Wet Labs ac-s User manual

ac-s User’s Guide (ac-s) Revision F 9 Feb. 2006
Spectral Absorption and
Attenuation Meter
ac-s
User’s Guide
WET Labs, Inc.
P.O. Box 518
Philomath, OR 97370
541 929-5650
www.wetlabs.com

ac-s User’s Guide (ac-s) Revision F 9 Feb. 2006
Attention!
Return Policy for Instruments with Anti-fouling Treatment
WET Labs cannot accept instruments for servicing or repair that
are treated with anti-fouling compound(s). This includes but is not
limited to tri-butyl tin (TBT), marine anti-fouling paint, ablative
coatings, etc.
Please ensure any anti-fouling treatment has been removed prior to
returning instruments to WET Labs for service or repair.

ac-s User’s Guide (ac-s) Revision F 9 Feb. 2006
ac-s Warranty
This unit is guaranteed against defects in materials and workmanship for one year from
the original date of purchase. Warranty is void if the factory determines the unit was
subjected to abuse or neglect beyond the normal wear and tear of field deployment, or in
the event the pressure housing has been opened by the customer.
To return the instrument, contact WET Labs for a Return Merchandise Authorization
(RMA) and ship in the original container. WET Labs is not responsible for damage to
instruments during the return shipment to the factory. WET Labs will supply all
replacement parts and labor and pay for return via 3rd day air shipping in honoring this
warranty.
Shipping Requirements for Warranty and Out-of-warranty Instruments
1. Please retain the original shipping material. We design the shipping container to
meet stringent shipping and insurance requirements, and to keep your meter
functional.
2. To avoid additional repackaging charges, use the original box (or WET Labs-
approved container) with its custom-cut packing foam and anti-static bag to return
the instrument.
• If using alternative container, use at least 2 in. of foam (NOT bubble wrap or
Styrofoam “peanuts”) to fully surround the instrument.
• Minimum repacking charge for ac meters: $240.00.
3. Clearly mark the RMA number on the outside of your shipping container and on
all packing lists.
4. Return instruments using 3rd day air shipping or better: do not ship via ground.

ac-s User’s Guide (ac-s) Revision F 9 Feb. 2006 i
Table of Contents
1. Instrument Setup and Testing.........................................................................1
1.1 Installing WETView ................................................................................................ 1
1.2 Bench Testing .......................................................................................................... 2
1.3 Air Tracking............................................................................................................. 3
1.4 Cleaning ...................................................................................................................3
1.5 System Requirements............................................................................................... 5
2. Operation...........................................................................................................6
2.1 Basic Power On........................................................................................................ 6
2.2 Mounting and Deploying the Meter......................................................................... 6
2.3 Data Collection ........................................................................................................ 9
2.4 Care and Maintenance............................................................................................ 10
3. Data Processing..............................................................................................11
3.1 Analog Acquisition ................................................................................................ 11
3.2 Analog-to-Digital Conversion ............................................................................... 11
3.3 Digital Processing and Data Output....................................................................... 11
3.4 Data Format ........................................................................................................... 11
3.5 Post Processing ...................................................................................................... 11
3.6 Temperature-dependent Absorption Correction .................................................... 13
3.7 Scattering Correction ............................................................................................. 14
4. Calibration and Characterization...................................................................15
4.1 Temperature Correction......................................................................................... 15
4.2 Precision................................................................................................................. 15
4.3 Absolute Calibration .............................................................................................. 16
4.4 Linearity and Dynamic Range ............................................................................... 16
4.5 Air Calibration and Tracking................................................................................. 16
5. Specifications .................................................................................................19
5.1 Connectors ............................................................................................................. 19
5.2 Power Requirements .............................................................................................. 21
6. Technical Reference.......................................................................................22
6.1 Mechanical............................................................................................................. 22
6.2 Optics ..................................................................................................................... 22
6.3 Electronics.............................................................................................................. 25
6.4 Signal Processing................................................................................................... 25
Appendix A: Data Record Format......................................................................28
Primary Processing ............................................................................................................. 30
Appendix B: Pressure Sensor Use and Care....................................................33
Appendix C: Common Mode A/C Induced Noise .............................................34

