Dwyer Instruments UFM2 User manual

Issue 1.1
UFM2/UBT
UFM2: Clamp-on Ultrasonic Flow Meter
UBT: Clamp-on Ultrasonic Heat Meter
User Manual
UBT shown
DWYER INSTRUMENTS, INC.
102 INDIANA HWY 212
MICHIGAN CITY
INDIANA 46360
USA
Phone: [phone]
Fax: [phone]
Web: www.dwyer-inst.com
Email: [e-mail]

UFM2/UBT User Manual
Issue 1.1b July 20 Page i
CONTENTS
1INTRODUCTION....................................................................................... 1
1.1 General Description............................................................................................................1
1.2 How Does It Work?.............................................................................................................2
1.3 Package Contents ..............................................................................................................3
1.4 Display................................................................................................................................4
1.5 Quick Start Procedure ........................................................................................................5
2INSTALLATION......................................................................................... 6
2.1 Identify Suitable Location....................................................................................................6
2.1.1 Additional Considerations for Locating UBT.................................................................6
2.1.2 Clean the Pipe’s Flow Sensor Contact Area ................................................................7
2.2 Connect Power and Signal Cables .....................................................................................7
2.2.1 Power Supply ..............................................................................................................7
2.2.2 Pulse Output Connection.............................................................................................8
2.2.3 Current Output (UFM2 only) ........................................................................................8
2.2.4 Modbus Connections (if fitted) .....................................................................................8
2.2.5 Temperature Sensor Probes (UBT only)....................................................................10
2.3 Switch On.........................................................................................................................11
2.3.1 UFM2 ........................................................................................................................11
2.3.2 UBT...........................................................................................................................12
2.4 Adjust Flow Sensor Separation.........................................................................................13
2.5 Apply Gel Pads.................................................................................................................13
2.6 Clamp Sensor Assembly to Pipe.......................................................................................14
2.6.1 Pipe Adaptors............................................................................................................14
2.6.2 Attaching to Pipe .......................................................................................................15
2.7 Remove Sensor-Holding Screws......................................................................................16
2.8 Connect Electronics Module.............................................................................................16
2.9 Attach the Temperature Sensors (UBT Only)....................................................................17
2.10 Normal Operation .............................................................................................................18
2.10.1 UFM2 ........................................................................................................................18
2.10.2 UBT...........................................................................................................................18
2.10.3 Troubleshooting the Flow Reading ............................................................................19
2.11 Clip Electronics Module to Sensor Assembly....................................................................19
3MENUS.................................................................................................... 20
3.1 Accessing the Menus........................................................................................................20
3.2 Setup Menu......................................................................................................................21
3.3 Modbus Menu...................................................................................................................22

UFM2/UBT User Manual
Page ii Issue 1.1b July 20
3.4 Current Output Menu (UFM2 only)....................................................................................23
3.5 Pulse Output Menu...........................................................................................................24
3.6 Calibration Menu ..............................................................................................................25
3.7 Volume Totals Menu.........................................................................................................26
3.8 Diagnostics Menu.............................................................................................................27
4OUTPUTS................................................................................................ 28
4.1 Pulse Output.....................................................................................................................28
4.1.1 Volumetric Pulse........................................................................................................28
4.1.2 Frequency Mode........................................................................................................29
4.1.3 Energy Pulse (UBT only) ...........................................................................................29
4.1.4 Flow Alarm - Low Flow ..............................................................................................29
4.1.5 Flow Alarm –Signal Loss ..........................................................................................29
4.24-20 mA Current Output (UFM2 only, if fitted)...................................................................29
4.3 Modbus (if fitted)...............................................................................................................30
5RELOCATING THE UNIT......................................................................... 33
6APPENDIX .............................................................................................. 34
6.1 Specification.....................................................................................................................34
6.2 Default values...................................................................................................................36
6.3 Limitations with Water-Glycol Mixtures .............................................................................36
6.4 Positioning........................................................................................................................36
6.5 Error and Warning Messages ...........................................................................................38
6.5.1 Error Messages.........................................................................................................38
6.5.2 Example Error Messages...........................................................................................38
6.5.3 Modbus Error Messages (if Modbus fitted) ................................................................39
6.5.4 Flow Errors................................................................................................................39
6.5.5 Flow Warnings...........................................................................................................39
6.5.6 Data Entry Errors.......................................................................................................40

