T2002

I can't remember what the internal battery was (probably 12VDC), BUT all Leica instruments (that I am aware of) will take an external 12VDC input to the lemo connector on the base, all you need is the proper cables to hook to any 12VDC battery to test the instrument.

SHG

SHG

It is 12 V for the internal battery. Positive terminal is on the left. There's an eBay seller who makes an internal battery pack for the T2002 and similar units---the pictures tell the tale with regard to the polarity and voltage: red wire on the left, with 10 NiMH cells at 1.2 V each, so 12 V total. I have no experience with this battery pack (it's a bit pricey); for my theodolites, power is supplied via the external connector as mentioned by Shelby Griggs. The pinout for that connector is +12V, no connect, ground, serial RX, and serial TX for pins 1,2,3,4,5, where pin 1 is at the top and the pin numbers advance counterclockwise when viewing the theodolite's connector (female) from the outside. (If I remember right, the serial levels are 0 V and 5 V, not RS-232!)

http://www.ebay.com/itm/NEW-2-6Ah-NiMH-Internal-Battery-Pack-for-Wild-Leica-T2000-T2002-T3000-w-Charger-/162353608129?

When (if?) the unit powers up, you may get errors such as "error 58". That means the internal memory-backup lithium cell has discharged and will need to be replaced. I've done that, and it's reasonably straightforward. If necessary I can describe the procedure for replacing the cell and re-entering the machine calibration constants that are printed on a small white label at the top of the battery compartment. You may get lucky, though, and have everything come up with no errors and ready to turn angles.

The full service manual is available from Juerg Dedual, proprietor of the Wild Heerbrugg archive:

http://www.wild-heerbrugg.com/shop/index.php?cPath=1_3_5_29_33&MODsid=799b9fa1289303f1f0a68444ffca4db4

The service manual is apparently not listed on that page, so you'd have to email him to place an order for it.

The serial link is useful for recording data, incidentally. The raw angles, tiltmeter values (dual axis), and processed angles are all available.

Cheers,
Peter

pmonta, post: 408869, member: 10428 wrote: you may get errors such as "error 58".

Ah, I misspoke. It's "error 8c" that indicates a bad internal cell. "Error 58" is benign and just means you haven't leveled up before turning the instrument on. Use the bubble level to get it close and power on again, and "error 58" should go away, to be replaced with angle measurements. The range of the internal tiltmeter is a few arcminutes, so level has to be that good before things will start up.

Cheers,
Peter

Thanks for the responses guys! I was able to boot it up for the first time today with positive lead on the left. I am getting that code error you talked about, 8c. But once I get it up and running and cleared, it works like a charm. Is the lithium battery hard to get to?

I just used some alligator clips and a small 12v lead battery pack to test it out. I'm working on a more permanent solution I thought of. (I'm going to use a Dewalt 12v battery that should fit in the battery bay. I'll try and share some pics of this.)

It's very exciting to see this thing come alive and feel how smooth and beautifully it operates. Someone took good care of this one. I picked it up for $150. I did download that manual, thanks for the link. There's definitely a learning curve on programming it. At times, I feel like I'm working with technology from the Apollo era! Lol! The color green lends to that retro feel - but this actually makes it fun.

One last question, I think I hear a fan running. Or maybe it's just a slight hum I hear. Does the board inside have a cooling fan? I don't see any vents though.

Thanks,
Gene

Gene Pierson, post: 409228, member: 12386 wrote: One last question, I think I hear a fan running. Or maybe it's just a slight hum I hear. Does the board inside have a cooling fan? I don't see any vents though.

I think it has a gyro; but I could be wrong...

I do know that it is a finicky gun; doesn't like wind, intense sun light or thawing ground....

Glad to hear your T2002 is booting up. Here are some notes:

- As mentioned by someone else, the calibration constants need to be there to use the unit comfortably. Without them, the vertical angles are likely to be way off (by something like 45 degrees), and you'll be unable to complete the user-level touchups like vertical and horizontal collimation, tiltmeter bias, and trunnion axis. I'll do a separate post on how to enter them (you'll want to take a snapshot of the white label on the inside top of the battery compartment). Let me also check if the presence of a battery-compartment battery is enough to keep the memory alive even if the internal lithium cell is flat.

- The humming or fan-like noise is probably the small motors that spin the angle-encoder wheels. There is one motor for horizontal and one for vertical. This type of axis system spins one disk entirely around another fixed disk for every measurement---this way any scale errors are averaged over an entire revolution. It's not clear to me why this system was not continued; I believe current-generation total stations (and other systems using angular encoders) use a single disk with fixed readouts at various points on the circumference plus a correction table based on calibration. I suppose it's less mechanically complex and perhaps cheaper.

- Internal lithium cell: yes, it is on the CPU board, the innermost of the two boards on the non-battery-compartment side, so both boards must be removed and connectors disconnected. It's a coin cell with leads soldered into holes on the board. It's best to use two soldering irons, one for each lead, then press on the leads to walk the cell out of the holes. Need three hands for this. Don't use hot air, don't heat the cell unduly, don't put lots of mechanical stress on the cell. Clean the holes with flux and solder wick and isopropanol to get them back into pristine shape to accept the new cell. I used the Tadiran TL-5186 as a replacement; it's available from Digi-Key.

