WorkHorse H-ADCP Operation Manual
May
2015
EAR-Controlled Technology Subject to Restrictions Contained on the Cover Page.
Page 45
Maintenance Schedule
To ensure that you continue to receive optimal results from your Teledyne RD Instruments product(s),
TRDI recommends that every H-ADCP be returned to our factory for an inspection every two to three
years. We’ll provide your unit with a thorough multi-point inspection, and let you know if any refurbish-
ment services are required to properly maintain the unit. To learn more about this service, please
Calibration Items
Use the following calibration schedule:
Item
TRDI Recommended Period
Transducer Beam Angle
TRDI recommends returning the H-ADCP every two to three years for verification of velocity accuracy
Pitch & Roll (Tilt)
TRDI recommends returning the H-ADCP every two to three years for Factory calibration
Temperature (Factory)
Pressure Sensor (Factory)
Heading (Field Pre-Deploy)
Field Compass Calibration (AF) performed prior to each deployment (see
Heading (Field Post-Deploy)
Field Compass Verification (AX) performed post each deployment (see
Compass Calibration Verification
Pressure sensor and compass drift effects will accumulate over time. TRDI recommends a
factory calibration be done every two to three years. The longer you wait between factory
calibrations, the more error (due to drift) you can expect to have.
For example, the pressure sensor has an initial accuracy spec of ±0.25%, and a long-term drift
spec of ±0.11%. Most of the 0.11% drift will occur in the first 12 months of operation. The
fluxgate compasses accumulate an error of approximately 1% over a year.
Maintenance Items
Inspect the H-ADCP to spot problems:
Item
TRDI Recommended Period
Transducer Beams
The urethane coating is important to H-ADCP watertight integrity. Many users are not familiar with the early
signs of urethane failure. The primary damage to the urethane is from bio-fouling and long exposure to the
water and sun. Damage occurs on the surface of the urethane and at the edge where the urethane bonds to
the cups. Mishandling, chemicals, abrasive cleaners and excessive depth pressures can also damage the trans-
ducer ceramics or urethane coating.
Before each deployment, check the urethane coating on the transducer faces for dents, chipping, peeling,
urethane shrinkage, hairline cracks and damage that may affect watertight integrity or transducer operation
(see Figure 20).
Based on experience, TRDI knows that most systems need to have the urethane inspected after three to five
years of field use; shorter periods may be required depending on marine growth.
O-rings
O-rings should be replaced whenever the system is opened and BEFORE they are showing any signs of wear
and tear. Replace the end-cap O-ring each time the end-cap is removed.
All O-rings should be replaced every one to two years maximum.
Housing and End Cap
Inspect for damage and replace as needed before each deployment.
Inspect the paint on the end-cap, housing, and transducer assemblies for corrosion, scratches, cracks, abra-
sions, paint blisters, exposed metal (silver-colored aluminum), exposed anodize (black or dark green), and
exposed primer (yellow).
Be critical in your judgment; the useful life of the H-ADCP depends on it.
See
tective Coating Inspection and Repair
for details.