UFM2/UBT User Manual
Issue 1.1b July 20 Page 1
1INTRODUCTION
1.1 General Description
This manual describes the installation and use of the UFM2 flow meter and UBT energy meter:
•UFM2 is an ultrasonic clamp-on flow meter for measuring flow rate and total flow with a volume
pulse output and optional Modbus or 4-20 mA flow proportional output. It can be used as a
standalone meter or as part of an integral management system.
•UBT is an ultrasonic clamp-on thermal, heat/energy meter. It uses ultrasound to measure flow
rate and is also equipped with PT100 temperature sensors to measure flow and return
temperatures. The energy meter displays energy rate and totalised energy with pulse output
and communication options, so it can be used as a standalone meter or as an integral part of
Automatic Monitoring & Targeting (aM&T) or a Building Energy Management System (BEMS).
The electronics and sensor housings form an integral unit which attaches to the pipe using the
supplied hose clips. Power to the unit is provided by an external 12-24 VDC / 24 VAC power supply
(7 W / 7 VA minimum). The unit operates on steel, stainless steel, copper and plastic pipes with
internal diameter in the range 0.8” (20 mm) to 6.5” (165 mm) depending on the product purchased.
The models can also be supplied with Modbus digital communication options.
Typical applications:
UFM2
UBT
Hot water metering and flow measurement
Hot water metering and flow measurement
Flow measurement for heat metering
Flow measurement for Energy Metering
Chilled water metering and flow measurement
Chilled water metering and flow measurement
Potable water metering and flow measurement
Process water metering and flow measurement
Ultra-pure water metering and flow
measurement.
NOTE:
The UBT default configuration is:
•Instrument Type: Heating
•Installation Side: Return
•Fluid: Water
Return refers to the location of the flow measurement relative to flow circuit.

UFM2/UBT User Manual
Page 2 Issue 1.1b July 20
1.2 How Does It Work?
The UFM2 and UBT meters use a cross correlation transit time algorithm to provide accurate flow
measurements.
An ultrasonic beam of a given frequency is generated by applying a repetitive voltage pulse to the
transducer crystals. This transmission goes first from the downstream (blue) transducer to the
upstream transducer (red) as shown in the upper half of Figure 1. The transmission is then made in
the reverse direction, being sent from the upstream transducer (red) to the downstream transducer
(blue) as shown in the lower half of Figure 1. The speed at which the ultrasound is transmitted
through the liquid is accelerated slightly by the velocity of the liquid through the pipe. The
subsequent time difference T1 –T2 is directly proportional to the liquid flow velocity.
With the UBT, two temperature sensors measure the difference in temperature between the supply
and return of the flow system being monitored. The temperature difference, in combination with the
volume of water that has flowed through the system, is then used to calculate the energy transferred
to or from the water.
Figure 1 Principle of Transit-Time operation

UFM2/UBT User Manual
Issue 1.1b July 20 Page 3
1.3 Package Contents
The unit consists of two parts:
1. Sensor Assembly
Incorporating guide rails and two transducers for flow measurement.
2. Electronics Module
Consisting of the keypad and display, power, signal and Modbus connections. The Electronics
Module clips onto the Sensor Assembly.
In addition, the kit contains:
3. Adhesive gel pads (4)
4. 2-part adaptors for fixing sensor assembly to pipes with an OD less than 2 ½" (75 mm) (2).
5. UBT only: Non-releasable stainless cable ties for temperature sensors (2)
6. Quick release clamps for use with pipes with an OD of ¾ - 2 ½" (25-75 mm) (2)
7. Quick release clamps for use with pipes with an OD of 2 –5" (63-140 mm) (2)
8. UBT only: PT100 temperature sensors with cable (9.8' (3 m)) (2)
9. Modbus cable (optional)
The kit also contains a copy of this manual.
Figure 2 Package Contents
1
2
9
3
4
5
6
7
8

