NZQA registered unit standard
28080 version 1
Page 1 of 4
Title
Demonstrate knowledge of liquid analytical measurement systems
Level
4
Credits
Purpose
3
This unit standard covers principles of industrial liquid analytical
measurements and the operation of systems used to perform
the measurements.
People credited with this unit standard are able to demonstrate
knowledge of:
 pH measurement;
 conductivity measurement;
 dissolved oxygen measurement;
 consistency and viscosity measurement;
 density measurement ; and
 analytical sampling systems.
Classification
Industrial Measurement and Control > Industrial Measurement
and Control - Theory
Available grade
Achieved
Explanatory note
1
Definition
e.m.f. – electro-motive force.
Outcomes and evidence requirements
Outcome 1
Demonstrate knowledge of pH measurement.
Evidence requirements
1.1
Define the term pH and its associated scale.
Range
1.2
Describe components of a pH measuring system.
Range
1.3
positive hydrogen ions, 14 alkaline, 3 acidic, 7 neutral, log scale.
reference electrode, measuring electrode, temperature
compensation, very high input impedance amplifier.
Describe the operating principles of the pH measuring system.
The Skills Organisation
SSB Code 100401
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
1.4
Identify calibration methods for pH measuring systems.
Range
1.5
28080 version 1
Page 2 of 4
buffer solution, backing off unwanted e.m.f.s.
Identify problems associated with pH measuring systems.
Range
electrode cleaning, ultrasonic, mechanical wiping, lead wire
connections, probe failure, earthing.
Outcome 2
Demonstrate knowledge of conductivity measurement.
Evidence requirements
2.1
Describe principles of conductivity measurement.
Range
2.2
Define factors to be taken into account when making conductivity
measurements.
Range
2.3
siemens, micro mho, electrolyte.
non-linear solution strengths, temperature compensation, probe
constant.
Describe calibration techniques.
Range
amplifier decade box injection, dedicated test equipment, standard
solutions.
Outcome 3
Demonstrate knowledge of dissolved oxygen measurement.
Evidence requirements
3.1
Describe principles of dissolved oxygen measurement.
Range
galvanic cell, polarographic cell.
3.2
Explain air exposure at valve glands, and its prevention, in relation to making
dissolved oxygen measurements.
3.3
Describe calibration techniques.
Range
The Skills Organisation
SSB Code 100401
transmitter adjustment, sample 5% sodium sulphite, water
saturated air.
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
28080 version 1
Page 3 of 4
Outcome 4
Demonstrate knowledge of consistency and viscosity measurement.
Evidence requirements
4.1
Describe types and uses of consistency transmitters.
Range
4.2
pulp stock, shear forces, force balance, blade type, rotating blade,
optical.
Describe types and uses of viscosity transmitters.
Range
oil, liquid, rotational, capillary, float.
Outcome 5
Demonstrate knowledge of density measurement.
Evidence requirements
5.1
Describe methods of density measurement and state their applications.
Range
differential pressure, displacement transmitter, weight of fixed
volume, nuclear radiation, refractometer, ultrasonic, vibrating
mass.
Outcome 6
Demonstrate knowledge of analytical sampling systems.
Evidence requirements
6.1
State steps to obtain and process an analytical sample and show in a block
diagram.
6.2
State the components of a sampling system.
Range
may include but is not limited to – pumps, valves, flowmeters and
switches, filters, phase separating devices, heat exchangers.
Replacement information
This unit standard and unit standard 28081 replaced unit
standard 2641.
Planned review date
31 December 2017
The Skills Organisation
SSB Code 100401
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
28080 version 1
Page 4 of 4
Status information and last date for assessment for superseded versions
Process
Version Date
Last Date for Assessment
Registration
1
28 November 2013
N/A
Consent and Moderation Requirements (CMR) reference
0003
This CMR can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.
Please note
Providers must be granted consent to assess against standards (accredited) by NZQA,
before they can report credits from assessment against unit standards or deliver courses
of study leading to that assessment.
Industry Training Organisations must be granted consent to assess against standards by
NZQA before they can register credits from assessment against unit standards.
Providers and Industry Training Organisations, which have been granted consent and
which are assessing against unit standards must engage with the moderation system that
applies to those standards.
Requirements for consent to assess and an outline of the moderation system that applies
to this standard are outlined in the Consent and Moderation Requirements (CMR). The
CMR also includes useful information about special requirements for organisations wishing
to develop education and training programmes, such as minimum qualifications for tutors
and assessors, and special resource requirements.
Comments on this unit standard
Please contact The Skills Organisation reviewcomments@skills.org.nz if you wish to
suggest changes to the content of this unit standard.
The Skills Organisation
SSB Code 100401
 New Zealand Qualifications Authority 2016