Nikon DTM-800 vs. DTM-801
The DTM-800 series total station was upgraded to the DTM-801 series some time between June 2000 and December 2000. The upgrade seems to be very minor, with only the EDM specs showing any change, albeit small. I initially suspected the primary reason for the change was to rebrand the instrument with what was to become Nikon's trademark turquoise colour scheme, but from looking at photos of the instruments, it's apparent that the height scope portion of the instrument was decreased between the two models, so there was a significant repackaging that took place.
Information on the DTM-801 series is quite scarce, the DTM-800 even more so. There is a good quality spec sheet for the DTM-801 series kicking around the internet, but I wasn't sure how that applied to the DTM-800 series. The following table was re-constructed from archive.org snapshots of this URL:
http://www.nikon.co.jp/survey-e/dtm-800/specs.htm
| Feature | DTM-850 | DTM-830 | DTM-820 | DTM-851 | DTM-831 | DTM-821 | |
|---|---|---|---|---|---|---|---|
| Telescope | |||||||
| Magnification | 30x (18x, 36x with optional eyepiece) | 33x (21x, 41x with optional eyepiece) | |||||
| Field of view | 1°20' (2.3 m at 100 m / 2.3 ft. at 100 ft.) | ||||||
| Resolving power | 2.5" | ||||||
| Angle measurement | |||||||
| Reading system | Photoelectric incremental encoder (Diametrical detection for H / V circles) |
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| Minimum display increment (360°) | 0.5" / 1" | 1" / 5" |
0.5" / 1" | 1" / 5" | |||
| Minimum display increment (400 G) | 0.1 mgon / 0.2 mgon | 0.2 mgon / 1mgon | 0.1 mgon / 0.2 mgon | 0.2 mgon / 1mgon | |||
| Minimum display increment (MIL6000 / MIL6400) | 0.005 MIL / 0.02 MIL | 0.005 MIL / 0.02 MIL | 0.002 MIL / 0.005 MIL | 0.005 MIL / 0.02 MIL | |||
| DIN 18723 accuracy | 1" / 0.2 mgon | 2" / 0.5 mgon | 3" / 1 mgon | 1" / 0.3 mgon | 2" / 0.5 mgon | 3" / 1 mgon | |
| Tilt sensor | |||||||
| Type | Dual-axis | ||||||
| Compensation range | ± 3' | ||||||
| Distance measurement | |||||||
| Range with Nikon prisms | Under normal atmospheric conditions (ordinary haze with visibility about 20 km / 12.5 miles) |
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| With reflector sheet | Not Specified | 5-100m/16.4-328.1 ft. | |||||
| With mini prism | Not Specified | 1100m/3600 ft. | |||||
| With single prism | 2,400 m / 7,900 ft. | 2,200 m / 7,200 ft. | 1,600 m / 5,300 ft. | 2,400 m / 7,900 ft. | 2,200 m / 7,200 ft. | 1,600 m / 5,300 ft. | |
| With triple prism | 3,100 m / 10,200 ft. | 2,900 m / 9,500 ft. | 2,300 m / 7,600 ft. | 3,100 m / 10,200 ft. | 2,900 m / 9,500 ft. | 2,300 m / 7,600 ft. | |
| With nine prisms | 3,700 m / 12,100 ft. | 3,600 m / 11,800 ft. | 3,000 m / 9,800 ft. | 3,700 m / 12,100 ft. | 3,600 m / 11,800 ft. | 3,000 m / 9,800 ft. | |
| Under good atmospheric conditions (no haze with visibility over 40 km / 25 miles) |
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| With reflector sheet | Not Specified | 5-100m/16.4-328.1 ft. | |||||
| With mini prism | Not Specified | 950m/3100 ft. | |||||
| With single prism | 2,700 m / 8,900 ft. | 2,500 m / 8,200 ft. | 2,000 m / 6,600 ft. | 2,700 m / 8,900 ft. | 2,500 m / 8,200 ft. | 2,000 m / 6,600 ft. | |
| With triple prism | 3,800 m / 11,800 ft. | 3,300 m / 10,800 ft. | 2,800 m / 9,200 ft. | 3,600 m / 11,800 ft. | 3,300 m / 10,800 ft. | 2,800 m / 9,200 ft. | |
| With nine prisms | 4,400 m / 14,400 ft. | 4,200 m / 13,800 ft. | 3,500 m / 11,500 ft. | 4,400 m / 14,400 ft. | 4,200 m / 13,800 ft. | 3,500 m / 11,500 ft. | |
| Accuracy | |||||||
| PMSR mode | ±(2 + 2ppm x D)mm at -10°C ~ +40°C / +14°F ~ +104°F ±(2 + 3ppm x D)mm at -20°C ~ +50°C / -4°F~ +122°F |
±(3 + 3ppm x D)mm at -20°C ~ +50°C / -4°F~ +122°F |
Not Specified | ||||
| MSR mode | ±(5 + 3ppm x D)mm (within 500 m / 1,600 ft.) | ±(2 + 2ppm x D)mm m.s.e. | |||||
| TRK mode | Not Specified | ±(4 + 2ppm x D)mm m.s.e. | |||||
| Least count | |||||||
| PMSR mode | 0.2 mm / 0.001 ft. (switchable to 1mm / 0.002 ft.) | Not Specified | |||||
| MSR mode | 1 mm / 0.002 ft. | 0.1 mm / 0.0005 ft. (switchable to 1mm / 0.002 ft.) | |||||
| TRK mode | 10 mm / 0.02 ft. | 1 mm / 0.002 ft. (Switchable to 10mm/0.02ft.) | |||||
| Lumi-Guide | |||||||
| Visible range | Over 100 m / 330 ft. | ||||||
| Display | |||||||
| Front | Graphic (256 x 80 pixel) LCD with backlight illumination 7-level adjustable with 20 keys | ||||||
| Rear | 16-character x 4-line, dot matrix LCD with backlight illumination with 5 keys | ||||||
| Battery | |||||||
| Battery | Clip-on Ni-MH Battery Type BC-70 | Clip-on Ni-MH Battery Type BC-80 | |||||
| Output voltage | 7.2V DC, rechargeable | ||||||
| Continuous operation time | 4.0 hrs. / approx. 4,800 measurements (angle/distance measurements) 6.5 hrs. (angle measurement only) with BC-70 | 5.0 hrs. / approx. 15000 measurements (angle/distance measurements) 7.5 hrs. (angle measurement only) with BC-80 | |||||
| Battery charger | Q-70U / E (Q-70U for 115V, Q-70E for 220 / 240V) | ||||||
| Recharge time | 1.5 hrs. | less than 2.0 hrs. | |||||
| Discharge time | 7.5 hrs. | ||||||
| Dimensions | |||||||
| W x D x H | 188 x 168 x 365 mm / 6.5 x 6.6 x 14.4 in. | 166 x 168 x 365 mm / 6.5 x 6.6 x 14.4 in. | |||||
| Weight (approx.) | |||||||
| Main unit | 8.8 kg /18.0 lbs. (with battery BC-70) | 5.6 kg /12.3 lbs. (with battery BC-80) | |||||