UFM2/UBT User Manual
Page 4 Issue 1.1b July 20
1.4 Display
The meter display comprises:
•One 2-line x 16 character LCD with backlight
•Four tactile key switches
•Two LEDs
Figure 3 Display (UBT model shown)
BTU (UBT)
Energy pulse signal
4-20 mA (UFM2)
4-20 mA signal.
Pulse
Illuminated when the
Pulse, Frequency or
Alarm functions are
enabled.
Select
Selection key.
Choose between
options on the
display.
Decrease/Down
Decrement the
value of each
digit in numeric
entry fields/move
menu down.
Increase/Up
Increment the
value of each
digit in numeric
entry
fields/move
menu up.
Enter
Enter displayed
selection/
terminate the
data entry.
Select menu or
exit to Flow
Reading screen.
Flow
Measured flow.
Signal strength
For accurate
results, must be
over 40%.
Flow Units
Units applicable to
measured flow.
Flow Direction
* Indicates positive
flow
! Indicates
reversed flow.

UFM2/UBT User Manual
Issue 1.1b July 20 Page 5
1.5 Quick Start Procedure
The following procedure summarises the steps required to set up the meter. Please refer to the
referenced sections for full details.
1. Identify a suitable location for the meter on a straight length of pipe clear of bends and valves or
similar obstructions (See pages 6 and 36).
2. Electronics Module:
a. Connect to a 12 –24 VDC or 24 VAC power supply (7 W / 7 V minimum per
instrument) using the Blue and Brown wires. (See page 7).
b. Switch on and program to determine the correct separation code. (see page 11).
3. Sensor Assembly:
a. Loosen but do not remove the two sensor-holding screws to lower the flow sensors
so they can slide along the Sensor Assembly’s internal guide rail (see page 13).
b. Set the flow sensors to the correct separation (see page 13).
c. Tighten the sensor-holding screws.
d. Apply the gel pads to the sensors (see page 13).
e. Mount the Sensor Assembly onto the pipe using the supplied hose clips
(see page 15).
If the pipe has an OD less than 2 ½" (75 mm), use the adaptors provided (see page
14).
f. Remove the sensor-holding screws (see page 16).
4. Connect the two wires from the Sensor Assembly to the Electronics Module (see page 16).
DO NOT CLIP THE ELECTRONICS MODULE ONTO THE SENSOR ASSEMBLY AT
THIS STAGE. THE ELECTRONICS MODULE CAN BE FULLY CLIPPED DOWN LATER
ONCE ALL MEASUREMENTS HAVE BEEN CHECKED.
5. UBT only: Plug in the temperature sensors to the Electronics Module (see page 17) and attach
the PT100 sensors to the flow and return pipes (see Section 2.1.1, page 6).
6. Check that flow readings can be obtained (see page 18).
7. Clip the Electronics Module to the Sensor Assembly and tighten the side screw to complete
assembly (see page 19).
To use the Pulse Output features, see page 28.
To use the 4-20 mA Output, see page 29 (UFM2 only).
To use the Modbus interface, see page 30. The address, data rate, and configuration of the
instrument must be set using the Modbus Menu (see page 22). The default address is 1, the default
data rate is 38400 baud, and the default Comms configuration is 8-None-2.

