Help with Topcon DT-102 settings and RS-232 pinout

[MitchPTD]

This is the only thing I can find.   Not sure if its the same for that older DT, but I can’t find a pdf of the manual.  This is for the Dt-200 Series, which also uses 7 settings.  1 being the far right, 7 being the far left. 6 and 7 arent used.  3 sets the RS-232 to on or off.

?? Selecting mode 2
To set the instrument to selecting mode 2, turn the power ON while
pressing {V/%}.
ƒ?› Do not change the setting value (0) of unused items.
ƒ?› *1) DT240/540/540L only
Selecting mode 2
Digit
No. Items Contents Setting value = 0 Setting
value = 1
1 Press {0 SET}
once/ twice
Select number of times {0SET} is
pressed to set horizontal angle to
0.
Twice Once
2 Compass
ON/OFF
Set the compass to ON or OFF
(Vertical angle scale). OFF ON
3 RS-232
Output *1)
Set data input/output function to
ON or OFF. OFF ON
4 H Angle
Memory
Horizontal angle set can be
retained after the power is turned
off.
OFF ON
5
Tilt
correction
ON/OFF *1)
Set tilt correction to ON or OFF. OFF ON
6
7
Unused
— — —

[jonathanjo]

In case it helps someone else, just posting what I’ve found out from my day of trial and error.

Settings

When switched off, pressing R/L then Power enters settings 1.  V/% and Power enters settings 2.  There is no indication on screen which it is.  Then you press R/L, V/% or Hold buttons to move left, right, and change bits.  To save, press 0 Set, then power to switch off.

I tested all the following on the DT-102 (this table from manual for DT-110L, a very similar machine.)

The “settings of the compasses” appears to be a numbering of the vertical axis, to give +90 at zenith, -90 straight down, and 0 at both horizons.

Serial port

Serial port on the DT-102 is a socket, and your cable requires a Hirose HR10A-7P-6P plug (Series HR10A connector, 7mm plug with 6 pins).  Note that on the DT-102 the socket is mounted upside-down (the wide slot is at the bottom and text “HRS” is upside-down.)  This drawing shows the pinout as it appears looking at the socket on the theodolite.  TXD is data from the theodolite, RXD is data to the theodolite.

I used a USB serial port commonly sold as a “Cisco USB console cable” (Ebay, ?œ4), based on a “FTDI” chip.  I connected just the ground and the theodolite’s TXD (ie pins 1 and 3), as I don’t intend sending anything to the DT-102 (what could we send?)

The DT-102 only sends data when Settings 2, Digit 3 is a 1, and apparently only after the V button is pressed, and the vertical set has been done.  I’m sure other modes are possible.

The serial port sends at 1200 baud, 7 data bits, even parity.  I haven’t found any way to change this.

It sends messages at about 2 per second, in the following format:

       <0005310+0074640+****d094

Each message is followed by ETX, CR, LF (ie ASCII 3, 13, 10)

This matches the screen showing 0 deg 53 min 10 sec vertical and 7  deg 46 min 40 sec horizontal right.  Note leading zeros.

I do not know what “+****” means, perhaps a placeholder for distance (for a model with rangefinder).  My guess is that “d094” is some kind of checksum, as yet unknown.

With horizontal left, the unit transmits

       <0005310-3521320+****d093

Note minus sign for horizontal left,.

Doubtless the format will vary depending on the mode (degree, gon, mil and compass vertical mode) and perhaps many other things (min display angle?)