Dwyer PUB User Manual

Series PUB Portable Ultrasonic Flowmeter Kit
Installation and Operating Instructions

Bulletin F-PUB

©Copyright 2012 Dwyer Instruments, Inc. Printed in USA 9/12 Version 1.0

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, USA

Phone: [phone] www.dwyer-inst.com

Fax: [phone] email: [e-mail]

Table of Contents

1: General Description 1

1.1 Introduction 1

1.2 Principles of Operation 2

1.3 Supplied Hardware 3

1.4 PUB Instrument 4

1.4.1 Connectors 4

1.4.2 Keypad 5

1.4.3 Power supply and battery charging 6

1.5 Transducers 6

2: Installation 7

2.1 Transducer Positioning 7

2.2 Transducer Attachment 8

2.2.1 Preparation 8

2.2.2 Attaching the transducer holders 8

2.2.3 Fitting the transducers 9

3: Operating Procedures 10

3.1 Setting-up the Instrument 11

3.1.1 Using the instrument for the first time 11

3.1.2 Enabling/disabling the backlight 12

3.2 Using the Quick Start Menu 13

3.3 Using the System at a Regularly Monitored Location 16

3.4 Managing Named Sites 18

3.4.1 Setting up a new site 18

3.4.2 Changing a site name 19

3.5 Instrument Calibration 19

3.5.1 Adjusting the zero cut-off 19

3.5.2 Adjusting the set zero flow offset 19

3.5.3 Adjusting the calibration factor 20

3.5.4 Adjusting the roughness factor 21

3.5.5 Adjusting the damping factor 22

3.6 Performing Monitoring Functions 23

3.6.1 How to measure totalized flows (manually) 23

3.6.2 How to stop the totalizer temporarily 24

I

3.7 Configuring the Current / Pulse Output 24

3.7.1 Current output 24

3.7.2 Pulse output 26

4: Maintenance & Repair 29

4.1 Warranty / Return 29

5: Troubleshooting 30

5.1 Overview 30

5.2 General Troubleshooting Procedure 31

5.3 Warning & Status Messages 32

5.4 Test Block 34

5.5 Microprocessor Reset Facility 35

5.6 Diagnostics Display 35

6: Specification 37

II

1: General Description

1.1 Introduction

This manual describes the operation of the Dwyer PUB portable flowmeter. The flowmeter is desi g ne d to work
with clamp-on transducers to enable the flow of a liquid within a closed pipe to be measured accurately without
needing to insert any mechanical parts through the pipe wall or protrude into the flow system.

Using ultrasonic transit time techniques, the PUB is controlled by a micro-processor system which contains a
wide range of data that enables it to be used with pipes with an outside diameter ranging from 0.5 to 40 inches
(13 to 1000 mm), depending on model, and constructed of almost any material. The instrument will also operate
over a wide range of fluid temperatures.

The PUB series comprises two models which are identical in operation but designed to be used with a different
range of pipe diameters. The PUB-A can be used with pipes in the range 0.5 to 4.5
the PUB-B with pipes in the range 2 to 40 inches (50.8 to 1016 mm).

Easy to operate, the PUB standard features are:

• Large, easy to read graphic display with backlighting.

• Simple to follow dual function keypad.

• Simple ‘Quick Start’ set up procedure.

• Continuous signal monitoring.

• Pulse output volumetric or frequency).

• 4 to 20 mA, 0 to 20 mA, or 0 to 16 mA output.

• Rechargeable battery.

• Battery management.

• Diagnostics.

Volumetric flow rates are displayed in L/h, L/min, L/sec, gal/min, gal/h, USgals/min, USgals/h, Barrel/h, Barrel/
day, m³/s, m³/min, m³/h. Linear velocity is displayed in meters or feet per second.

When operating in the ‘Flow Reading’ mode the total volumes, both positive and negative, are displayed up to a
maximum 12-digit number.