ac-s User’s Guide (ac-s) Revision F 9 Feb. 2006 1
1. Instrument Setup and Testing
This section provides an introduction to the ac-s and describes how to set up and perform air
tracking and bench testing prior to deploying the ac-s.
The ac-s is delivered in a sturdy wooden shipping container with the following components:
• ac-s, with one absorption flow tube and one attenuation flow tube
• four flow sleeves
• four protective black plastic caps
• dummy plug with lock collar
• this manual
• WETView User’s Guide
• additional reference: ac-9 Protocol Document
• WETView software and instrument-specific calibration information
• Ten-foot test cable
• double “Y” de-bubbler tubing
• stainless steel intake screens
Familiarize yourself with the ac-s: remove the black plastic flow tubes by grasping the
flow tube sleeves and sliding them away from the ends of the flow tube (toward the
middle of the flow tube). You only have to slide the collars about ½ in. to unlock the flow
tube from its fixed position. The flow tube will lift out, exposing the transmitter and
detector windows on the lower and upper flanges respectively. Observe the flow tubes.
The attenuation tube is different from the absorption tube. Its flow chamber is plastic and
the two sleeves on the tube are identical. This tube installs on the “c” side of the
instrument (the side with the identical looking windows). The “c” tube has no “up or
down” orientation. The absorption tube is lined with a quartz tube and one of the two
sleeves is flat on top (the lip present on all the other sleeves is missing). This tube installs
on the “a” side of the instrument, which can be identified by the “a” detector on the upper
flange and is the only window, which is clearly different from the other three. The flat
flow tube sleeve goes on this detector.
You may want to mark the tubes and their orientation with tape or marking pen before
using the instrument at sea so there is no confusion upon reinstalling the tubes after
cleaning the optics. Reinstall the flow tubes before bench testing your instrument. If you
have removed the plastic caps from the stainless nozzles, replace them at this time.
1.1 Installing WETView
WETView displays data produced by WET Labs ac meters. It runs on PC-compatible
computers with at least 16 Mb of memory and 3 Mb free hard disk space running
Windows-95 or later operating system.
1. Insert the WETView CD in the host computer.
2. Double-click on the SETUP.EXE icon. Setup will guide you through the rest of the
installation process.

2 ac-s User’s Guide (ac-s) Revision F 9 Feb. 2006
When installed, the following files should be on the hard disk: WETVIEW.EXE,
WETVIEW.UIR, ACSXXX.DEV, AIRXXYYY.CAL. The .DEV and .CAL files are the
calibration files for your particular instrument. They are not installed by setup and will
need to be copied to the hard drive manually.
Caution
If you have old device files from previous calibrations, you should rename them or
archive them in a different directory so that they will not be overwritten.
1.2 Bench Testing
The following items are needed to bench test the ac-s:
• A clean, solid lab table or work bench
• The ac-s with 10-foot test cable (or sea cable)
• A 10–35 volt power supply (the ac-s requires 10–35 VDC)
• A PC with WETView installed.
1. Connect the test cable to COMM1–COMM4 of the computer. Connect the power
leads to the power supply. The black lead is the V+ lead. Before connecting the cable
to the instrument, use a multimeter to check the input power.
2. Connect the ground probe to pin 1 on the pigtail connector (the center pin as you are
looking into the connector). Connect the hot probe to pin 4 (Figure 4). You should
measure the power supply voltage across these two pins.
3. Turn the power supply off.
4. Connect the pigtail to the instrument. Push the connector straight on to avoid
damaging the pins. Apply power to the instrument and allow it to begin warming up.
5. Run WETView. When the interface is displayed, you will need to provide a .DEV file
name. Click on the <O> button in the center top of the screen or choose “Open
Device File” from the File Menu at the top left of the screen. The program will ask
you to choose the proper COMM port. Select COMM1 through COMM4 as
appropriate. Note that WETView supports COMM1 through COMM4 only.
6. Click on the center button or <F1> to start displaying data. After 5–10 seconds,
tabular data should be displayed on the right side of the screen. A real time graph will
begin to develop, depending on the graph parameters set at the time. Refer to the
WETView User’s Guide for details of running the WETView software.
7. After a short time, again click on the center button that will stop the data collection
and ask for a file name to apply to the data if you should want to archive it. Press ESC
if you do not want to save the data. To quit the program, choose QUIT from the File
menu. At this point you have successfully completed a bench test of the instrument.