Buckleys BATHYCORROMETER - Calibration; Electronics Calibration Check; Test Procedure Using

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Buckleys (UVRAL) Ltd. Range Road, Hythe, Kent. United Kingdom. CT21 6HG.
Tel:- +44 (0) 1303 260127/8 Fax:- +44 (0) 1303 262115
8.0 Calibration
There are two parts of a BCM that affect calibration. Firstly the electronics and
secondly the Ag/AgCl reference Electrode.
8.1 Electronics Calibration Check
The Electronics in the BCM can be checked with the aid of a BCM Checker (Not
Supplied), this, when connected to the BCM, produces an precision voltage of 1.990V
DC which can be compared with the BCM’s reading. This is just a check as the
electronics are contained inside the pressure housing and cannot be adjusted without
breaking the seal. Undoing the pressure housing voids the warranty. The unit should be
returned to Buckleys if the reading on the BCM is more than ± 10mV out from the
1.990V test voltage. Check that it is not the BCM Checker that is at fault first.
8.2 Test Procedure using screw on Calomel Reference Electrode
1. Unscrew the white Delrin Probe Cone.
2. Smear the “O” ring on the Calomel Reference Electrode with a little Silicone
Grease.
3. Screw the Calomel Reference Electrode onto the threaded Tie Rod, ensuring a
tight connection and correct seating of the “O” ring.
4. Fit the Blanking Plug and immerse the BCM in Seawater, ensure that the level
covers the Red Nose Cone.
5. Allow the Electrode to reach a stable potential (10 to 15 minutes).
6. The voltage difference between the Calomel Electrode and the internal
Silver/Silver Chloride Electrode can be read directly off the digital display on the
BCM.
Note 1:
The values recorded for the Silver/Silver Chloride Electrode are dependent upon
the Salinity and Temperature of the Seawater at the time of measurement.
Note 2:
The Det Norske Veritas (D.N.V.) specification “Guidelines in Potential
Measurement on steel structures” gives the potential value for the Ag/AgCl
Electrode as -4mV ± 5mV. This is with the Ag/AgCl Electrode connected to the
Negative terminal of the voltmeter, however in the BCM the Ag/AgCl Electrode
is connected to the Positive terminal in accordance with conventional standards.
To comply with the D.N.V. specification the value for the Ag/AgCl Electrode will