No external signal conditioning, critical dynamics, front-end components, or circuitry is required. The HSDC/HRDC series accepts direct field voltage synchro or resolver inputs, and converts them into real-time, accurate, natural binary digital data, available over an 8 or 16 bit selectable databus. Provided as a complete plug-in solution, accuracy and performance is assured from the field signals to the digital user. All units are shipped with printed test data.
The module package assures the user that all the high voltage components and transformers are conformally coated and safely contained in a flame retardant non-feeding encapsulated medium with a durable through hole solder mounting, for added containment and resistance to shock and vibration.
The built-in-self-test provides a continuous report for loss of reference, loss of input signal detect, over-speed, and over-acceleration.
The Forced angle test mode allows the user to exercise the converter on command (typical post power check), providing 3 separate test angles verses run mode for normal operation. The forced angle test provides benefits in both user validation, and added diagnostics checks to the users system.
The resolution is programmable 10-16 Bits wide, allowing the user to select the resolution best suited to the operating speed of any particular application.
Two tri-state enables are provided for low byte, high byte select in 8 bit databus applications, or that may be tied together for any 16 bit or greater environment, or tied to ground for continuous output used in discrete logic and display applications.
The inhibit input activates a buffered latch, and is internally synchronized to the busy, assuring that only the most recent valid data is stored and held on the outputs.
The HSDC/HRDC series are value-added whole converter solutions, designed for easy and guaranteed trouble free operation in the most demanding industrial and military applications.
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HSDC Series Transformer units feature internal Scott-T micro-transformers. These provide a true uncompromised galvanic isolation barrier between the field wired reference and signal lines, and the user power supplies, grounds and digital I/O. The use of high impedance transformer isolated inputs assure that signals are neither loaded or disturbed and prevents interaction or impediment of grounding schemes respective of any other apparatus sharing those lines.
This completely isolates the users circuitry from the all field wiring, and any other systems that may be using these signals; eliminating concerns over troublesome ground loops, separate analog grounds, differing potentials, ground interjected spikes, or ghostly field noise, that frequently cause computer system instabilities.
Unlike external transformers that require significant real-estate, and reduce converter accuracy by their inherent non-linearities, and unlike hybrid-typical transformers that suffer poor reliability because of their insufficient coil conductor size; the HSDC's/HRDC's internal micro-transformers provide a full 500VDC minimum breakdown voltage (high-pot), and the accuracy is guaranteed for the whole synchro/resolver converter system.
Package:
The complete converter including internal transformers, and requiring no external components, is provided in a standard 36 pin triple-dip package, w/std. .020 dia. pins, on .100" centers, with a low .43" H. profile. Comparable in size to non-isolated hybrids.
On systems employing functional test confirmations, the built-in forced self-test features yield potentially huge cost savings and save significant valuable real-estate that would otherwise be required of added D-S/D-R converters and isolated switching components to perform similar forced self-test (wraparound) type capabilities, commonly expected if not required of newer systems.
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Notes:
1. Pin S4 used on resolver input units only (“HRDC” Series).
2. Part number shown for reference only.
3. See separate electrical specifications drawing A6701.
The HSDC Series are high performance, transformer isolated, tracking, ratiometric; synchro/resolver to digital converters, with internal three-point-angle self test, and built-in-test; having internal solid state type two servo loops that track the absolute position displacement, real-time, providing a crisp, virtually dynamic response, very high accuracy, repeatability, and resolution that may even be programmed while in motion, from 10 to 16 bits wide.
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Because the converter employs the use of a type II servo loop, the converter tracks the input angle real-time without velocity lag error, the output data is dynamic, always fresh, and continuously available. Only a minimum recoverable lag may occur with extremely large excessive accelerations (at which point the data is valid with minimum lag and the fault output bit will be cleared to zero = fault automatically recovers).
This type II servo essentially closes its loop on the tangent expressed as the ratio of the sin/cos of the input angle, making this ratiometric conversion technique inherently insensitive to absolute amplitude and frequency variations, additionally; because the complex windings in the field mounted sensors themselves expand and contract together, though their absolute voltages may vary; the ratio of the sensor outputs preserve the ratiometric accuracy, thereby this ratio-conversion technique inherently provides the converter with automatic temperature compensation on the field mounted synchro/resolver sensor itself
A small <1LSB hysteresis is injected into the loop to assure that the data outputs are crisp, stable and jitter-free, and to assure true 1 bit monotonicity (every single bit state must be successively discernible, no jumping of bits).
Data made available to the outputs is continuously updated (tracking) without interruption; output data is stable, accurate, and always fresh up to the maximum tracking rate of the converter.
Most other synchro/resolver converters even approaching this size require numerous external components, allowing the user to purchase a mere "core" product; no front end signal conditioning, no isolation, no required critical dynamics components. The user buys essentially a "core", and must struggle with ever-compromising trimming/matching/selecting of parts, then anticipate tuning/tweaking of many external, interactive, precision, analog components; that determine functionality, accuracy, and dynamic performance.
