Skip to contentUnited States Department of Transportation - Federal Highway Administration FHWA Home
Research Home   |   Pavements Home
REPORT
This report is an archived publication and may contain dated technical, contact, and link information
Publication Number: FHWA-HRT-07-040
Date: October 2011

 

Falling Weight Deflectometer Calibration Center and Operational Improvements: Redevelopment of The Calibration Protocol and Equipment

APPENDIX F. HARDWARE USE AND INSTALLATION GUIDE

OVERVIEW/SCOPE

The purpose of this guide is to describe the installation and proper use of the following components of the FWD calibration system (see figure 103):

The instructions provided here assume the use of the WinFWDCal software package.

Figure 103. Photo. Calibration system components. This photo shows the various components of a falling weight deflectometer (FWD) calibration system including the geophone calibration stand, seismometer calibration stand, reference load cell, Vishay signal conditioner, ball-joint anchor, accelerometer box and calibration platter, Keithley KUSB data acquisition board with pushbutton, load cell and signal conditioner shipping case, FWD laptop with storage bag, geophone adapters, concrete anchors, universal serial bus key, handles for calibration stands, hex wrenches, and associated cables. Each part is labeled accordingly.

Figure 103. Photo. Calibration system components.

FACILITIES

Calibration center facilities require the following characteristics:

TEST PAD

While a specially built test area for FWD calibration is not required by AASHTO R32-09, some agencies either need or prefer to build a concrete test pad.(1) If so, the test pad should have the following specifications:

REFERENCE LOAD CELL

Parts and Tools

Table 41. Parts and tools for load cell calibration.
Tool/Equipment Quantity Notes
Reference load cell assembly 1 Drawing CLRP-LC01
¼ 28 x 1-inch socket head cap screw 6 McMaster-Carr® part number (p/n) 92196A325
¼ 28 x ¾-inch socket head cap screw 6 McMaster-Carr® p/n 92196A321
Vishay signal conditioner 1  
Load cell signal cable 1 Drawing CLRP-DAQ02
316-inch hex wrench 1  
Torque wrench 1 Capable of 100 inch-lbf

1 inch = 25.4 mm
1 lbf = 4.45 N

Figure 104. Photo. Reference load cell assembly.

Figure 104. Photo. Reference load cell assembly.

Calibration

The reference load cell requires annual calibration to ensure accuracy. To calibrate the reference load cell, a universal testing machine with a load capacity of 120,000 lbf (500 kN) or more is needed. Although the load cell is calibrated to only 24,000 lbf (107 kN), the higher capacity of the testing machine assures that the test frame will be adequately rigid.

The Vishay 2310 signal conditioner, Keithley KUSB-3108 DAQ, the reference load cell, and the load cell signal cable are considered one system and must be calibrated together. Once the calibration is complete, it only applies to the entire system that was used during the calibration. If any component of the system changes, then the load cell needs a new calibration.

The bolts that hold the cover plate and feet onto the load cell (see figure 105) should not be removed under any circumstances. If any of these bolts are removed, the load cell calibration becomes invalid and must be returned to an approved calibration center for recalibration.

Figure 105. Photo. Bottom view of the reference load cell.

Figure 105. Photo. Bottom view of the reference load cell.

Use

  1. Ensure that the guide fingers are tightened to the load cell body during FWD load cell calibration.

  2. Attach the signal cable form the load cell to the signal conditioner and allow the electronics to warm up for at least 1 h.

  3. Carefully align the reference load cell under the FWD load plate, ensuring that the guide fingers and the load plate do not interact (see figure 106).

  4. Follow the on-screen instructions provided by WinFWDCal for a complete load cell calibration.

Figure 106. Photo. Reference load cell positioned under the FWD load plate. This photo is a view of the underside of the Dynatest ® falling weight deflectometer (FWD) with the reference load cell aligned under the FWD load plate. The reference load cell is seen underneath the load plate, and the wheels from the FWD trailer can be seen.

Figure 106. Photo. Reference load cell positioned under the FWD load plate.

CONCRETE ANCHOR INSTALLATION

The concrete anchors suggested for use with the FWD calibration hardware are of the drop-in variety (see figure 107). These instructions are for anchors from McMaster-Carr® p/n 97082A031 only. For any other equivalent anchor, refer to the manufacturer’s installation instructions.

