DSTT Setup and Adjustment

NME17C0001H001 Page 1



Setup and Adjustment


January 22, 2004


Course Objectives 2

DSTT Parameters 3

Depth 3

Speed/Torque 4

Timeout 5

Pressure 6

Setting the Parameters 6

Controlling Parameters in Chronological Order 9

Stud Removal Parameters 9

Stud Insertion Parameters 13

Manual Parameters 16

Operational Troubleshooting 17

When Latching/Unlatching or Engaging/Disengaging 18

When Engaging 1st Threads 21

When Reaching the Bottom of the Threads 22


With a malfunction in DSTT operation, the Maintenance Mechanic will use technical guides and troubleshoot and set up the DSTT for proper operation as demonstrated by completion of Lab Practical Evaluation.


EO01 Set up the DSTT parameters

EO02 Identify controlling parameters for DSTT operations

EO03 Identify potential operational concerns and adjust parameters to correct them

EO01 Set up the DSTT parameters

First Look at the Parameter Chart to identify the purpose for each of the parameters.


The Depth values shown on the control panel screen are Indicated display numbers. The Indicated display numbers use the “home” position as an approximate zero. The entire Indicated display group can be adjusted together using an “offset” bias described later.

Some of the parameters are Relative numbers. The relative numbers do not show on the screen. They are the difference between what is shown and the reference location. The reference location is set when the tool sets down fully on the stud to engage the stud. Only the individual parameters are adjustable, not the group.

The following are the depth parameters and their purposes. All depth measurements are in millimeters.

Offset Near and Offset Far – Sets the “Bias” signal, adjusting the displayed depth measurement by adjusting the zero location. This is the only depth parameter that is individually adjustable (near and far tool). The offset is used to compensate for variations in depth at a measurement reference location.

Home – The tool home position must be less that this number for the Auto function to start.

Stud Max – This is the absolute maximum depth. It shuts off some functions when the number is passed. You can still go further down only in the manual mode.

Open/Close Latch – Location must be less than this number for auto function – a message to Open/Close latch is displayed.

In Latch – The location must be greater than this number for the auto engage/disengage function.

Latch Missed – After unlatching, the tool must pass this number to tell the tool that you are out of the latch. There is a time limit for this function. A secondary function, in auto, the lowering function will speed up after passing this number.

Above Thread – Unless lower in elevation (larger number) than this relative number, cannot turn the stud in auto.

Fast Start – Changes from slow to fast mode and fast to slow in auto when the tool depth passes this relative number, both up and down.

Found Head – In auto, the tool stops rotation when it drops this far after sensor rod touches the stud

Search Head Low – In auto, backwards to search for triangle (removal) or drop onto 1st thread (install) is not allowed until greater than this number.

Start Slow Diff – Tool speed changes speed when within this distance from the bottom position, both installing and removing, auto (Fast to Final/High torque to fast) and manual (Fast to Slow/Slow to Fast).

Final Position Auto – This is the bottom position in auto – The tool stops threading in when past this relative number.

Manual Slow – Tool speed changes when this distance is passed in manual, both up (fast to slow) and down (slow to fast).

Max Depth – The bottom position in manual – stops threading in when past this number.


The speed is listed 1st and torque second for each parameter on the screen. These numbers are a percentage (%) of full speed/torque. The following lists when the parameter is in effect.

Search CW – Not used

Search CCW – In Auto when the tool is turning to find the stud triangle to drop onto the stud and for finding the 1st thread when inserting the stud.

Remove Fast – In Auto when removing stud in the fast region of travel (between relative positions, Final Position Auto and Fast Start).

Insert Fast – In Auto when inserting stud within the fast region of travel (between relative positions, Fast Start and Final Position Auto plus Start Slow Diff).

Thread Out – In Auto when removing the stud in the upper slow region (above Fast Start).

Thread In – In Auto when inserting stud in the upper slow region (above Fast Start).

High torque – In Auto when first removing stud until movement distance of Start Slow Dif occurs.

Final – In Auto when inserting studs in the bottom slow region (within Start Slow Dif of Final Position Auto).

Manual Slow – Manual operation when inserting or removing studs above position Manual Slow and within Start Slow Diff of Max Depth.

Manual Fast – Manual operation when inserting or removing studs between positions Max Depth plus Start Slow Diff and Manual Slow.


The Timeout functions only exist in automatic other than Tool Stalled. All times are in seconds.

Lift/Lower – Time allowed for lowering tool to the stud or raising tool from the stud.

Search – Time allowed between sensor rod touching and dropping the Found Head distance while tool is turning. The first fault will allow the tool to repeat the attempt.

Lift to Repeat – After lifting, the time allowed to repeat the Search function.

Lower to Engage – The time from completing the Search / Lift to Repeat function or reaching Final Position Auto until the upper proximity probe indicates the tool fully down on the stud.

Check to Disengage – After tool disengaged light comes on, this is the time allowed until the sensor rod comes off the stud.

Lift to Latch – The time for the tool to go above the Latch/Unlatch position after engaging the stud (during installation) or passing the Above Thread depth (during removal).

Lower to Thread – After unlatching and pressing the Start button, the time until the tool must be below the Above Thread position.

Wait on Thread – After stopping on the threads (below Above Thread) the time until the stud drops past the first thread while turning CCW.

Install/Remove – Time from when the tool begins turning until it reaches the Final Position Auto (install) or Above Thread (remove).

Tool Stalled – No rotation of the motor occurs for this time, auto or manual.

