Precision Acoustics UMS Instruction sheet

PRODUCT INSTRUCTIONS
UMS Overview
Precision Acoustics Ltd is pleased to be able to offer our Ultrasonic Measurement System
(UMS).
UMS is a custom built test tank system for making a variety of ultrasound measurements. This
document describes the configuration and connection of the hardware part of the system.

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CONTENTS
Introduction...................................................................................................................................................3
Principal system components........................................................................................................................3
Table of Components.................................................................................................................................3
Measurement Tank....................................................................................................................................3
Motion Control Actuators and Frame .......................................................................................................4
Description............................................................................................................................................................4
Axis labelling convention......................................................................................................................................4
Two-Rotational Axes Gimbal Mount .........................................................................................................4
Axis Labelling Convention.....................................................................................................................................4
Stepper Motor Drive Control Unit........................................................................................................................4
Emergency Stop System ............................................................................................................................5
Filling The Tank.....................................................................................................................................................5
Refilling The Tank..................................................................................................................................................5
Digital Storage Oscilloscope ......................................................................................................................6
Host PC.......................................................................................................................................................6
UMS Software............................................................................................................................................6
System setup..................................................................................................................................................6
Parts List.........................................................................................................................................................7
VERSION HISTORY
Version
Date
Description
3
11/06/2020
Updated to new style and minor changes

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INTRODUCTION
UMS is a custom-built test tank system for making a variety of ultrasound measurements. This document
describes the configuration and connection of the hardware part of the system. For information relating
to the use of the control and post processing software, please refer to the appropriate user manual.
Items relevant to the safe operation of the UMS system will be highlighted as per this entry.
PRINCIPAL SYSTEM COMPONENTS
IMPORTANT NOTE:
For user convenience, the components of the UMS are fully assembled and wired together. Unpacking
the shipment crate is therefore likely to require several people.
Table of Components
Description
Quantity
Water Tank
1
Fully assembled frame with stepper motor control and wired motion actuator
system
1
Stepper Motor Drive Control Unit Door Handle
1
Oscilloscope
1
Host PC
1
PC Monitor
1
UMS Software V3.0
1
Hydrophone rod holder
1
2-axis of rotation Transducer Mount
1
Water Treatment System complete with deionisation cartridge and hoses
1
Thermocouple based temperature monitoring System
1
Measurement Tank
The ultrasonic measurement tank is constructed from 15mm thick Perspex (Plexiglas) with fully bonded
seams and joints
The measurement tank should be positioned within the test tank frame. It is particularly important to
ensure the surface remains flat once the tank is full of water. Insufficiently reinforced work surfaces can
bend or bow under the weight of a full water tank, which results in the tank being unevenly supported.
This is likely to cause additional stressing of the joints of the tank and could results in the tank fracturing.
Another possible cause of fracture can occur if the surface is not flat, or if a small object (e.g. piece of grit),
is trapped between the bottom of the tank and the work surface.

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Motion Control Actuators and Frame
Description
This component is principally concerned with the movement of the hydrophone within the measurement
tank. There are four linear motion stages (3 powered, 1 slave). Each linear actuator is based upon a 2mm
pitch ball screw that is driven by a stepping motor. Closed-loop control is provided by a load mounted
linear magnetic encoder giving a read out positional resolution of 1 m. With all stepper motor driven
systems there exists the possibility that the number of steps completed by the actuator will not be the
same as the number steps requested by the drive controller. This generally results in the actuator not
moving as far as expected. When the encoders are activated their output is fed back to the drive
controller. If there is a difference between the distance moved by the actuator, and that initially
requested, the drive controller calculates the necessary correction and automatically moves the drive as
appropriate. The encoder deadband is set by default to 6 µm giving positional accuracy of ±6 µm. As a
safety precaution all drives have two limit switches that can be used to prevent the actuator from moving
beyond particular user-definable positions. These can be used to prevent collision between the
hydrophone and static objects, such as the walls of the tank, or into obstacles placed within the tank.
Axis labelling convention
To prevent confusion when identifying axes, the following conventions are adopted:
•The Z-axis (in keeping with standard acoustics nomenclature) is the acoustic axis of the
transducer. For vertically mounted systems (transducer firing top down or bottom up) the
Z-axis will be the vertical axis. For horizontally mounted systems, the Z-axis is the longest
horizontal axis of the tanks
•The X-axis is always defined as the axis which crosses the tank
•The Y-axis is thus defined as the longitudinal axis of the tank (for vertically mounted
systems) or the vertical axis (for horizontally mounted systems).
All axes adopt the convention that the positive direction is away from the actuator motor.
Two-Rotational Axes Gimbal Mount
Optional rotational mounts are available. See the documentation supplied with your mounts for more
information.
Axis Labelling Convention
Once X and Y axis have been identified the two rotational axes on the gimbal are simply identified as
rotation about the X-axis (Abt_X) and about the Y-axis (Abt_Y).
Stepper Motor Drive Control Unit
This unit contains the stepper motor drive controllers and their associated power supplies. It also contains
the temperature monitoring system. Each motion actuator has its own dedicated drive controller within
the cabinet. These controllers deal with all aspects of motion control. In addition to supplying power to
the stepper motors, they also implement the actions required by the limit or emergency stop switches, as
well as administering position maintenance instructions when the system is used with drive encoders. The
drive control unit is mains powered, and is fitted with a door cut-out switch that interrupts the mains