Parts and Tools

Table 42. Parts and equipment for concrete anchor install.
Tool/Equipment Quantity Notes
Concrete anchors 2 McMaster-Carr®, p/n 97082A031
Anchor setting tool 1 McMaster-Carr® p/n 97077A120
Hammer 1  
Drill 1 Optionally a hammer drill
¼-inch masonry drill bit 1  
½-inch masonry drill bit 1  
38-inch inside diameter washers 2 McMaster-Carr® p/n 94744A273

1 inch = 25.4 mm

Figure 107. Photo. Concrete anchor. This photo shows three elements from left to right: a hex head cap screw, a washer, and a concrete anchor.

Figure 107. Photo. Concrete anchor.

Installation

  1. Determine the appropriate location for the ball-joint anchor on the test pad. The FWD needs to impart a deflection of 16–24 mil (400–600 μm) at a 16,000-lbf (71-kN) load where the ball-joint will be located.

  2. Using the base bar from the ball-joint anchor (B04, drawing CLRP-BJ03) as a guide, mark where the two anchors will be installed. The holes should be 6 inches (152.4 mm) apart from center to center.

  3. Drill pilot holes at the anchor locations using a ¼-inch (6.35-mm) masonry bit and, if available, a hammer drill. The holes should be slightly greater than 1.5 inches (38.1 mm) deep to ensure that the anchor rests below the surface of the concrete. Ideally, the holes will be drilled about 116 inches (1.59 mm) deeper than the height of the anchor (see figure 108).

Figure 108. Photo. Concrete anchor installation step 3. This photo illustrates the third step

Figure 108. Photo. Concrete anchor installation step 3.

  1. Drill the final holes for the anchors with a ½-inch (12.7-mm) bit. Do not use a hammer drill for these holes.

  2. Blow out the debris from holes with compressed air.

  3. Drop the anchors into the holes and gently tap on the top of the anchor with a hammer to insert it into the hole. Be careful not to damage the anchor. If the anchor does not sit flush in the hole, do not attempt to drive it in by striking the anchor itself directly because this will damage the anchor. If necessary, remove the anchor and drill a little deeper (see figure 109).

Figure 109. Photo. Concrete anchor installation step 6. This photo illustrates the sixth step in concrete anchor installation, where the anchors are tapped into position. A person is lightly hammering in the anchor into the hole that was created in step 3.

Figure 109. Photo. Concrete anchor installation step 6.

  1. Once the anchors are at the correct depth in the hole, use the setting tool to expand the anchor by placing the setting tool inside the anchor and striking it with a hammer (see figure 110).

Figure 110. Photo. Concrete anchor installation step 7.

Figure 110. Photo. Concrete anchor installation step 7.

BALL-JOINT ANCHOR

Parts and Tools

Table 43. Tools and equipment for ball-joint assembly.
No. Part/Equipment Quantity Notes
B01 Ball-joint 1 Techno/Sommer KG-60
B01a Ball 1 Techno/Sommer KG-60
B01b Socket 1 Techno/Sommer KG-60
B01c Clamp 1 Techno/Sommer KG-60
B01d Screw 2 Techno/Sommer KG-60
B02 Clamp 1 Drawing CLRP-BJ01
B03 Clamp base 1 Drawing CLRP-BJ02
B04 Base bar 1 Drawing CLRP-BJ03
B05 Rest stop 1 Drawing CLRP-BJ04
B06 M6 x 16-mm socket head cap screw 4 McMaster-Carr®
p/n 91292A135
B07 M8 x 16 mm socket head cap screw 6 McMaster-Carr®
p/n 91292A145
B08 M8 x 25 mm socket head cap screw 2 McMaster-Carr®
p/n 91292A148
B09 Loctite® #242 threadlocker 1  
B10 5-mm hex wrench 1  
B11 6-mm hex wrench 1  
B12 Dow Corning Molykote G-4500 alum thickened grease, 14.1-oz, Nlgi #2   McMaster-Carr®
p/n 4328T24

1 inch = 25.4 mm
1 oz = 28.35 g

Figure 111. Photo. Parts and tools for ball-joint assembly. This figure shows the parts and tools necessary for ball-joint assembly. The parts are spread out on a flat surface, and the picture is taken above them. The parts and tools include a ball-joint, ball, socket, clamps, screws, a clamp base, a base bar, a rest stop, and two wrenches.

