Geokon 6850-7 User manual

Instruction Manual
6850-7 / 6850-8
Manual Sighting and Reading Table
No part of this instruction manual may be reproduced, by any means, without the written consent of Geokon, Inc.
The information contained herein is believed to be accurate and reliable. However, Geokon, Inc. assumes no responsibility
for errors, omissions, or misinterpretation. The information herein is subject to change without notification.
Copyright © 2017 by Geokon, Inc.
(Doc Rev Initial, 11/28/2017)

Warranty Statement
Geokon, Inc. warrants its products to be free of defects in materials and workmanship, under
normal use and service for a period of 13 months from date of purchase. If the unit should
malfunction, it must be returned to the factory for evaluation, freight prepaid. Upon examination
by Geokon, if the unit is found to be defective, it will be repaired or replaced at no charge.
However, the WARRANTY is VOID if the unit shows evidence of having been tampered with
or shows evidence of being damaged as a result of excessive corrosion or current, heat, moisture
or vibration, improper specification, misapplication, misuse or other operating conditions outside
of Geokon's control. Components which wear or which are damaged by misuse are not
warranted. This includes fuses and batteries.
Geokon manufactures scientific instruments whose misuse is potentially dangerous. The
instruments are intended to be installed and used only by qualified personnel. There are no
warranties except as stated herein. There are no other warranties, expressed or implied, including
but not limited to the implied warranties of merchantability and of fitness for a particular
purpose. Geokon, Inc. is not responsible for any damages or losses caused to other equipment,
whether direct, indirect, incidental, special or consequential which the purchaser may experience
as a result of the installation or use of the product. The buyer's sole remedy for any breach of this
agreement by Geokon, Inc. or any breach of any warranty by Geokon, Inc. shall not exceed the
purchase price paid by the purchaser to Geokon, Inc. for the unit or units, or equipment directly
affected by such breach. Under no circumstances will Geokon reimburse the claimant for loss
incurred in removing and/or reinstalling equipment.
Every precaution for accuracy has been taken in the preparation of manuals and/or software,
however, Geokon, Inc. neither assumes responsibility for any omissions or errors that may
appear nor assumes liability for any damages or losses that result from the use of the products in
accordance with the information contained in the manual or software.

TABLE of CONTENTS
1. INTRODUCTION .................................................................................................................................................. 1
2. INSTALLATION.................................................................................................................................................... 1
3. MOUNTING ........................................................................................................................................................... 2
3.1 GENERAL ............................................................................................................................................................ 2
3.2 FLOOR MOUNTING.............................................................................................................................................. 2
3.3 WALL MOUNTING............................................................................................................................................... 4
4. OPERATION.......................................................................................................................................................... 5
5. DATA REDUCTION FORMULAS FOR MANUAL SIGHTING AND READING TABLE......................... 7
FIGURES
FIGURE 1-PLANE DIMENSIONS DRAWING OF MANUAL SIGHTING AND READING TABLE ............................................. 1
FIGURE 2-KEY DIMENSIONS OF FLOOR MOUNTING BRACKET ..................................................................................... 3
FIGURE 3-SCHEMATIC DRAWING FOR FLOOR MOUNTING............................................................................................ 3
FIGURE 4-SCHEMATIC DRAWING FOR WALL MOUNTING............................................................................................. 4
FIGURE 5SCHEMATIC DRAWING OF BRACKET DIMENSIONS ......................................................................................... 5
FIGURE 6-SHOWING THE COLLIMATION PROCESS........................................................................................................ 6
FIGURE 7-SCREEN-SHOT OF THE ANDROID SOFTWARE OUTPUT.................................................................................. 6

1
1. INTRODUCTION
Models 6850-7 and 6850-8 Manual Sighting and Reading Tables is a manual measurement
device for detecting and measuring the horizontal displacement, inside a dam embankment, of a
pendulum wire relative to the station inside the dam embankment at which the sighting device is
mounted. The maximum range of the device is ±25 mm in two horizontal orthogonal directions
X and Y. The sighting device can either be secured to a wall with a bracket or mounted to a table
fixed to the floor depending on the space limitations of the station location.
The Manual Sighting and Reading Table consists of a base plate on which is mounted two steel
rule, reading scales and two sliding sighting devices. By moving the two sighting devices over
the reading scales they can both be aligned in such a way that, when looking through the hole in
each sliding device, the pendulum wire lines up with one of the front sights. In this position, the
two values on the underlying scale can be read and entered into the Pendulum Collimation
Software to yield the X and Y coordinates of the pendulum wire.
2. INSTALLATION
Figure 1 is a dimension drawing indicating the location of the mounting holes of Manual
Sighting and Reading Table. There are four mounting holes on the plate. The hole spacing is 256
mm × 95 mm (10.07 × 3.74 inches). Four stainless steel bolts are included in both metric (M8 ×
20 mm) and standard (5/16”-18 x 1.25”) sizes. Also included are four nuts, four flat washers, and
four spring washers.
Unit ： mm
Mounting holes
（place）
Line（Origin）
front sight (B）
Sliding Sighting
(A1)
Sliding Sighting
(B1)
front sight (A）
Figure 1 - Plane Dimensions Drawing of Manual Sighting and Reading Table