The flowmeter can be used to measure clean liquids or oils that have less than 3% by volume of particulate
content. Cloudy liquids such as river water and effluent can be measured along with cleaner liquids such as
demineralized water.

Typical PUB applications include:

• River water.

• Seawater.

• Potable water.

• Demineralized water.

• Treated water.

1: General Description

inches (12.7 to 114 mm) and

1

1: General Description

Fluid flow

Fluid flow

Fluid flow

Fluid flow

Fluid flow

U

U

U

U

D

D

D

Separation

Distance

Separation

Distance

Separation

Distance

Separation

Distance

Reflex mode

Reflex mode (double bounce)

Reflex mode (triple bounce)

Diagonal mode

This is the mode most commonly used.
The two transducers (U & D) are attached
to the pipe in line with each other and the
signals passing between them are reflected
by the opposite pipe wall.
The separation distance is calculated by
the instrument in response to entered data
concerning the pipe and fluid characteristics.

In this mode the separation distance is
calculated to give a double bounce. This is
most likely to occur if the pipe diameter is
so small that the calculated reflex mode
separation distance would be impractical
for the transducers in use.

This illustration goes one step further to show
a triple bounce situation. This would normally
apply when working with very small pipes
relative to the transducer range.

This mode might be selected by the
instrument where relatively large pipes are
concerned. In this mode the transducers are
located on opposite sides of the pipe but the
separation distance is still critical in order
for the signals to be received correctly.

Upstream

transducer

1.2 Principles of Operation

When ultrasound is transmitted through a liquid, the speed at which the sound travels through the liquid is
accelerated slightly if it is transmitted in the same direction as the liquid flow, and decelerated slightly if
transmitted against it. The difference in time taken by the sound waves to travel the same distance but in opposite
directions is therefore directly proportional to the flow velocity of the liquid.

The PUB system employs two ultrasonic transducers attached to the pipe carrying the liquid and compares the
time taken to transmit an ultrasound signal in each direction. If the sound characteristics of the fluid are known,
the PUB microprocessor can use the results of the transit time calculations to compute the fluid flow velocity.
Once the flow velocity is known the volumetric flow can be easily calculated for a given pipe diameter. The PUB
system can be set up to operate in one of four modes, determined mainly by the pipe diameter and the transducer
set in use. The diagram below illustrates the importance of applying the correct separation distance between the
transducers to obtain the strongest signal.

Figure 1.1 Operating modes

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1.3 Supplied Hardware

4 to 20 mA /

Test Block

Power Supply

Pulse Output

Cable

Transducer Cables (x2)

Chains (x2)

Transducer

Transducers
(Sensors x2)

Ultrasonic Couplant

Ruled Separation bar (x2)

PUB Instrument

(Batt. Charger)

Holders (x2)

The PUB equipment is supplied in a rugged polypropylene carrying case fitted with a foam insert to give added
protection for transportation. The supplied components are shown in Figure 1.2.

1: General Description

Figure 1.2 Standard PUB equipment

3

Standard equipment

• PUB instrument with backlit graphic display.

• Power supply - with UK, US, European adaptors. 110/240 VAC.

• 4 to 20 mA/Pulse Output cable.

• 2 lengths of chain.

• Test block.

• Transducer cables (x2) 79 inches (2m) long.

• Transducer set (x2) – type ‘A’ or type ‘B’ depending on model.

• Set of transducer holders used for mounting the transducers.

• Ruled separation bar (2-piece).

• Ultrasonic couplant with syringe dispenser used when mounting the transducers.

• Manual.

1: General Description

Keypad

LCD Display

Battery Charger

4-20mA / Pulse Output Transducer Cables

Reset pin-hole

1.4 PUB Instrument

The PUB is a microprocessor controlled instrument operated through a menu system using an inbuilt LCD display
and keypad. It can be used to display the instantaneous fluid flow rate or velocity, together with totalized values.