Figure 111. Photo. Parts and tools for ball-joint assembly

Assembly

  1. Attach the clamp (B02) to the clamp base (B03) with two M8 x 0.975-inch (25-mm) socket head cap screws (B08). Note: Do not apply Loctite® to the two screws.

    Note: Do not apply Loctite® to the two screws.

  2. Completely disassemble the ball-joint (B01) by removing its two screws (B01d). Thoroughly clean all old lubricant off the ball and socket and apply a thin layer of Molykote® type G lubricant (B12) on the mating surfaces.

  3. Use Loctite® and three M8 x 0.624-inch (16-mm) socket head cap screws (B07) and mate the ball-joint’s ball (B01a) and the clamp components assembled in step 1 through the counterbored holes in the ball.

  4. Reassemble the ball-joint (B01).

    Note: Do not apply Loctite® when installing the screws (B01d).

  5. Attach the base bar (B04) to the completed ball-joint assembly with Loctite® (B09) and three M8 x 0.624-inch (16-mm) socket head cap screws (B07) through the counterbored holes in the bottom of the base bar. The ball-joint screws (B01d) must be aligned along the length of the base bar for access as shown in figure 112.

  6. Slide the rest stop (B05) over the ball-joint assembly and secure it to the base bar (B04) with four M6 x 0.624-inch (16-mm) socket head cap screws (B06). See figure 113 for a photograph of the assembly of the ball joint anchor.

Figure 112. Photo. Proper alignment of ball-joint screws. The photo shows a cutaway view of the assembled ball-joint anchor showing the ball-joint screws facing left towards the opening in the side of the rest stop. An arrow pointing to the left indicates the direction of the screws.

Figure 112. Photo. Proper alignment of ball-joint screws.

Figure 113. Photo. Assembly of the ball-joint anchor. The photo shows a series of images depicting steps 1–6 of the ball-joint anchor assembly from top to bottom as well as larger images of the completed ball-joint after step 4 and the fully assembled ball-joint anchor. The steps are as follows: (1) assemble the clamp, (2) disassemble the ball joint, (3) attach the ball joint to the clamp, (4) reassemble the ball joint, (5) attach the ball joint to the base plate, and (6) attach the rest stop.

Figure 113. Photo. Assembly of the ball-joint anchor.

ACCELEROMETER BOX

Parts and Tools

Table 44. Parts and tools for accelerometer box assembly.
No. Part/Equipment Quantity Notes
A01a Accelerometer assembly 1  
A01a Accelerometer 1 Silicon Designs model 2220-005
A01b Amphenol PT02A-10-6P box mounting receptacle 1 Mouser p/n 654-PT02A106P
A01c Accelerometer wiring 1 Drawing CLRP-AB05
A02 Box bottom 1 Drawing CLRP-AB02
A03 Box top 1 Drawing CLRP-AB03
A04 Calibration platter 1 Drawing CLRP-AB04
A05 #4-40 x 38-inch flat head Phillips machine screw 4 McMaster-Carr® p/n 96877A209
A06 #4-40 x ½-inch pan head Phillips machine screw 2 McMaster-Carr® p/n 91400A110
A07 #4 retaining washer 2 McMaster-Carr® p/n 91755A205
A08 #4-40 x ¼-inch fillister head Phillips machine screw 7 McMaster-Carr® p/n 91737A072
A09 #10-24 x ½-inch knurled head thumbscrew 2 McMaster-Carr® p/n 91746A876
A10 Bubble level, glass surface mount 1 McMaster-Carr® p/n 2198A85
A11 Leveling mount with polyethylene base, 38-inch
16 x 1-inch stud
3 McMaster-Carr® p/n 23015T64
A12 38-inch 16 locking wig nut 3 McMaster-Carr® p/n 98520A145
A13 #1 Phillips head screwdriver 1  
A14 Loctite® #242 threadlocker 1  

1 inch = 25.4 mm
Note: Blank cells indicate that no notes are available.

