Download MLS Caliper Log Instructions

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Todd’s Operating Instructions for the
Caliper Log
(After USGS operating instructions and typed set of instructions from Rex)
For copies check website
Last Modified October, 2002
Required Equipment
Mineral Logging Systems Inc. Box (Figure 1)
12 V DC
Figure 1. Mineral Logging Systems Inc. (MLS) data logging box (Shown with cover removed)
Caliper Tool (long slender rod with 3 equally spaced legs)
Generator (110AC and 12VDC required, and don’t forget plenty of gas)
Calibration plate (or any circular rings or tubes of known diameter)
Blue datalogging toolbox (misc. tools, cal. plate, adapters, & supplies)
Grease (to seal caliper electronics)
9/16 wrench to remove well caps (if necessary)
Equipment Connections
a. Make sure all power switches are off (there are three switches, all are located on
the plotter adjustment panel: there is a main power switch, switch for the left
plotter pen power, and a switch for the right plotter pen power)
b. Connect AC power to generator (supplies power to chart and caliper)
c. Connect DC power to generator (supplies power to geared motor)
d. Remove cap on caliper and remove the cap on the end of cable
e. Grease screw threads before assembling cable to caliper, then assemble caliper to
cable (may need to change to adapter in tool box if screw threads are the wrong
f. Check caliper legs are securely fastened to caliper
DC Supply
(keep set at
115 AC)
Cable End
AC Plug
(Keep set at
left position)
Figure 2. Rear of MLS datalogger. Keep voltage selection switch set to 115 V AC, generator
switch on the bottom right of photo should be kept switched to the left (OFF)
g. Initial settings for front control panel should be (Figure 3):
i. Set time constant knob to 1
ii. Set rec out knob to 250
iii. Set pr/gr switch to gr
iv. Set cal100/log switch to log
v. Set high/low switch to high
vi. Adjust discriminator knob to 5
vii. Set positive/negative switch to negative
viii. Set normal/reverse switch to normal
Rec. Out Knob
PR/GR Selector Knob
Tool Power Selector Knob
High/ Low
Positive/ Negative
Reverse/ Normal
Left Plotter
Right Plotter
Power Switch
Power Switch
Figure 3. Front of datalogger (for caliper logging, we’ll only be using the right plotter)
Figure 4. Caliper tool and calibration plate. (a) Caliper tool shown with legs partially
open. (b) Calibration plate, markings indicate calibration diameter.
Caliper Leg Control (to open legs)
Make sure the chart power is turned off
Turn current adjust knob CCW to zero
Switch main power on
Switch line current/voltage switch (located under the line voltage/current meter)
to voltage (switch is set to voltage for leg open/close, and set to current for
e. Turn tool power to positive (+ tool power opens, - tool power closes legs)
f. Rotate current adjust knob CW until line voltage meter displays 125 Volts (upper
scale on meter)
g. When meter deflects sharply to 50 V, the legs are completely open, then quickly
switch the tool power switch to off
Powering Up the Caliper Electronics
a. Make Sure the tool power is set to off and the plotter is turned off
b. Set the line voltage/current switch to current
c. Set the tool power switch to positive (all measurements are made with a positive
d. Set current adjust knob until line current (lower scale on meter) displays 50mA
Calibration of Caliper
a. Set the tool power to positive
b. Turn on the right plotter power (we turned off the left plotter and removed the pen
because they kept interfering with each other, but the pen could easily be installed
or removed)
c. Place a caliper leg through the hole in the calibration plate representing the
smallest hole diameter expected to encounter. The numbers underneath each hole
in the calibration plate indicate the diameter for calibration (when you remove the
calibration plate, hold the caliper legs to prevent them from opening completely
and sending the plotter shooting out of control, and possibly messing up your
d. Turn the zero control knob (immediately to the left of the right plotter power
switch) to set the pen to the vertical line on the chart you wish to represent that
diameter (on the left side of chart)
e. Place a leg through the hole in the calibration plate representing the largest
diameter expected to be encountered
f. Use the span control knob (immediately to the right of the right plotter power
switch) to set the pen to the vertical line on the chart you wish to represent that
diameter (on the right side of chart)
g. Repeat the zero and span procedure until no further adjustment is required (This
may require dozens of iterations)
h. Caliper is now calibrated
Note: The caliper seems to be accurate within ½ tick mark on the strip chart. It is more
accurate when the legs are opening to a bigger hole, than when they are closing to a
smaller hole.
Caliper Leg Control (to close legs)
Turn chart power off
Switch tool power to off
Set line current/voltage to voltage
Switch tool power to negative
Set current adjust knob until meter displays 125 volts, continue until meter needle
deflects to 300 volts
f. Legs should be closed
g. Switch tool power off
h. Set current adjust to zero
Logging with the Caliper
a. Close caliper legs
b. Set depth odometer to desired depth. Pull out the knob on the right side of the
strip chart box and twist until the odometer reads the desired value.
c. On the side of the strip chart box, set the chart to scroll Up (it can be set to
Neutral, or to chart when moving down)
d. Start with a chart speed of 10. The controls are also on the side of the strip chart
e. Lower caliper to the desired depth using the controls located on the right side of
datalogger box (there are two levers, one for the gearing and another for forward
and reverse). We used first gear, which has a speed of about 40-ft./ min. Also,
there is a brake on the front of the box, but it may need supervision to hold the
load in place (Rex says it has a tendency to slip if not held down by a person).
f. We had the depth scale underneath the line speed readout set to x10
g. Open caliper legs, then set datalogger for measurement
h. If the ammeter reads less than 50 mA when current adjust is set to 0, you are good
to go, if it reads over 50 mA in the current position, the legs may not be
completely open. Close legs and try again.
i. With legs open at depth, let the system rest for a few minutes to settle; otherwise,
the electronics will drift in the initial measurements.
j. Note: the time drive switch does not appear to work.
k. Commence logging
l. The best calibration occurs after logging. While the legs are still open, check the
calibration, and record this on the chart, since the calibration tends to get messed
up a bit when the legs are opened and closed before testing.
m. After logging, turn off the plotter, close caliper arms, and turn all power switches
to off