UFM2/UBT User Manual
Page 6 Issue 1.1b July 20
2INSTALLATION
2.1 Identify Suitable Location
We recommend a location where there is a straight length of pipe with no bends, constrictions or
obstructions within at least 10 times the pipe diameter upstream, and 5 times the pipe diameter
downstream.
Figure 4 Identifying a suitable location
IMPORTANT: DO NOT EXPECT TO OBTAIN ACCURATE RESULTS IF THE UNIT IS
POSITIONED CLOSE TO ANY OBSTRUCTION THAT DISTORTS THE UNIFORMITY OF
THE FLUID FLOW PROFILE (SEE PAGE 36). DWYER INSTRUMENTS INC. ACCEPTS
NO RESPONSIBILITY OR LIABILITY IF PRODUCT HAS NOT BEEN INSTALLED IN
ACCORDANCE WITH THESE INSTRUCTIONS.
2.1.1 Additional Considerations for Locating UBT
For optimum reliability on boiler applications, the flow measurement needs to be made on the cold
side of the system. For optimum reliability in chiller applications, the flow measurement needs to be
made on the warmer side of the system.
Figure 5 Typical setup of UBT for boiler applications
UPSTREAM
10 x pipe
diameter
DOWNSTREAM
5 x pipe
diameter
UFM2/UBT
fluid flow

UFM2/UBT User Manual
Issue 1.1b July 20 Page 7
2.1.2 Clean the Pipe’s Flow Sensor Contact Area
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 sensors is an
important factor in achieving a good ultrasound signal strength and therefore maximum accuracy.
UBT: The area of pipe where the temperature sensors are to be attached must be free of grease
and any insulating material. It is recommended that any coating on the pipe is removed so that the
sensor has the best possible thermal contact with the pipe.
2.2 Connect Power and Signal Cables
This section explains how to connect power and signal cables to the Electronics Module.
2.2.1 Power Supply
The meter will operate within the voltage range 12 - 24V DC/ 24V AC. The supply must have a
minimum rating of 7W/7VA per instrument. Connect the external power supply to the Brown and
Blue wires of the six-core cable.
EXTERNAL POWER SUPPLY MUST BE CLASS 2 RATED.
IMPORTANT: IT IS THE RESPONSIBILITY OF THE INSTALLER TO CONFORM TO THE
REGIONAL VOLTAGE SAFETY DIRECTIVES WHEN CONNECTING THE METER TO A
POWER SUPPLY USING A MAINS-RATED TRANSFORMER.
The interface cable supplied is a 6-core cable for power, pulse output and 4-20 mA (if fitted)
connections.
Figure 6 6-core main interface cable
The un-insulated wire is the connection to the screen of the cable and should be earthed for full
immunity to electrical noise.

UFM2/UBT User Manual
Page 8 Issue 1.1b July 20
2.2.2 Pulse Output Connection
The isolated pulse output is provided by a SPNO/SPNC MOSFET relay which has a maximum load
current of 500 mA and maximum load voltage of 24 VAC/VDC.
THIS OUTPUT IS SUITABLE FOR SELV CIRCUITS ONLY.
The pulse output is available at the White and Green wires. Electrically this is a Volt, or potential
free contact and, when selected as a low flow alarm, is configurable NO/NC.
2.2.3 Current Output (UFM2 only, if fitted)
The isolated 4-20 mA is a current source and can drive into a maximum load of 620 Ω.
The 4-20 mA current output is available at the Red and Black wires. The polarities are shown in
Figure 6. The alarm current due to a flow outside the range specified or due to a loss of signal is set
at 3.5mA.
THIS OUTPUT IS SUITABLE FOR SELV CIRCUITS ONLY.
2.2.4 Modbus Connections (if fitted)
A separate 4 core plug-in cable is provided for the Modbus connections.
This plugs into the Electronics Module near the power cable entry.
PIN
FUNCTION
COLOR
1
MODBUS -ve
BLACK & BROWN
2
OPTIONAL GND
SCREEN
3
MODBUS +ve
BOTH WHITES
4
-
-
Figure 7 Modbus Connector Cable Part - Binder 99-9210-00-04 (Front View)
Figure 8 Modbus cable wiring