Assembly

  1. The accelerometer is attached to the box top (A03) using two #4-40 x ½-inch (12.7-mm) pan head machine screws (A06) with #4 nylon retaining washers (A07). The sensor element of the accelerometer must be oriented in the correct alignment. The element is marked on the casing of the accelerometer as shown in figure 114. This element must be centered on and mated to the inside face of the box top.

  2. Coil the accelerometer wiring (A01c) into the box top and slide the wire through the channel in the front of the box top so that Amphenol receptacle (A01b) sits flush against the front of the box.

  3. The Amphenol receptacle (A01b) is attached to the face of the box top with four #4-40 x ½-inch (6.35-mm) fillister head machine screws (A08) and medium strength Loctite® #242 (A14).

  4. The box top and box bottom (A02) are mated together with four #4-40 x 38-inch (9.52-mm) flat head machine screws (A05) and medium strength Loctite® #242 (A14). The final assembly is shown in figure 115.

Figure 114. Photo. Parts for accelerometer box assembly. The photo shows an enlarged view of the accelerometer box, and the individual parts are numbered. The upper left shows the rectangular shell of the accelerometer box assembly. The upper right shows the calibration platter with bubble level in the upper left corner and wing nuts attached to leveling feet in three locations. Two knurled nuts are aligned with screw holes on the platter. The lower right shows the electrical connector and accelerometer with connecting wiring. The lower left shows the bottom plate with four machine screws.

Figure 114. Photo. Parts for accelerometer box assembly.

Figure 115. Photo. Accelerometer box assembly. The photo shows a series of images depicting, from top to bottom, the four steps to assemble the accelerometer box, as well as a larger image of the completed assembly. The steps are as follows: (1) attach the accelerometer to the top box, (2) adjust the wires and slide the electrical connector into position, (3) attach the electrical connector to the top box, and (4) attach the bottom of accelerometer box.

Figure 115. Photo. Accelerometer box assembly.

Calibration Platter Assembly

  1. Attach the bubble level (A10) to the calibration platter (A04) with three #4-40 x ¼-inch (6.35-mm) fillister head machine screws (A08). Note that the threaded holes for the thumbscrews are not centered on the side of the calibration platter. Check for proper alignment of the accelerometer box on the platter before mounting the bubble level..

  2. The three leveling mounts are threaded into the calibration platter and topped with three 38-inch (9.52-mm) 16 locking wing nuts (A12).

  3. The accelerometer box is attached to the calibration platter with two #10-24 x½-inch (12.7-mm) knurled head thumbscrews (A09) as shown on the left in figure 116.

Figure 116. Photo. Accelerometer box attached to calibration platter. This photo shows two views of the attachment of the accelerometer box to its calibration platter. This left panel is taken from above showing how the platter, accelerometer box, and screws line up with each other. The right panel shows a top view of an aluminum accelerometer box attached to an aluminum calibration platter. The accelerometer box is attached to the front of the platter by two knurled thumb screws. Three wing nuts attached to feet are used to level the platter. A bubble level on the back left corner of the platter is used to confirm that the platter is level.

Figure 116. Photo. Accelerometer box attached to calibration platter.

Accelerometer Storage

  1. When not in use, attach the accelerometer box to the calibration platter with the two #10-24 knurled head thumbscrews (A09) provided.

  2. The accelerometer needs to be stored on the platter and be level for a minimum of 24 h prior to use.

Accelerometer Calibration

  1. Place the calibration platter, with the accelerometer box attached, on a flat surface and carefully level the platter.

  2. Remove the thumbscrews and press the accelerometer box on to the calibration platter with a finger. Otherwise, the weight of the cable may pull the accelerometer box onto the floor.

  3. While following the on screen instructions from WinFWDCal, continue to press the accelerometer box to the calibration platter.