In many cases the user needs to have entire precision analog component inventories, synchro/resolver test stations, standards, bridges, ratio-transformers, simulators, and a strong analog engineering and R&D staff just to confirm operation under multiple static and dynamic conditions. What starts out as a reasonably high accuracy converter "core" is later degraded significantly based on the users choice (and availability) of required external components, tweak-ability and measured test results. Additionally, these "core" converters need the added real-estate to accommodate the (typically over 30+) required external components.
Core converters need a analog intensive circuit board design that requires: persistence, multiple test and trim points, and the art of analog designers wizardry' respective of the converter, and the critical paths, placement, and interactive considerations of the external analog circuitry required just to make the converter work.
Entire front ends (signal conditioners) are often left out, core converters will feature only 2 volt single ended inputs while the field voltages are running with 7, 11.8 or even 90 volt signals (external front end components will degrade accuracy and may impair functionality), no isolation is provided, and external transformers occupying more real-estate than the HSDC series "whole converter" alone may be required.
The HSDC/HRDC converters are complete, isolated, "whole converter" products, No External Components are Required. No trial and error; accuracy and dynamic performance is fully tested and assured to the system level, treated more like a simpler digital component; use reasonable care in routing the signal inputs, apply power and your done. HSDC converters are fully tested under static and dynamic conditions, and printed test data with traceability is shipped with every unit.
Built-in “Forced Angle for Self-Test”
Provides Major Cost & Space Savings:
In addition to not requiring any external components, the HSDC/HRDC series is the first converter in the marketplace that also includes Built-In "Forced" Analog Self-test ability. This provides tremendous cost and real-estate savings on systems requiring power-up self test or test on command validations for confidence enhancement and diagnostics report. Conventionally; other converters would require expensive external D-S/D-R converters, relays and/or other switching circuitry, often suffering degraded reliability or compromising isolation throughout.
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BIT Output ( Built-In-Test & Signal/Ref. Loss Detect, Continuous):
Built - In - Test, Continuosly running in th backround and provided as a discrete BIT output pin. The BIT/Fault output, detects loss of AC reference input, loss of signal (to within 100LSB's, +500Usec.), exceeding maximum tracking rate (Overspeed), major over-acceleration (as experienced and to monitor large step inpu
ts typical of hard switching of synchro signals and using "large step Forced Angle for self test), and converter tracking failures.
The Forced Angle test features on these converters even help to validate the BIT output function is operational, providing added levels of assured system "operational" verification typically performed during post-power self-test routines.
The converter resolution is programmable, to accommodate the highest resolution available respective of the maximum operating speed of the particular application.
The resolution is programmable for 10, 12, 14, or 16 Bits per 360 degree input (1 part in 65,536), each resolution gradient representing typically 4 times the maximum tracking speed of the next. 
This allows the user to position with very tight precision at slow speeds, and still be able to report accurate real-time data while slewing at very high speeds. A simple 2 bit command input (P1 &P2) allow the user to program the resolution from 10 to 16 bits, or, jumper these inputs respective of the resolution desired for the application at hand.
User circuitry may be employed to program a lower 10 bit resolution when slewing a very high speeds, and increase the resolution upward towards 16 bits when running at lower operating speeds.
Because the Data is MSB left aligned, the user may configure his program to expect 16 bit resolution always, for complete independence from whatever resolution he is running in the actual application.
When the /INH. (Inhibit) input is cleared to zero; within 300 nsec. all data bits are latched, and data is valid to be read. Rele
ase the Inhibit line for 100 nsec. min. to assure that new data is transferred towards the buffered latch type output.
The INH line may also be used to capture real-time position data synchronized to a time stamp, camera strobe, or to capture several axis of data simultaneously on coordinated axis' control schemes.
Alternatively, the C/B (converter Busy) output may be used; it will occur as fast as the max. specified tracking rate for the resolution selected (up to every 2.0 Usec. at it's fastest rate depending on the speed of the inputs changing ), (ex. 27 RPS at 14 bits = 2.26 Usec.), it will be active = busy (logic 1=H) for nominally 300 nsec.; transfer data on the fallen edge.
For simple Display type devices, the converters will be free running and use of the inhibit or C/B line may not be required.
3-State Enables & 8 or 16 Bit Bus Control
ENH covers the 8 MSB's, ENL covers the 8 LSB's (least Significant Bits), clear to zero (logic 0VDC = L=O), data will be active on the bus within 150 nsec., for 16 Bit Bus tie both together for single line control (may also be tied to Inhibit, wait 300 nsec. for everything), if not used simply tie ENL and ENH to ground. The enable lines must be high for 40 nsec. min. to assure the outputs are all turned off of the bus.
To download HSDC HRDC series data sheet click on image at left. Note: Acrobat Reader is needed to view and print the data sheet PDF file.Older versions of the Acrobat reader may be unable to read some of the files. Click here for this free download.
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HSDC & HRDC Series are Miniature, Tracking Synchro and Resolver to Digital Converters with programmable resolution, 8/16 Bit data bus controls, continuous Built-In Self-Test report, and forced angle test modes used for functional validations on command.
Models are available with either low cost differential inputs, or internally transformer isolated inputs for the most demanding industrial and military applications.
