AC-S In-Situ Spectrophotometer

ac-s In-Situ Spectrophotometer

Based on the highly successful ac-9, the ac-spectra (ac-s) offers almost an order of magnitude increase in spectral resolution of in-situ absorption and beam attenuation. The 4 nm resolution allows for spectral "fingerprinting" and deconvolution analysis.

The ac-s features a proven flow-through system, compact size, and excellent stability. With 80 (+/-5) wavelength outputs from 400–730 nm, the 4 nm resolution allows for spectral “fingerprinting” and deconvolution analysis. The ac-s employs a 25-cm pathlength for effective measurement of the cleanest natural waters.


Diameter10.4 cm
Length79 cm
Weight in air5.9 kg
Weight in water0.8 kg


Input voltage10–35 VDC
OutputRS232, RS485
Current draw0.83 A @ 12 V nominal


Temperature range0–30 o C
Depth rating500 m


Spectral range400–730 nm


Bandpass (FWHM), nm

400: 10–18
450: 10–16
550: 10–15
650: 10–18
730: 10–25
Pathlength, cm10 or 25
Beam cross-section8 mm dia. (nominal)
Linear dispersion6–7.0 nm/mm
Resolution4 nm
Precision, 400 to 449 nm+/-0.003 m-1 typ., 0.006 m-1 max @ 1 Hz
+/-0.005 m-1 typ., 0.012 m-1 max @ 4 Hz
Precision, 450 to 730 nm+/-0.0005 m-1 typ., 0.0015 m-1 max @ 1 Hz
+/-0.001 m-1 typ., 0.003 m-1 max @ 4 Hz
Accuracy0.001–10 m-1


Specifications are subject to change without notice.
Released July 7, 2014 for Windows XP/Vista/7

Host software for ac-s

Download WETView 7 7

Released June 19, 2012 for Windows XP/Vista/7
Released March 3, 2014 for Windows XP/Vista/7
Product Datasheet

ac-s datasheet

Monday, December 5, 2016

ac-s Product Drawing

Tuesday, February 12, 2013
Product Manual

ac Protocol Document

Tuesday, December 4, 2012
Product Manual

Compass Software User Manual

Monday, July 7, 2014
Product Manual

Compass Software Quickstart

Monday, July 7, 2014
Product Manual

ac-s user manual

Thursday, April 27, 2017
Product Manual

WETView7 Software Manual

Thursday, June 21, 2012
Technical Note

Cable and Bulkhead Connector Maintenance

Thursday, March 9, 2017
Technical Note

Instrument Voltage Ranges (in VDC)

Thursday, June 21, 2012

What should I use to lubricate bulkhead connectors?

WET Labs recommends keeping the connectors on your meter lubricated using a good quality silicone spray lubricant, such as 3M Silicone Spray or Loctite 8021 spray. These can be purchased at your local hardware store. Avoid silicone grease. It is messy and attracts contaminants. 

Do not use WD-40. It will destroy connectors.

Do you want WET Labs to review your data?

In order for data questions to be answered in an efficient manner, WET Labs requests:

-  The serial number of the instrument data in question. The most current calibration information
can be verified and the instrument settings upon delivery can be checked.

-  Description of the deployment configuration. Questions to consider:

  •   What are the current instrument settings?
  •   What is the instrument orientation?
  •   Are there possible obstructions?
  •   Is it being used in a mooring, a profiler, or being towed?
  •   What were the deployment date and geographical location?
  •   How far into the deployment was the problem seen?
  •   What power supply and cabling are being used?
  •   What was the instrument condition during the last field service or retrieval?
  •   Do you have any pictures?

-  Raw data files of the physical data in question

  •   examples of good raw data.
  •   examples of questionable raw data .

-  Information about how the raw data was processed.