  4. Flip the accelerometer box over when instructed.

CALIBRATION STANDS

Parts and Tools

Table 45. Equipment for calibration stand assembly.
Number Tool/Equipment Quantity Notes
S01 Geophone calibration stand assembly 1 Drawing CLRP-GCS01
S02 Seismometer calibration stand
assembly
1 Drawing CLRP-SCS01
S03 Phenolic handle, 38-inch
16 x ½-inch stud
4 McMaster-Carr® p/n
62385K65
S04 Bubble level, glass surface mount 2 McMaster-Carr® p/n 2198A85;
Also No. A10 in this guide.
S05 #4-40 x ¼-inch fillister head Phillips machine screw 6 McMaster-Carr® p/n
91737A072; Also No. A08 in this guide.
S06 Carl Bro geophone adapters with
M8 1 mm threaded through hole
10 Morton Machine Works p/n
KK-GA02
S07 JILS geophone adapter with 38-inch
24 threaded through hole
0 Morton Machine Works p/n
KK-GA03
S08 ¾-inch inside diameter washer 10 McMaster-Carr® p/n
90126A036
S09 38-inch inside diameter washer 10 McMaster-Carr® p/n
94744A273
Also No. B11 in this guide.
S10 38-inch -24 x 58-inch hex head cap
screw
10 McMaster-Carr® p/n
92865A212
S11 #10-24 x ½-inch knurled head thumbscrew 2 McMaster-Carr® p/n
91746A876; Also No. A09 in this manual
S12 Two-piece clamp-on shaft collar
20-mm bore, 40-mm outside diameter
10 McMaster-Carr® p/n 6063K19
S13 Magnet assembly with #10-24 button head cap screw and nut 10 McMaster-Carr® p/n 5685K26,
p/n 92949A246, and p/n
90730A011
S14 Modified knurled rim knob 10 McMaster-Carr® p/n 6121K93

1 inch = 25.4 mm

Assembly

See figure 117 for a photograph of the equipment necessary for calibration stand assembly.

  1. The bubble level (S04) is fastened to the handle holder of either stand (S01 or S02) with three #4-40 x ¼-inch (6.35-mm) fillister head machine screws (S05). Since there are four potential places to attach the level, the calibration center operator should determine which location is appropriate for visibility and comfort during use.

  2. Two phenolic handles (S03) are screwed in place at one of the two available positions depending on the preference of the operator.

  3. The pushbutton assembly (described elsewhere) should be attached with Velcro® to the stand at the same level as the handles and in a spot where it can be easily reached during use. See figure 118 for an example.

  4. For both the geophone calibration stand and the seismometer calibration stand, the connector pin is fastened to the stand with medium strength Loctite® #242. Figure 125 shows the geophone calibration stand with a connector pin attached.

Figure 117. Photo. Equipment for calibration stand assembly. This photo depicts all of the parts necessary for calibration stand assembly except for the KUAB geophone adapter. This includes the geophone stand, seismometer stand, phenol handle, bubble level, Carl Bro adapter, two JILS adapters, bubble level attachment machine screws, two each of the large and small washers, and an attachment bolt.

Figure 117. Photo. Equipment for calibration stand assembly.

Figure 118. Photo. Calibration stand with handles, bubble level, and pushbutton. This photo shows a view of the placement of the calibration stand handles, bubble level, and pushbutton. The stand is vertical on a flat surface with two handles coming out of each side of it. The pushbutton is attached to the calibration stand using Velcro ® below the handles. A yellow arrow points to the pushbutton on the right side of the stand.

Figure 118. Photo. Calibration stand with handles, bubble level, and pushbutton.

Location of Accelerometer Box

On the geophone calibration stand, the accelerometer box is fastened to a shelf half way up the stand with two #10-24 x ½-inch (12.7-mm) knurled head thumbscrews (S11).

On the seismometer calibration stand, the accelerometer box sits in the middle of the third shelf up on the stand and is held on with two thumbscrews (S11). The accelerometer box needs to be attached before the seismometers to ensure ease of use.

Deflection Sensors

For the geophone calibration stand, there are four different types of geophones that can be calibrated: Carl Bro, Dynatest®, KUAB, and JILS.

The Carl Bro and the JILS geophones are fastened to the stand in similar manners, though they each require their own adapters. The geophone and its respective adapter (S06 and S07) screw together with a ¾-inch (19.05-mm) inside diameter washer (S08) placed between the adapter and shelf of the stand and a 38-inch (9.53-mm) inside diameter washer (S09) placed between the geophone and the shelf. Figure 119 shows a JILS geophone and adapter fastened to the stand. Carl Bro geophone adapters (S06) have different size threads and are painted red.