The instrument can also provide a variable current or variable ‘pulse’ (volumetric of frequency) output that is
proportional to the detected flow rate. This output can be calibrated to suit a particular flow range and used with a
range of external interface devices such as those found in building management or site monitoring systems.

1.4.1 Connectors

Figure 1.3 Instrument details

Transducer connections

The transducers are connected to two color-coded miniature coaxial sockets located on the top of the instrument.
Using the red/blue connector cables provided, the upstream transducer should always be connected to the RED
socket and the downstream transducer to the BLUE one for a positive flow reading. It is safe to connect or
disconnect the cable while the instrument is switched on.

4 to 20 mA and Pulse output connection

The 4 to 20mA / ‘pulse’ output cable should be connected to the green 7-pin connector on the top of the
flowmeter, as shown in Figure 1.3. A single cable that can be adapted for use for either of these output functions
is included in the PUB kit. The ‘tails’ on the free end of the cable must be terminated to suit the intended
application.

Red – 4 to 20 mA positive
Black – 4 to 20 mA negative
White – Pulse output
Green – Pulse return
Thick Black – Cable screen

Battery charger connection

The supplied battery charger is connected to the instrument by means of the gray 2-pin connector on the bottom
of the unit, as shown in Figure 1.3.

Note: The above connectors have different key-ways to prevent incorrect cable connection.

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1.4.2 Keypad

ON/OFF

Scroll UP

ENTER

Scroll DOWN

Numerical keypad

Scroll LEFT

Scroll RIGHT

with dual function keys

(SELECT)

The instrument is configured and controlled via a 16-key tactile membrane keypad, as shown in Figure 1.4.

ON/OFF Key

The ON/OFF key is shown on the top left of the keypad. When turned ON an initialization screen is displayed on
the LCD showing the instrument’s serial number and software revision. Once this appears, the instrument can be
started by pressing the ENTER key once – the initialization screen is then replaced by a MAIN MENU which
provides access to the remaining functions.

Menus and the menu selection keys

The PUB menus are arranged hierarchally with the MAIN MENU being at the top level. Menu navigation is
achieved by three keys on the right hand side of the keypad which are used to scroll UP and DOWN a menu list and
SELECT a menu item. When scrolling through a menu, an arrow-shaped cursor moves up and down the left hand
side of the screen to indicate the active menu choice which can then be selected by pressing the ENTER
(SELECT) key.

Some menus have more options than can be shown on the screen at the same time, in which case the
‘overflowed’ choices can be brought into view by continuing to scroll DOWN beyond the bottom visible item. Menus
generally ‘loop around’ if you scroll beyond the first or last items.

If you select Exit on any menu it usually takes you back up one level in the menu hierarchy, but in some cases it
may go directly to the ‘Flow Reading’ screen.

Some screens require you to move the cursor left and right along the display as well as up and down. This is
achieved using keys 5 (scroll LEFT) and 6 (scroll RIGHT).

Dual function numerical keypad

The block of keys shown in the center of the keypad in Figure 1.4 are dual function keys. They can be used to
enter straight-forward numerical data, select the displayed flow units, or provide quick access to frequently
required control menus.

1: General Description

Figure 1.4 Keypad

Note: Some of the features accessed by these keys are restricted in the PUB model range. An “Option not

available” message is displayed if you select a restricted function.

5

1: General Description

1.4.3 Power supply and battery charging

Operating power is provided by an internal battery that can be charged from the utility supply using the supplied
external charger. When you first receive the unit you must put the battery on charge for a minimum of 6.5hrs
before use. A fully charged battery will power the instrument for up to 20 hours depending on the output utilization
and backlight usage.

The backlight can be selected to be either permanently OFF, illuminated for 10 seconds, 30 seconds or 1 minute
every time a key is pressed, or permanently ON – as configured in the Setup Instrument menu. If the backlight
is active continuously it will reduce the available battery operating time to 8hrs. Similarly, if the 4 to 20 mA output
is used constantly at 20 mA, the battery life would reduce by 50%. It is therefore beneficial to turn off the backlight
and 4 to 20 mA output facilities when they are not required.

