This page contains additional APE (Absolute Position Encoder) information.
The APE sensor (Resolver/Transductor) are embedded inside the RA/Dec shaft. They provide sufficient accuracy for TCS3. However, the TCS1 readout electronics were obsolete, and the IRTF does not have any spares. The TCS3 replaced the TCS1 readout electronics and route the APE data to the TCS3 computer system.
The TCS3 electronics will be installed along with the existing APE electronics. The pre-amp will be located near the existing pre-amps near the sensor (resolver/transductor). A new APE JBox will be mounted near the existing TCS1 APE JBox. The resolver and transductor's convert boards, and an embedded CPU board will be located inside the new JBox. The embedded CPU will perform the correlation algorithm and provide APE data via remote-procedure-calls. The power to the system is provide by the existing JBox. The APE sensor can only be attached to a single system, TCS1 or TCS3. It may be possible for the TCS3 to feed APES data to tcs1, either by using the forth hhmmss.ss ddmmss.s !START command or feeding parallel data directory to the MCC.
The correlation logic was provided by Farrand Controls. Review the vendor information directories of the TCS3 web site.
Diagram showing how the tcs3 will integrated with the tcs1 hardware: (APE_tcs1_to_tcs3_conversion.vsd)
Notes on the x86 embedded CPU and their configuation can be found at computers/embeddedx86 directory.
The source code for the APE embedded CPU is located in /home/tcs3/src/tcs3/embeddedx86/ape/
eng_data/050401_ha/. Engineering data and notes on converting Fine/Coarse position to HA.
eng_data/050615_dec/. Engineering data and notes on converting Fine/Coarse position to Dec. (Hardware not working, will take new data after hardware is fixed.).
eng_data/050621_dec/. Engineering data and notes on converting Fine/Coarse position to Dec.
misc/2004-09-lab_test - save some test data on the lab test hardware.
misc/0412_review.ppt - power point presentation for the APE review, given on 12/2004.
misc/encoder_primer.pdf A encoder primer
old - this directory contain depreciated or old documentation.