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power whenever the cabinet door is opened. Opening the door will immediately trigger the switch and
cut power to the stepper motors on the motion actuators (note the drive controllers remain active via a
24 V dc “logic” supply). This is clearly undesirable if the UMS is in the middle of a measurement, and the
cabinet door should therefore be kept shut at all times. A black plastic handle for the cabinet is included
with the UMS. This handle can be removed from the unit to prevent unauthorised access and should be
stored safely when not in use. The drive control unit should ALWAYS be connected to the mains electricity
supply by means of a Residual Current Circuit Breaker (RCCB). The RCCB should also be tested every time
that the system is used.
This unit is mains powered and whilst the enclosure is splash proof, it is not fully waterproof. Therefore this unit
should NOT be placed anywhere near direct sources of water
Emergency Stop System
The UMS test tank system is equipped with an emergency stop (E-STOP) switch. The switch is connected
to the control box by a cable sufficiently long to be positioned close to the user at all times.
When pressed the switch latches in the “ESTOP Active” position. Once safe to do so, the ESTOP can be
released by twisting the red pushbutton in the direction indicated on it.
The consequences of pressing the ESTOP are as follows:
1. Power is immediately cut to the stepper motors on the linear axes and if applicable the
stepper motor controlled rotary table.
a. Logic power supply to the stepper controllers and encoders is maintained allowing the
system to maintain a record of its position.
2. All power is cut to the optional Gimbal mount (assuming the gimbal mount wiring is integral
to the system, where a gimbal mount has been supplied as an add-on, this may not apply).
a. Note: Since the motors used in the current gimbal mount are servos, they can be
“backdriven” when power is removed. Therefore great care should be taken to avoid
mounting heavy items on the gimbal above its pivot point (as this arrangement is inherently
unstable and removing power could cause the load to flip and potentially cause damage to
the system).
3. The software process which was running will detect the ESTOP activation and “pause” its
execution. A dialogue is displayed on the screen indicating that the ESTOP has been
activated. The user can then clear this dialogue by selecting the appropriate option once
the ESTOP has been released.
Filling The Tank
The tank should be filled with deionisation water.
Refilling The Tank
The test tank should be refilled when necessary. How regularly the water in the test tank requires
changing will be largely dependent on the size of the tank and the environment in which the test tank is
situated. The user will be best placed to judge if the water has become discoloured over time, or has “re-

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ionised”. For precise control of the water quality it is recommended that the user procures both a
dissolved air (and at least dissolved oxygen) and conductivity meter and closely monitors these water
properties. The conductivity of the degassed water should be less than 4 uS/cm (1) and the dissolved
oxygen content between 5-8 ppm or <4 ppm for high powers (>10W) (2).
At Precision Acoustics the test tank water is changed approximately every 3 to 6 months.
(1) IEC 62127 part 1
(2) NEMA UD-2
Digital Storage Oscilloscope
The UMS is designed to operate with digital storage oscilloscopes from the Keysight DSOX range. These
high specification digital storage oscilloscopes (DSO) are used for all data acquisition and also handle all
the data transfer back to the host PC by means of onboard Ethernet or GPIB communication. Support for
other oscilloscopes may be available, for further information please contact us with your specific model.
Host PC
NOTE: the host PC login password is set to ACOUSTICS or Measurement.
This PC runs the UMS Software that is at the heart of the UMS. If you have purchased a PC for this purpose
from PAL, all the necessary software will have been pre-installed. If however you are using your own PC
then further set up will be required. Once assembled, the PC will use a USB port to interface with the
Stepper Motor Drive Control Unit (section 2.4). The PC communicates with the DSO via an Ethernet (RJ45)
connector. All data acquired by the DSO is also passed back to PC for storage and subsequent post
processing.
UMS Software
The ultrasonic measurement system is controlled from the Host PC by means of dedicated LabVIEW
based software. UMS software application controls all aspects of the operation of the system including:
•Initialisation of communication interfaces
•Motion of the stepper motor actuators
•Waveform acquisition by the oscilloscope and subsequent transfer of data to the host PC
•Acquisition and storage of temperature data
•Archival and post-processing of acquired data
SYSTEM SETUP
A schematic overview of the installation of the UMS system is shown in the figure below.

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PARTS LIST
Below are the main test tank parts:
Description
Quantity
Manufacturer
Part number
Supplier
Anodised aluminium gantry
framework and fixings
1
Minitec
n/a
LG
Motion/Minitec
Water tank
1
Angloplas
n/a
Precision
Acoustics Ltd
Linear actuators
4
Velmex
BiSlide
LG Motion
Stepper motors on linear
axes
3
Oriental Motor
PK266 and PK296
LG Motion
Stepper motor controllers
3
Parker
ViX250/500IM
LG Motion
Stepper motor power
supply
1
Parker
XL PSU
LG Motion
Linear magnetic encoder
scales
3
Renishaw
LM10
Precision
Acoustics
Host PC
Stepper Motor
Drive Control
Unit
UMS
Software
Oscilloscope
Motion
Control
Actuators and
Frame
Function
Generator
(Not Supplied)
Trigger
Hydrophone
in
Hydrophone
Mount
Measureme
nt Tank
Ultrasonic
Source in
Transducer
Mount
Motion
Control
Acquisitio
n Control
Drive
Signal
Hydrophon
e Signal
Motion
Control
Z Axis
X Axis
Y Axis

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Linear magnetic encoder
read head
3
Renishaw
LM10
Precision
Acoustics
Reference markers for
Linear magnetic encoder
scales
3
Renishaw
LM10
Precision
Acoustics