Latch Missed – Time for the tool to go below the Latch Missed position after unlatching and pressing Start


The pressure parameters are Individual Parameters. Each tool (near and far) is individually adjusted. Manual pressure regulators in the lower cabinet on the opposite side from the control panel set a maximum pressure for all evolutions and the value for the top of the piston during Down, No Stud operations. At the panel, you are setting the electronically regulated pressure under the piston only. All pressure values are shown in millibars (thousandths of an atmosphere). One bar is about 15 psi.

Up, No Stud – The pressure to raise the tool only – no stud is attached. It functions in manual operation only. There is no use of this parameter in Auto.

Down, No Stud – The pressure to allow the tool only to lower – no stud is attached. The downward force is both gravity and the pressure regulator inside the cabinet. The parameter you set is opposing these downward forces.

Up, With Stud – The pressure to raise tool and stud together.

Down, With Stud – The pressure to allow the tool and stud to lower with gravity forces only (no pressure above the piston).

Turning Compensation – The pressure to support the weight of the tool and stud without allowing them to move.

Setting the Parameters

Now let’s look at setting of the parameters. This is a look at the how only, not the why or which direction to change it. We will try to understand that in the next objective.

Using the chart given, you can easily set up the parameters. This would apply for instance if a memory card had to be replaced or a PLC (computer). Let’s look at how to enter a parameter, either initially or to change one.

Setup to Enter the Parameters

·  Press the general parameter category button to be entered (Depth, Speed/Torque, Timeout/ Pressure (Prop)).

·  Wait for the password screen to come up fully (Blinking asterisks on the bottom of the screen) then enter the password. Press Enter.

·  Press the parameter category button again and you are ready to enter the parameters.

Entering parameters

·  Cursor down or up to the parameter to be changed.

·  Enter the new value and press Enter.

·  If a mistake is made, press Escape to reset the number. If the mistake has already been entered, simply enter a corrected number.

·  When finished entering all parameters in that general category, press Escape.

·  This can be repeated for parameters in any other category.

Adjusting pressure parameters

The necessary pressure for proper operation can vary depending on O-ring resistance and manual regulator setpoints, so they will be the most commonly adjusted parameters. Each should be set under appropriate conditions so it will perform its function properly. The following is a good overview on how this can be done. Unlike the old SHVs, one setpoint is not dependent on any other, so the order of setting them is not critical except to set the manual regulator for Down, No Stud prior to the computer regulator setpoint for that parameter.

Place the DSTT in manual to perform the operations.

Down, No Stud

·  With the tool up, press the Lower Tool button

·  Raise the setpoint until the tool will not go down

·  Lower the setpoint by 50 millibar increments until the tool lowers smoothly

Too low a pressure and the tool will turn the stud when searching for the triangle and “bang” down when found.

Up, No Stud

·  With the tool down, press the Lift Tool button

·  Raise pressure until the tool lifts smoothly – 200-300 millibars extra doesn’t hurt anything

Pressure should not be high enough to lift a stud, otherwise it is not critical.

Up, With Stud

·  With stud engaged and tool down, press Weight Comp On/Off to turn on Weight Compensation

·  Press the Lift Tool button

·  Raise pressure until the tool with the stud lifts smoothly – 100-200 millibars extra doesn’t hurt anything

Too high a pressure can damage the first thread when removing..

Down, With Stud

·  With stud engaged and tool up, press Weight Comp On/Off to turn on Weight Compensation

·  Press the Lower Tool button

·  Lower pressure until the tool with the stud goes down smoothly – 100-200 millibars extra doesn’t hurt anything

Too low a pressure can cause the stud to drop hard past the 1st thread.

Too high a pressure can prevent the stud from dropping into the 1st thread.

NOTE: This parameter is also used to remove the tool from off the stud when disengaging in auto – if pressure is too low the tool will not come off the stud

Turning Compensation

·  With stud engaged, press Weight Comp On/Off to turn on Weight Compensation

·  Lift or lower the stud to suspend it and press the Weight Comp On/Off button to stop the movement

·  Press the Weight Comp On/Off button again with no Lift or Lower function

·  If tool and stud move, raise or lower the setpoint to stop the movement

Ideally, raise the pressure setpoint just enough to initiate upward movement, then lower it just enough to initiate downward movement. The setpoint can then be set between those two values.

EO02 Identify controlling parameters for DSTT operations

Now let’s put together the information from the first objective in another way. Let’s look at the chronological order of events and identify each controlling parameter during each individual event. This way, if something does not function, we can have a good idea of which parameters or sensors need to be checked. This information is also contained in Table form to condense it into a single sheet for stud removal and a single sheet for stud installation.

The information is broken down into small segments that have a defined starting and ending point. The header describes the segment. The starting point is either defined in the header or is the Destination of the preceding segment.

For Stud Removal

Note: when pushing start, if the auto function is not ready to operate (wrong selector switch position or Start button is blinking, e.g.) the operation may appear to start, but will try to perform the wrong evolution at some point. The problem, though, is not in the parameter settings. Switch to Manual to recover.

Push Start – Tool lowers to stud

·  Pressure – Down, No Stud

·  Time limit – Lift/Lower

·  Destination – Sensor rod activates lower proximity ring when below the Search Head Low position

·  Also releases the X-Y slide

Tool rotates to align triangles

·  Pressure – Down, No Stud

·  Time limits – Search and Lift to Repeat

·  Torque/Speed – Search CCW

·  Destination – Drops by Found Head amount

Tool stops turning and finishes dropping

·  Pressure – Down, No Stud

·  Depth is not a factor

·  Time limit – Lower to Engage

·  Destination – Sensor rod upper proximity probe activated indicating tool is fully down on the stud

·  Relative zero position is determined at this point. The relative zero position is actually the position when setting in the latch, so that position is assumed here to be at Final Position Auto higher than the current tool position. All the relative positions will actuate base on this position.