v resolver 26v 400hz dsc170ss07 and stm1679522 14 bits 0 to +70uc 90.0v synchro llsv 60hz dsc1705607 and stm1679622 14 bits -ss c to +10s c 90.0v synchro l1sv 60hz obsolete
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