Precision Measurement Engineering, Inc.
Precision Measurement Engineering, Inc.
Upward direction profiling is used when measurement
of the surface layer is desired. The host computer and SCAMP control dialog must be
properly installed as described in the Installing
the SCAMP Software, Checking the Batteries , and the Assembling the SCAMP stand sections.
Assembly of SCAMP
SCAMP is most conveniently shipped and stored dis-assembled. It must be assembled prior to
profiling. Assembly is accomplished by the following steps:
| Locate enough expendable weights (rocks) for the profiles you intend to make. Make wire loops from the wire provided by threading the wire through the collar provided to make a loop, then adjusting the loop size using the tool provided. Crimp the collar in place with pliers. Connect the other ends of the wires to the expendable weights so that the weights will hang below the SCAMP by at least 12 inches (30cm). |
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| Place the 5151 float
retainer ring over the sensor cover and onto the SCAMP. Place the retrieval line loop over the sensor cover and onto the SCAMP. Place the float assembly over the sensor cover and onto the SCAMP. |
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| Carefully remove the sensor cover. Do this in a sitting position with the SCAMP rotated so that the Accurate CT sensor is either on the right or left side. Do this so that the relative slant of the sensor cover as it comes off the retaining threads is visible relative to the Accurate CT sensor. Since the Accurate CT sensor is the farthest sensor from SCAMP's center it is the most likely sensor to be damaged when removing the sensor cover. |
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| Screw the sensor guard into place. Use a small cable tie or bit of dental floss to tie one of the guard's legs to one of the sensor seal nuts bases. This will prevent the unscrewing of the guard during a SCAMP deployment. Should the guard come unscrewed the retrieval cable can slip loose and the SCAMP will be lost. The sensor guards screw on tightly, but this extra precaution is low-cost insurance. The picture displays an older version of this guard. |   |
| Move the float assembly back against the sensor guard base. |
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| Move the cable loop and the 5151 float retainer ring back against the float. Tighten the thumbscrew on the float retainer ring. |
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| Install the drag assembly and tighten the thumbscrews. Be sure that the thumbscrews find the groove in the end sleeve on the SCAMP. If the SCAMP slips from the drag assembly, then it can be lost. |
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| Place the SCAMP in the SCAMP stand with the sensors in the water contained by the bucket. The tent for the computer is not shown in the photos. |
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| Insert the drag plate wing
retainer pin located on the cable into the drag plate arms. Insure that the I/O connector cover is securely in place over the I/O connector. Water must not enter this connector!! |
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Mission Definition
You must program SCAMP to implement the desired profile. Once programmed, SCAMP will implement the profile over and over with data from each profile stored separately in SCAMP’s memory. Missions are defined by the following steps:
Establish communication with the SCAMP.
Select the Mission tab, shown below.
Define Starting Conditions for Data Recording. The conditions you define are ‘OR’d by SCAMP for the purposes of determining when to begin a profile. SCAMP will begin a profile when it determines that any one of the conditions you define are true. You must carefully consider the definitions you make here.
In an upwards profile, SCAMP must sink to the Begin Depth depth before it releases its weight and begins its ascent. You must provide Begin Delay time for SCAMP to be deployed and reach the desired depth. You can supply substantially more Begin Delay time, but then if SCAMP reaches the bottom before it reaches the Begin Depth you will have to wait this entire time or loose the profile by hauling SCAMP back. Also, SCAMP will not begin a new profile until either you connect it to the host computer or it ends the current profile so you will be faced with waiting out the Begin Delay time or connecting SCAMP.
Define Ending Conditions for Data Recording. At the time the profile
begins scanning and operates its release motor, releasing the attached weight. Thereafter
SCAMP ascends while collecting data. You should define Acquire Scans with sufficient scans
to collect data over the length of the water column. SCAMP scans at 100 scans per second
and nominally travels at 10 cm/second giving a nominal 1000 scans per meter. Allow extra
scans to cover uncertainties in depth and SCAMP travel rate. Disconnect SCAMP from the host computer and place the I/O cover onto the
I/O connector prior to profiling.
Profiling
SCAMP will acquire multiple profiles without uploading of data or re-definition of missions. Between profiles SCAMP enters a low power ‘sleep’ state to conserve batteries. Prior to each profile SCAMP must be ‘awakened’. After SCAMP is awake it can be placed into the water and perform its mission. (Note that SCAMP will not acquire a profile if connected to the host computer!)
Profiles are implemented with the following steps:
Place a finger against the release screw. Hold the Start Magnet near the SCAMP, about half way between the ends. Magnet should be alligned with the Accurate CT sensor. When SCAMP senses the magnet it will immediately rotate the release screw for a brief period. The magnet should be removed at this time. SCAMP reviews its internal state to determine if sufficient battery and memory resources exist to acquire the impending profile. If insufficient resources are available SCAMP will return to sleep mode. if sufficient resources are available and after about 2 seconds, SCAMP will operate its release motor twice briefly. At this time SCAMP will define the current pressure as zero depth and begin evaluating starting conditions for data recording as described in the section above. (Note that since SCAMP's pressure transducer is located at end opposite SCAMP's sensors, sensor zero depth will be different and must be adjusted by the customer's software.) Once it begins evaluating start conditions, SCAMP must complete a profile before it will return to the sleep state. (See the Aborting a Profile section if a profile must be aborted.)
| Connect a weight to the SCAMP by placing the wire loop over the release screw and post, with the collar inward along the post. Move the loop to the base of the lead screw. Pull the wire to test that the loop will not slip off. Place the weight on the underside (presently in the upwards position with the SCAMP on the stand) of the drag plate. |
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| Lift the SCAMP from the stand while supporting the expendable weight. Hold the SCAMP with the sensors up and let the weight hang down free. The weight is not shown in the picture. |
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| Place the SCAMP in
the water with the hinged side of the drag plate
away from the boat. This is important since the SCAMP will sink at a
45 degree angle toward the hinged side of the drag plate. Release the SCAMP and pay out
the cable as it sinks. The SCAMP must be free of cable tension as it travels in the water column. You must pay out sufficient retrieval line to prevent cable tension as the SCAMP travels away from the boat. Also, in windy conditions the boat will be blown away from the SCAMP and the retrieval line must be paid out to compensate. You may attempt to hold station with the boat, but you risk cutting the retrieval line with the propeller. This operation takes some practice and people new to SCAMPing are advised to practice on calm days first. |
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When you see the SCAMP, (the SCAMP may be hard to see on windy days), or when sufficient
time has elapsed for the SCAMP to sink and return to the surface, recover the SCAMP by
hauling it back with the cable. Wind it onto the reel in the reverse manner from the
way it was unwound. First, give a gentle tug on the retrieval line to pull the pin holding
the drag unit wings allowing these to fold back. This will make hauling the SCAMP
back much easier.
| When the SCAMP is alongside the boat, first grasp the retrieval line within 1 meter of the SCAMP. The retrieval line is reinforced in this area. Lift the SCAMP by this retrieval line or the sensor guard (do not touch the sensors) until you can grasp the SCAMP tube below the floats. Lift it into the boat. Once retrieved, then place the SCAMP again in the stand with the sensors in the bucket of water. |
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At this time you may again conduct a profile by repeating the steps in this Profiling section. Alternately, you may upload SCAMP’s data.
A final note: SCAMP profile files are named with the time that
SCAMP determined a starting condition became true and began the profile.