- There are two manuals available, a user manual and a service manual. The service manual has things like electrical schematics, disassembly instructions with pictures, and instructions on how to re-derive the calibration constants after any servicing of the mechanical physics package.

Cheers,
Peter

If you're using the T2002 to teach trigonometry, there's a very nice web page on theodolite errors and adjustments from a math teacher who was a surveying technician in a previous life:

http://whistleralley.com/surveying/

Great diagrams.

Cheers,
Peter

pmonta, post: 409724, member: 10428 wrote: This type of axis system spins one disk entirely around another fixed disk for every measurement---this way any scale errors are averaged over an entire revolution. It's not clear to me why this system was not continued; I believe current-generation total stations (and other systems using angular encoders) use a single disk with fixed readouts at various points on the circumference plus a correction table based on calibration. I suppose it's less mechanically complex and perhaps cheaper.

It's just not needed anymore. 0.5" accuracy can be achieved with a well manufactured encoder circle and 4 evenly spaced angle reading heads. Just 2 read heads diametrically opposed will just about do it. Photo etching from a larger master circle could probably produce circles practically free of graduation errors, and eccentricity is taken care of with diametrically opposed read heads. Also static circles will accurately track moving targets. Apparently the spinning encoder won't [cite]

pmonta, post: 409724, member: 10428 wrote: I'll do a separate post on how to enter them (you'll want to take a snapshot of the white label on the inside top of the battery compartment). Let me also check if the presence of a battery-compartment battery is enough to keep the memory alive even if the internal lithium cell is flat.

Ok, the battery-compartment battery does not preserve memory across power cycles. But the good news is that it's possible to use the theodolite in its fully-calibrated state, even with a flat internal lithium cell. The trick is to keep it powered up for the entire session (let's say one day). (I have a parts-donor unit with a flat internal cell I've been using for testing.)

Here's the recipe:

1. Roughly level the theodolite using the circular bubble level and the plate level. One division on the plate level is good enough.

2. Power up.

3. When "error 8c", "error 8d", and similar appear, press [STOP]. Keep pressing [STOP] (for perhaps as many as a couple of dozen presses) until the errors and beeps go away and the display shows angles.

4. Disable the automatic shutoff: [SET] [MODE] 95 [RUN] 1 [RUN] Otherwise the theodolite will power off after 3 minutes of inactivity.

5. (optional) Turn on the LCD illuminator for better visibility: [SEARCHLIGHT] (same as the 8 key)

6. Set preferred angle units: [SET] [MODE] 40 [RUN] 4 [RUN] (for degress, minutes, seconds, tenths of seconds)

7. Enter calibration constants from the white paper label stuck to the top of the battery compartment. My label reads:

Instr. : 336077
L-Fakt. : 0.984655
Q-Fakt. : 0.988346
L-Trans. : 0.0017
Q-Trans. : 0.0059
V-Temp. :-0.00012
L-Temp. :-0.00022
Q-Temp. :-0.00023
H-Temp. : 0.00006

The first line is merely the serial number. So to enter these constants, the service manual says to do this:

[TEST] [REC] [SET] [MODE] 19 [RUN]
0.984655 [RUN]
0.988346 [RUN]
0.0017 [RUN]
0.0059 [RUN]
0.00012 [+-] [RUN]
0.00022 [+-] [RUN]
0.00023 [+-] [RUN]
0.00006 [RUN]
[STOP]

8. Perform coarse longitudinal and transverse index calibration:

[TEST] [REC] [SET] [MODE] 18 [RUN]
(point to a mark, face 1) [RUN]
(point to the same mark, face 2) [RUN]
[RUN] [STOP]

9. Perform coarse vertical index calibration:

[TEST] [REC] [SET] [MODE] 17 [RUN]
(point to a mark, face 1) [RUN]
(point to the same mark, face 2) [RUN]
[STOP]

10. Perform "set mode 10" as given in the user's manual (vertical index and tiltmeter bias)

11. Perform "set mode 13" as given in the user's manual (horizontal collimation and tilting axis). Will need a mark with significant elevation or depression for the tilting-axis measurement ("steeple check").

12. Done! Use the theodolite as normal. Don't power off or you'll need to repeat the above steps. If the battery's capacity is say 2 Ah, battery life should be at least 12 hours.

Incidentally, when doing the service-manual routines with [TEST] [REC] [SET], the [REC] and [SET] will not be acknowledged with beeps. That's normal.

Naturally, it does seem better at some point to replace the internal cell, to avoid this ten minutes of hassle at the start of every session or day.

Let me know if anything here is wrong or ambiguous. I gather you won't really be using the theodolite for production work where accuracy is a prime concern, but it still seems useful and fun to have the thing up to its full potential. If you do want to use it in production mode, replace the internal cell, get the service manual, and go through the calibration-constant verification procedures---those will let you rederive the magic numbers on the paper label. Who knows, they may change over years or decades.