When the instrument is operating in the ‘Flow Reading’ mode, the percentage battery charge level is displayed
symbolically on the LCD screen. A warning message is triggered if the charge falls to approximately 30%, at
which point there is up to four hours of battery operation remaining, depending on usage. The battery can be
charged both while the instrument is in use or when switched off. The instrument’s internal data is stored in non­volatile memory and will not be lost even if the battery discharges completely.

Key Point: The battery is not a user-changeable item. The instrument must be returned
to your distributor if the battery needs replacing.

Key Point: Only use the supplied charger, or special adaptor lead. Failure to comply
with this will invalidate your warranty.

1.5 Transducers

Different transducer sets are provided with the PUB-A and PUB-B models and are not interchangeable.

Key Point: Always use the transducers that were supplied with the instrument.

Transducer set 'A'

Supplied as standard with PUB-A for use on pipes in the range 0.5 to 4.5 inches (13 to 115 mm) OD.

Transducer set 'B'

Supplied as standard with PUB-B for use on pipes in the range 2 to 40 inches (50 to 1000 mm) OD.

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2: Installation

Flow

Valid transducer location

10 x Diameter 20 x Diameter

45°

The PUB equipment expects a uniform flow profile as a
distorted flow will produce unpredictable measurement
errors. Flow profile distortions can result from upstream
disturbances such as bends, tees, valves, pumps and other
similar obstructions. To ensure a uniform profile, the
transducers must be mounted far enough away from any
cause of distortion such that it no longer has an effect.

Uniform Flow Profile Distorted Flow Profile

In many applications an even flow velocity profile over
a full 360° is unattainable due, for example, to the
presence of air turbulence at the top of the flow and
possibly sludge in the bottom of the pipe. Experience
has shown that the most consistently accurate results
are achieved when the transducer holders are
mounted at 45° with respect to the top of the pipe.

Possible
sludge

Air

Flow

T ransducer
Holder

2.1 Transducer Positioning

2: Installation

7

To obtain the most accurate results, the condition of both the liquid and the pipe wall must be suitable to allow the
ultrasound transmission along its predetermined path. It is important also that the liquid flows uniformly within the
length of pipe being monitored and that the flow profile is not distorted by any upstream or downstream
obstructions. This is best achieved by ensuring there is a straight length of pipe upstream of the transducers of at
least 20 times the pipe diameter and 10 times the pipe diameter on the downstream side, as shown in Figure 2.1.
Flow measurements can be made on shorter lengths of straight pipe, down to 10 diameters upstream and 5
diameters downstream, but when the transducers are positioned this close to any obstruction the resulting errors
can be unpredictable.

Key Point: Do not expect to obtain accurate results if the transducers are positioned
close to any obstructions that distort the uniformity of the flow profile.

Figure 2.1 Locating the transducers

2: Installation

A

B

C

D
E

F

G

A: Tensioning thumb-wheel.
B: Tension bar.
C: Separation bar securing

screw.

D: Separation bar.
E: Ruler scale (0).
F: Set separation distance.
G: Securing chain.

2.2 Transducer Attachment

The transducers are fitted to adjustable transducer holders which are secured to the pipe using wrap-around
chains and mechanically connected together by a steel separation bar. The separation bar also acts as a ruler to
allow the distance between the transducers to be accurately set to the value determined by the PUB instrument.

When fitting the transducer holders, it is easiest to assemble them onto the separation bar and adjust to the
required separation distance before attaching them to the pipe.

2.2.1 Preparation

1. Before you attach the transducers you should first ensure that the proposed location satisfies the distance
requirements shown in Figure 2.1, otherwise the resulting accuracy of the flow readings may be affected.