The Dynatest® geophones use a magnet to couple to the stand (see figure 120). To accomplish this, the JILS adapter (S07) is turned upside down and fastened to the stand with a 38-inch (9.53-mm) to 24 x 58-inch (609.6 x 15.88-mm) hex head cap screw (S10) as shown in Figure 121. The Dynatest® geophone then sits on top of the adapter.

The KUAB geophones use a collar (S12), magnet (S13), and modified knob (S14) to attach to the stand, as shown in figure 122 and figure 123. The knobs are painted gold. The modifications to the knob are to drill and tap for a #10-24 machine screw thru the length of the knob, and to mill out a 18-inch (3.18 mm) deep by 1-inch (25.4-mm) diameter recess at the top of the shank to allow the magnet assembly to fit inside.

Figure 119. Photo. Placement of the accelerometer box on the geophone stand. This photo shows the vertical geophone stand on a flat surface with two handles coming out of each side. The accelerometer box is shown in position on the accelerometer shelf below the handles. The two attachment screws are shown to the side.

Figure 119. Photo. Attachment of a JILS or Carl Bro geophone to the stand.

Figure 120. Photo. KUAB geophone adapter equipment. This photo shows KUAB geophone adapter equipment. On the left is the clamp that hooks to the KUAB geophone. On the right is a magnetic cup with a bolt that screws into a black knurled knob that is painted gold around the knurled end.

Figure 120. Photo. Placement of the accelerometer box on the geophone stand.

Figure 121. Photo. Attachment of a JILS or Carl Bro geophone to the stand. This photo shows the attachment of JILS geophones in the calibration stand and a close-up of an attached JILS sensor. The left panel shows the six components in an unassembled layout. The components are the JILS geophone, which is an orange plastic cylinder with a wire out the back and a bolt out the bottom, a small upper washer, a large lower washer, a black knurled knob, and the front side of the geophone stand with a notched shelf for placing the geophone. The right panel shows the JILS geophone bolted to the knob in the stand.

Figure 121. Photo. Attachment of a Dynatest® geophone to the stand.

Figure 122. Photo. Attachment of a Dynatest ® geophone to the stand. This photo shows the attachment of Dynatest ® geophones in the calibration stand and a close-up of an attached Dynatest ® sensor. The left panel shows the six components in an unassembled layout. The components are the Dynatest ® geophone, which is a yellow plastic cylinder with a wire out the front, a black knurled knob, a large upper washer, a small lower washer, an attaching bolt, and the front side of the geophone stand with a notched shelf for placing the geophone. The right panel shows the Dynatest ® geophone magnetically attached to a knurled knob and the knob bolted into place in the stand.

Figure 122. Photo. KUAB geophone adapter equipment.

Figure 123. Photo. Attachment of a KUAB geophone adapter. This photo shows the KUAB geophone adapter attached in the stand in the hollow groove. The left panel shows the six components in an unassembled adapter. The components are the clamp that holds the KUAB geophone, a magnetic cup with a bolt sticking out the bottom, a large lower washer, a black knurled knob that is painted gold around the knurled end, and the front side of the geophone stand with a notched shelf for placing the geophone. The right panel shows the clamp is

Figure 123. Photo. Attachment of a KUAB geophone adapter.

For the KUAB seismometer calibration stand, the seismometers are aligned in a two-column configuration as shown in figure 124. Users should tighten the setscrew at the bottom of the seismometer onto the standoffs on the stand.

Figure 124. Photo. Seismometer stand with sensors attached. This photo shows seven seismometers attached to the bottom positions in a two-column seismometer stand. The 
stands are in a room positioned vertically on the ground, and the frame of the falling weight deflectometer is seen in the background.

Figure 124. Photo. Seismometer stand with sensors attached.

Using the Stand

During deflection sensor calibration, the calibration stand should be set up in the following order:

  1. Attach the stand to the ball-joint anchor.

  2. Fasten the accelerometer box to the stand after the accelerometer has been calibrated.

  3. Place the deflection sensors in the correct configuration as shown on screen in the WinFWDCal program.

  4. Use Velcro® to attach the pushbutton to the stand.

The following procedure is used when going from one trial to the next in relative and reference calibration:

To couple the stand to the ball-joint, use the following:

Figure 125. Photo. Coupling the calibration stand and ball-joint anchor. This photo shows

Figure 125. Photo. Coupling the calibration stand and ball-joint anchor.

