0424 0424 ELECTRONIC TACHEOMETER EDM Instruments Surveying Instrument Collection Maker Nikon, Japan Model DTM-821 Serial Number 030531 Dimensions 168 x 182 x 365 mm Image Description This instrument features electronic readout of horizontal directions, zenith angles and measures distances electro-optically (to glass prism reflector). The instrument provides many onboard programs for the processing of measurements, such as resection with or without distances, for horizontal coordinates and elevations, setting out, coordinate calculations (incl. area). Data are stored on SRAM 'memory' cards (PC Card, PCMCIA Card, 128 kb, 256 kb, 512 kb 1 Mb). In the absence of a memory card, no recording is possible. The transfer to a personal computer (PC) is possible through a RS232 cable (9 pin) cable from the power supply socket on the instrument (or through a SRAM card reader attached to (or built into) a personal computer. Included is an internal PCD-RP-220E PCI-to-PC card drive unit with two card sockets compliant with 16-bit PC card standard (of 1997) with PCI-to-PC card interface board. The software provided (on 3.5 inch floppy disks) are compatible with the Windows XP operating system. Also included is a cable to an external 12V dc battery with RS232 socket at the DC-DC (12V - 9V dc) converter box and a RS232(9 pin) to RS232(9 pin) cable from the DC-DC converter to the communication port of the computer. Because of the multitude of operating options, familiarisation with the instrument takes considerable time. The weakest link of the instrument in student use was the not very robust card slot on the instrument. The use of the instrument at hand is severely limited by its inability to record data. The instrument features full keyboards in face left and face right as well as two-speed slow motion screws. The optical plummet is in the alidade, that is in the rotating part of the instrument. Sensitivity of plate level: 30"/2 mm The 'lumiguide' indicates to the fieldhand if he/she is on line with the line of sight of the instrument. This is useful in setting out work. Positioning accuracy about 6 cm at 100. EDM accuracy: ±(2 mm + 2 ppm) Single prism range: 1600 m (at sea level visibility of 20 km) Dual-Axes tilt sensor: Range ±3', setting accuracy ±1'' Incremental encoders on glass circles (diameter 88 mm) with diametrical circle reading in H and V. Least count of circle readout 1". Telescope: 158 mm long, magnification 33x, objective lens 45 mm Battery pack (on standards) BC-80 (7.2 V Ni-MH, s/n 22064) Weight of instrument with tribrach: about 5 kg Carrying case: 488 x 282 x 261 mm (4 kg), with tools, rain cover, lens cover. Data recording on 256 kb data card (MELCARD Mitsubishi SRAM Card MF3257-LCDAT01) History & comments Purchased by School in 2003. Conservation in plastic transport box Condition card slot damaged (no data recording possible), otherwise operational Remarks Boxed marked UNSW No. 11. Set includes Quick charger Q-75E (9V, 1.6A). Dates Catalogued by J. M. Rüeger in 2012. Photos by J. M. Rüeger. [ Back to Contents ]