Cheers,
Peter

Conrad, post: 409926, member: 6642 wrote: Also static circles will accurately track moving targets. Apparently the spinning encoder won't [cite]

That makes sense. The spinning wheels do about 3 revs per second, which is not great for dynamics, which I'm sure is important for robots. The T2002 does acknowledge the limitation by showing only a few significant digits on the angles when slewing.

Peter, thanks for the responses and the instructions! I will give this a try. At this point I don't have anything to loose. I'll follow up soon...

pmonta, post: 410087, member: 10428 wrote: Ok, the battery-compartment battery does not preserve memory across power cycles. But the good news is that it's possible to use the theodolite in its fully-calibrated state, even with a flat internal lithium cell. The trick is to keep it powered up for the entire session (let's say one day). (I have a parts-donor unit with a flat internal cell I've been using for testing.)

Here's the recipe:

1. Roughly level the theodolite using the circular bubble level and the plate level. One division on the plate level is good enough.

2. Power up.

3. When "error 8c", "error 8d", and similar appear, press [STOP]. Keep pressing [STOP] (for perhaps as many as a couple of dozen presses) until the errors and beeps go away and the display shows angles.

4. Disable the automatic shutoff: [SET] [MODE] 95 [RUN] 1 [RUN] Otherwise the theodolite will power off after 3 minutes of inactivity.

5. (optional) Turn on the LCD illuminator for better visibility: [SEARCHLIGHT] (same as the 8 key)

6. Set preferred angle units: [SET] [MODE] 40 [RUN] 4 [RUN] (for degress, minutes, seconds, tenths of seconds)

7. Enter calibration constants from the white paper label stuck to the top of the battery compartment. My label reads:

Instr. : 336077
L-Fakt. : 0.984655
Q-Fakt. : 0.988346
L-Trans. : 0.0017
Q-Trans. : 0.0059
V-Temp. :-0.00012
L-Temp. :-0.00022
Q-Temp. :-0.00023
H-Temp. : 0.00006

The first line is merely the serial number. So to enter these constants, the service manual says to do this:

[TEST] [REC] [SET] [MODE] 19 [RUN]
0.984655 [RUN]
0.988346 [RUN]
0.0017 [RUN]
0.0059 [RUN]
0.00012 [+-] [RUN]
0.00022 [+-] [RUN]
0.00023 [+-] [RUN]
0.00006 [RUN]
[STOP]

8. Perform coarse longitudinal and transverse index calibration:

[TEST] [REC] [SET] [MODE] 18 [RUN]
(point to a mark, face 1) [RUN]
(point to the same mark, face 2) [RUN]
[RUN] [STOP]

9. Perform coarse vertical index calibration:

[TEST] [REC] [SET] [MODE] 17 [RUN]
(point to a mark, face 1) [RUN]
(point to the same mark, face 2) [RUN]
[STOP]

10. Perform "set mode 10" as given in the user's manual (vertical index and tiltmeter bias)

11. Perform "set mode 13" as given in the user's manual (horizontal collimation and tilting axis). Will need a mark with significant elevation or depression for the tilting-axis measurement ("steeple check").

12. Done! Use the theodolite as normal. Don't power off or you'll need to repeat the above steps. If the battery's capacity is say 2 Ah, battery life should be at least 12 hours.

Incidentally, when doing the service-manual routines with [TEST] [REC] [SET], the [REC] and [SET] will not be acknowledged with beeps. That's normal.

Naturally, it does seem better at some point to replace the internal cell, to avoid this ten minutes of hassle at the start of every session or day.

Let me know if anything here is wrong or ambiguous. I gather you won't really be using the theodolite for production work where accuracy is a prime concern, but it still seems useful and fun to have the thing up to its full potential. If you do want to use it in production mode, replace the internal cell, get the service manual, and go through the calibration-constant verification procedures---those will let you rederive the magic numbers on the paper label. Who knows, they may change over years or decades.

Cheers,
Peter

Peter, how do you enter the calibration constant? My theodolite is stuck at perfect zeros when I hit the 'comp' button. I'm hoping some kind of recalibration will bring it back to life again.

Chris9911, post: 431036, member: 12781 wrote: Peter, how do you enter the calibration constant? My theodolite is stuck at perfect zeros when I hit the 'comp' button. I'm hoping some kind of recalibration will bring it back to life again.

The 'comp' button should be showing you the theodolite's misleveling according to the tilt sensor on the instrument. I don't know what a reading of zero means---I think if the theodolite is too far out of level it gives you an 'error 58'. Is everything else working except for the tilt sensor? Have you entered the calibration constants from the white paper sticker?

I think it's possible to turn off the compensation---that might be the reason you're seeing zero. See the user's manual for how to enable it. It should be disabled only when working with sights near the zenith (or nadir too I suppose), which are rarely encountered in surveying.

I'd really recommend the service manual from the Wild-Heerbrugg web-site guy (you may have to email him to request the document; it wasn't listed last time I checked). It will walk you though all the calibration steps.

Cheers,
Peter

Thanks, got the service manual and all is well. Now to tackle the task of converting them over to autocollimating t3000. I think its just a barrel swapout, you don't happen to know where I can find spare parts for the autocollimating barrels, do you?