UFM2/UBT User Manual
Issue 1.1b July 20 Page 9
NOTE: ENSURE THE WHITE WIRES ARE CORRECTLY ASSOCIATED WITH THE
BLACK & BROWN WIRES. THE BLACK/WHITE TWISTED PAIR IS FITTED WITH A
BLACK SLEEVE TO DISTINGUISH BETWEEN THE BLACK/WHITE AND
BROWN/WHITE PAIRS.
For reliable operation of a Modbus network the cable type and installation must comply with
requirements in the Modbus specification document “MODBUS over Serial Line Specification &
Implementation guide V1.0”.
THIS OUTPUT IS SUITABLE FOR SELV CIRCUITS ONLY.
For full immunity to electrical interference the screen of the power/pulse output cable and Modbus
cable should be connected to Earth.
For full immunity to electrical interference the screen of the power/pulse output cable and Modbus
cable should be connected to Earth.
Figure 9 Example recommended Modbus wiring diagram
+V (+5V or +12V)
RS485+
RS485-
GND (0V)
120Ω
270Ω
270Ω for +5V, 1KΩ for +12V
Screen
UFM2/UBT
Brown
White
Black
UFM2/UBT
Spur Length
Cables of any specified length can be supplied to order.
Isolated
RS-485
+
-
Screen
Isolated
RS-485
0V
+
-
Screen
0V
White
Screen
Isolated
RS-485
0V
+
-
UFM2/UBT
Optional Ground
White
Black
White
White
Black
White
Brown
Brown
Spur Length
120Ω
Modbus Master

UFM2/UBT User Manual
Page 10 Issue 1.1b July 20
2.2.5 Temperature Sensor Probes (UBT only)
Two separate 4-core plug-in cables are provided for the Temperature Sensor Probes connections.
These plug into the right-hand side of the Electronics Module.
Figure 10 UBT Temperature Probe Wiring
UBT
COLD
HOT
White
White
Red
Red
White
White
Red
Red
4
3
1
2
Solder pin side

UFM2/UBT User Manual
Issue 1.1b July 20 Page 11
2.3 Switch On
The initial screen sequence is different for the UFM2 and UBT models.
2.3.1 UFM2
Switch on the power to the Electronics Module. A start-up screen is displayed for 5 seconds
followed by hardware and software version information.
You are then prompted to enter the internal diameter of
the pipe:
Use the , and keys to change the value.
Press to confirm the value.
Select the pipe material by using the and
keys to scroll through the list.
Press to confirm the material.
Select the fluid using the key.
Press to confirm the fluid name.
If the fluid temperature is in the range 36°F to 104°F
select “COLD”. If the fluid temperature is in the range
104°F to 185°F select “HOT”.
The unit now shows the correct flow sensor separation
(in this case, “B2”) for the chosen values of pipe ID,
pipe material and fluid.
Make a note of the separation code.
All subsequent start-ups will use the same configuration.
Continue with the installation of the Sensor Assembly (see page 13).
Select Material:
Steel
Instrument Fluid
Glycol | Water
Set Temperature:
HOT | COLD
Set Separation:
B 2
Enter Pipe ID :
1.969 inches

UFM2/UBT User Manual
Page 12 Issue 1.1b July 20
2.3.2 UBT
Switch on the power to the Electronics Module. A start-up screen is displayed for 5 seconds
followed by hardware and software version information.
You are then prompted to enter the internal diameter of
the pipe:
Use the , and keys to change the value.
Press to confirm the value.
Select the pipe material by using the and
keys to scroll through the list.
Press to confirm the material.
Select the instrument setting using .
The unit is preconfigured for Heating applications.
Press to confirm the setting.
Select which side the unit is installed on using .
The unit is preconfigured for Return.
Press to confirm the setting.
Select the fluid using .
Press to confirm the fluid name.
If the fluid temperature is in the range 36°F to 104°F
select “COLD”. If the fluid temperature is in the range
104°F to 185°F select “HOT”.
The unit now shows the correct flow sensor separation
(in this case, “B-2”) for the chosen values of pipe ID,
pipe material and fluid.
Make a note of the separation code.
All subsequent start-ups will use the same configuration.
Continue with the installation of the Sensor Assembly (see page 13).
Enter Pipe ID :
1.969 inches
Pipe Material:
PLASTIC
Instrument Type:
Heating|Chiller
Instrument Side:
Return|Flow
Instrument Fluid
Glycol|Water
Set Temperature:
HOT | COLD
Set Separation:
B-2