DATA ACQUISITION SYSTEM

Parts and Tools

Table 46. Parts and equipment for data acquisition.
No. Tool/Equipment Quantity Notes
USB Standard USB cable 1  
D01 Vishay to KUSB DAQ cable 1 Drawing CLRP-DAQ01
D01A Vishay 2310B to KUSB DAQ
cable
1 Drawing CLRP-DAQ01A
D01B Vishay 2310B to DAQ cable
(stock parts)
1 Drawing CLRP-DAQ01B
D02 Vishay to load cell cable 1 Drawing CLRP-DAQ02
D03 Accelerometer signal cable 1 Drawing CLRP-DAQ03
D04 Pushbutton to KUSB DAQ
cable
1 Drawing CLRP-DAQ04
D05 Keithley KUSB-3108 16-bit
DAQ
1  
D06 Vishay 2310 signal
conditioner
1  

Note: Blank cells indicate no notes area available.

Cable Assembly

All cables should be fabricated according to their respective drawings. A full set of calibration cables includes an accelerometer signal cable (D05), a load cell signal cable (D04), a Vishay to KUSB DAQ cable (D03), and a pushbutton assembly (D06).

Connection Breakdown

Figure 126 illustrates FWD data acquisition system components and connections. The following list explains the connection breakdown:

Figure 126. Illustration. FWD data acquisition system components and connections. This illustration shows the connections between the various instruments involved in falling weight deflectometer calibration, with labels showing the cables and components. The computer shown on the left is attached via a universal serial bus cable to the KUSB data acquisition board. One connection from KUSB goes to the push button assembly. A second connection from KUSB goes to the signal conditioner. From the signal conditioner is a connection to the accelerometer or reference load cell.

Figure 126. Illustration. FWD data acquisition system components and connections.

Vishay 2310 Signal Conditioner Settings

Table 47. Settings for the Vishay 2310 signal conditioner.
Vishay 2310 Setting Load Cell Accelerometer
Excitation 10 V 10 V
Filter 1 kHz 1 kHz
Gain Load cell dependant1 2.0 x 1
Auto balance Procedure dependant2 Always off
AC in Fully extended Fully extended

1Indicates that each calibration center is provided with the correct gain for its reference load cell from the annual calibration.

2Indicates that during the FWD load cell calibration, WinFWDCal provides instruction for when to use the auto balance switch on the Vishay signal conditioner.

COMPUTER

Table 48 presents the minimum requirements for a calibration computer. A laptop is recommended for portability.

Table 48. Minimum requirements for computer hardware.
Item Requirement
Operating system Microsoft Windows XP® SP3 or
later (not including Windows 7®)
Physical memory (RAM) 1 GB
Hard disk space At least 25 GB free space
Video adapter DVI/VGA
Display 17-inch external color monitor
(15-inch liquid crystal display on laptop)
Optical drive CD-RW (DVD ±RW preferred)
Removable storage 3.5-inch floppy disk drive and
256 MB USB flash drive
USB 2.0 ports At least four
Printer Inkjet or laser

1 inch = 25.4 mm
Note: The USB flash drive, 3.5-inch floppy drive, and CD writer are used for transferring data between the FWD computer and the calibration computer.

 


The Federal Highway Administration (FHWA) is a part of the U.S. Department of Transportation and is headquartered in Washington, D.C., with field offices across the United States. is a major agency of the U.S. Department of Transportation (DOT).
The Federal Highway Administration (FHWA) is a part of the U.S. Department of Transportation and is headquartered in Washington, D.C., with field offices across the United States. is a major agency of the U.S. Department of Transportation (DOT). Provide leadership and technology for the delivery of long life pavements that meet our customers needs and are safe, cost effective, and can be effectively maintained. Federal Highway Administration's (FHWA) R&T Web site portal, which provides access to or information about the Agency’s R&T program, projects, partnerships, publications, and results.
FHWA
United States Department of Transportation - Federal Highway Administration