2
3. MOUNTING
3.1 General
The Manual Sighting and Reading Table can be mounted in two ways: floor fixation or wall
fixation.
No matter in what way it is mounted, it must be ensured that directions X and Y correspond to
the expected directions, Y being typically oriented directly Upstream/ Downstream.
The base plate must be leveled using a spirit level. For the software to work over the full range
(±25 mm in both X and Y axes), the base plate must be positioned so that the initial position of
the pendulum wire is a close to the Origin Point shown in Figure 1 as possible. (Due regard
should be given to the current position of the pendulum wire within its annual cycle of
movement due either to temperature or reservoir level).
The base Plate should be installed 1.5 to 1.6 meters above the ground and a one-meter space
should be kept free in front of the steel scales
3.2 Floor Mounting
In most cases, this mounting method can be used when the pendulum wire is far away from the
wall. When mounting this bracket, users can make adjustment in X/Y direction in order to keep
the pendulum wire close to the origin position on the base plate.
Use angle steel, (40 mm x 40 mm or 45 mm x 45 mm), to fabricate a bracket based on the
dimensions and structure shown in Figure 2.
It is recommended that the bracket should measure 296 to 306 mm wide and 300 mm deep and
its height is considered proper if operation and reading are convenient. It is recommended that
the height should be around one to one and a half meters. Where a higher bracket is needed, the
bracket can be mounted on a platform poured with concrete (refer to Figure 3). The slotted hole
in the brackets should be 50 mm long.
Except for important dimensions, users may adjust the dimensions and structure of the bracket
providing that the new dimensions do not affect mounting and operation.

3
H
Figure 2 - Key Dimensions of Floor Mounting Bracket
Figure 3 - Schematic Drawing for Floor Mounting

4
3.3 Wall Mounting
When the distance from the perpendicular to the wall ranges between 100 mm and 400 mm, the
wall fixation method can be used for mounting. Wall brackets can be provided by Geokon with
the Manual Sighting and Reading Table.
Dimension L in Figure 4 is the distance from the straight side of the base plate to the wall.
Generally, L, the distance from the plumb wire to the wall = 70 mm
Figure 4 - Schematic Drawing for Wall Mounting
At the time of mounting, consideration should be given to the distance, M, of the plumb wire
away from the wall. The bracket, as shown in Figure 5, should be designed so that M = (L + 73)
mm. Dimensions D and H depend on the distance from the plumb wire to the wall, which also
determines the width and height of the bracket. Dimension W corresponds to what is mentioned
in Section 2. The top height of the bracket should be about 1.5 meters from the floor to facilitate
operation.

5
H
Figure 5 Schematic Drawing of Bracket Dimensions
4. OPERATION
1) Remove the cover protecting the base plate surface (The Base Plate should be kept covered
when not in use.)
2) Referring to Figure 6, move the right sliding sight (A1) so that when looking through the
hole in the sight, the pendulum wire lines up with the left front sight (A). Read and record the
reading on the steel rule to the nearest millimeter.
3) Repeat Step 2 for the left sliding sight (B1), aligning it with the pendulum wire and the front
right sight (B). Read and record the steel rule reading to the nearest millimeter.
4) The calculation of the X and Y coordinates is done by software loaded as an app onto an
Android smart phone. The software can be downloaded off the Geokon website. Selecting
the App brings up the screenshot shown in Figure 4. Using the touch screen, enter the values
of A1 and A2 in millimeters and then touch the ‘calculate’ icon whereupon the X and Y
coordinates appear in the center of the screen.

6
Figure 6 - Showing the Collimation Process
Figure 7 - Screen-Shot of the Android Software Output

7
5. DATA REDUCTION FORMULAS FOR MANUAL SIGHTING and
READING TABLE
An alternative way to calculate the X Y coordinates is to use the following equations:
Step 1: Let ‘The scale reading B1(mm)’ = B1 ,‘The scale reading A1(mm)’=A1
Step2: Let θ=0.23539256 (rad)
Step3: Define k1, k2, where:





−
+
=
−
+−=
)
300
101
tan(
2
)
300 1340
tan(
1B
k
A
k
θ
θ
Step 4: Output
Coordinates X (mm):
12
)
21
(56 kk kk
X−
+×
=
Coordinates Y (mm):
12 21
112
56 kk kk Y−
××
+=
Note: Demo calculation XLS for Manual Sighting and Reading Table attached.