UFM2/UBT User Manual
Issue 1.1b July 20 Page 13
2.4 Adjust Flow Sensor Separation
Using the separation code displayed by the Electronics Module (see page 10), take the Sensor
Assembly and adjust the flow sensor separation accordingly:
Figure 11 Loosen the flow sensor-holding screws (left); slide to correct position (right)
1. Undo the screws 2-3 turns, sufficiently to loosen the flow sensors and allow sideways
movement. DO NOT fully unfasten or remove the screws at this stage.
2. Slide the flow sensors to the positions indicated on the display (e.g. “D5”).
3. With the flow sensors in the correct positions, tighten the sensor-holding screws so that the
sensors are secure.
2.5 Apply Gel Pads
1. Apply a gel pad centrally onto the bases of each of the two flow sensors.
2. Remove the covers from the gel pads.
3. Ensure there are no air bubbles between each pad and sensor base.
Figure 12 Applying the gel pads

UFM2/UBT User Manual
Page 14 Issue 1.1b July 20
2.6 Clamp Sensor Assembly to Pipe
The next step involves clamping the Sensor Assembly onto the pipe. Ensure that you have selected
a suitable location (see pages 6 and 36) and that the pipe is clean (see page 7). If you are installing
the unit on a pipe with an outside diameter less than 2.36 inches (60 mm) use one or more of the
adaptors supplied with the unit.
2.6.1 Pipe Adaptors
The diagrams below show how the adaptors are fitted. The top ‘V’ shaped adaptor clips onto the
ends of the Sensor Assembly and this should be used with all pipes with an outside diameter less
than 2.36 inches (60 mm).
Additionally, for pipes with an outside diameter less than 1.57 inches (40 mm), a second adaptor
should also be used. This fits underneath the pipe as shown below.
IMPORTANT: DO NOT USE THESE ADAPTORS IF THE PIPE HAS AN OUTSIDE
DIAMETER GREATER THAN 2.36 INCHES (60 MM).
Figure 13 Pipe adaptors in position: 1 ½ - 2 ½ " (40-60 mm) OD (left),
less than 1 ¼" (40 mm) OD (right)

UFM2/UBT User Manual
Issue 1.1b July 20 Page 15
2.6.2 Attaching to Pipe
1. For pipes with an outside diameter less than 2.36 inches (60 mm), attach the black clips to the
bottom of the Sensor Assembly as shown below.
Figure 14 Attaching pipe adaptor
2. Place the Sensor Assembly on pipe.
3. For pipes with an outside diameter less than 1.57 inches (40 mm), position the curved adaptor
under the pipe.
Figure 15 Clamping pipe adaptor to pipe with OD less than 1 ¼" (40 mm)
4. Using the hose clips provided, clamp the Sensor Assembly (and adaptors, if used) to the pipe at
an angle of 45° to the top of the pipe. Experience has shown that the most consistently
accurate results are achieved when the unit is mounted at this angle (see page 36). This
minimises the effect of any flow turbulence resulting from entrained air along the top of the pipe
and sludge at the bottom.
Figure 16 Sensor Assembly clamped at 45°
45°
Air
Sludge

UFM2/UBT User Manual
Page 16 Issue 1.1b July 20
2.7 Remove Sensor-Holding Screws
Release and remove the sensor-holding screws. The flow sensors are spring-loaded to ensure good
contact with the pipe surface.
NOTE: THE SENSOR-HOLDING SCREWS AND WASHERS SHOULD BE KEPT IN A
SAFE PLACE IN CASE IT IS NECESSARY TO RELOCATE THE UNIT (SEE PAGE 28).
Figure 17 Removing sensor-holding screws
2.8 Connect Electronics Module
1. Ensure that the power is switched off.
2. Connect the Electronics Module (wired as described on page 7). The two leads can be
connected either way round.
IMPORTANT: DO NOT CLIP THE ELECTRONICS MODULE ONTO THE SENSOR
ASSEMBLY UNTIL YOU HAVE CHECKED OPERATION.