2. Prepare the pipe by degreasing it and removing any loose material or flaking paint in order to obtain the best
possible surface. A smooth contact between pipe surface and the face of the transducers is an important
factor in achieving a good ultrasound signal strength and therefore maximum accuracy.

2.2.2 Attaching the transducer holders

1. Slide the separation bar (D) into the front of the left hand transducer holder, align the front edge of the
transducer holder with ‘0’ on the ruler scale (E) and secure it in place by tightening the thumbscrew (C).

8

2. Slide the other end of the separation bar into the front of the right hand transducer holder, align the front edge
of the transducer holder to the required separation distance (obtained from the PUB instrument) on the ruler
(F), then secure it in place by tightening the thumbscrew.

Figure 2.2 Transducer holder attachment

3. On each transducer holder, attach one end of a securing chain to a hook on the tensioning bar (B), wrap the

A: Transducer cover plate.

B: Transducer locating slot/lug.

C: Transducer cover plate securing screw.

D: Transducer cable connection.

E: Ultrasonic

couplant

application.

G: Chain.

chain (G) around the pipe and then attach it to the hook on the other end of the tensioning bar while keeping
the chain as tight as possible.

4. Rotate the complete transducer holder assembly so that it is approximately 45° with respect to the top of the
pipe. Then tighten the chain by turning the tensioning thumb-wheel (A) on each guide block until the
assembly is securely attached to the pipe.

Note: If you are unable to get sufficient tension on the chain to hold the assembly in place, fully slacken the
tensioning thumb-wheel and shorten the effective length of the chain wrapped around the pipe by connecting
the tensioning bar to the next link in the chain, then re-tension.

2.2.3 Fitting the transducers

2: Installation

Figure 2.3 Fitting the transducers

1. Slide the transducer cover plate (A) fully towards the outside of the holder assembly to allow sufficient access
to fit the transducer.

2. Clean the face of the transducer, removing all traces of dirt and grease.

3. Apply a

4. Fit the transducer into the holder – ensuring the lugs on the sides of the transducer are correctly located into
the slots on the sides of the guide block (B).

5. Slide the transducer cover plate (A) over the top of the transducer and tighten the thumbscrew (C) finger tight
to secure the transducer in place. When securing the cover plate take care to leave sufficient room around
the transducer connector (D) to connect the cable.

6. Repeat the above steps for the second transducer.

7. Connect the transducers to the PUB instrument using the coaxial cables provided. The RED cable must be
connected to the upstream transducer and the BLUE cable to the downstream transducer. If you observe
negative flow, swap the red and blue cables at the sensor end.

9

1

/10 inch bead of ultrasonic couplant along the center length of the transducer (E).

3: Operating Procedures

QUICK START VIEW EDIT SITE DATA

Enter data

Attach sensors

FLOW READING

Choose site / check/edit data

Attach sensors

FLOW READING

Set up a named site

At a one-off location

(Paragraph 3.2)

At a frequent location

(Paragraph 3.3)

Manage site details

(Paragraph 3.4)

Carry out any necessary calibration

(Paragraph 3.5)

How to adjust the Zero Flow Offset – Paragraph 3.5.2
How to adjust the Calibration Factor – Paragraph 3.5.3
How to adjust the Roughness Factor – Paragraph 3.5.4
How to adjust the Damping Factor – Paragraph 3.5.5

Set-up a monitoring application

(Paragraph 3.6)

How to measure totalized flows – Paragraph 3.6.1

Configure the interfaces

(Paragraph 3.7)

Battery charging, Set date/time, Language, Backlight

Initial instrument setup

(Paragraph 3.1)

Connect and take basic flow readings

Rename a site

4-20mA ON/OFF – page 24
4-20mA Calibration – page 25
Pulse ON/OFF – page26
Pulse calibration – page 27
Pulse frequency mode – page 27
Pulse frequency calibration – page 28

3: Operating Procedures

10