New-Flow Pico RMU User manual

Newflow
Pico RMU
Incorporating
TorqueWrench
User
Manual

Contact:
Newflow Ltd
George House
Derwent Road
Malton, North Yorkshire
YO1 6YB, UK
Tel: [phone]
Email: [email protected]
Document Information
Document Name Pico RMU User Manual
Document Identifier PicoRMU-UM
Rev Date Changes Prepared Chec ed Authorized
0 1 Jun 2022 Initial Version MOB DGS MOB
1 1 Jul 2022 Added Isolated RS422 wiring MOB DGS MOB
2 4 Aug 2022 Added additional loop drawings and Modbus map MOB GPL MOB
3 3 Oct 2022 Added Potted unit information ARN352 MOB DGS MOB
4 5 May 2023 Added Pressure Correction for Density meters
Firmware Version: 1v00r0
MOB DGS MOB
Page 2 of 31 Pico RMU User Manual PicoRMU-UM-R4
NÅNO (with Angstrom symbol) and Visual C||Cure are registered trademarks of Newflow Ltd.
All trademarks are a knowledged as the property of their respe tive owners.
TESTit & PROVEit are trademarks of Quorum Business Solutions, In . (Flow-Cal, In ).
This do ument, submitted in onfiden e, ontains proprietary information and shall not be reprodu ed or
transferred to others without prior written permission of Newflow Ltd.
This do ument shall not form part of any ontra t. Spe ifi ations are subje t to hange without noti e and
Newflow Ltd a epts no liability of any kind for errors or omissions.
Full ontra tual terms are available on the website at www.newflow. o.uk/pdf/tand .pdf

PicoRMU-UM-R4 Pico RMU User Manual Page 3 of 31

Table of Contents
1 Introduction..................................................................................................................................... 5
2 Pico RMU I/O...................................................................................................................................6
2.1 Field I/O..................................................................................................................................................... 6
2.2 Communica ions........................................................................................................................................ 7
2.3 Inpu Power................................................................................................................................................ 7
2.4 Digi al Inpu s.............................................................................................................................................. 7
2.4.1 Digi al Inpu Circui Overview.........................................................................................................................................................7
2.4.2 Digi al Inpu Func ional Represen a ion.........................................................................................................................................7
2.4.3 Digi al Inpu Field Wiring Example..................................................................................................................................................8
2.5 Digi al Ou pu s........................................................................................................................................... 9
2.5.1 Digi al Ou pu Circui Overview.......................................................................................................................................................9
2.5.2 Digi al Ou pu Func ional Represen a ion.......................................................................................................................................9
2.5.3 Digi al Ou pu Field Wiring Example.............................................................................................................................................10
2.6 Pulse Inpu s............................................................................................................................................. 11
2.7 4-20mA High Accuracy 24bi Analog Inpu s............................................................................................. 12
2.7.1 Analog Inpu Block Diagram.........................................................................................................................................................12
2.7.2 Analog Inpu Field Wiring.............................................................................................................................................................13
3 Pico RMU in RTU Mode................................................................................................................14
3.1 RTU Mode Connec ion Pinou Drawing...................................................................................................14
4 Pico RMU in PIU Mode..................................................................................................................15
4.1 PIU Mode Connec ion Pinou Drawing....................................................................................................15
4.2 Digi al Inpu Assignmen .......................................................................................................................... 16
4.3 Digi al Ou pu Assignmen ....................................................................................................................... 17
5 TorqueWrench.............................................................................................................................. 18
5.1 PicoRMU Info Page Informa ion.............................................................................................................. 19
5.1.1 Pulse Inpu s..................................................................................................................................................................................19
5.1.2 Device Informa ion........................................................................................................................................................................19
5.1.3 Digi al Inpu s.................................................................................................................................................................................19
5.1.4 Digi al Ou pu s..............................................................................................................................................................................20
5.1.5 Analog Inpu s................................................................................................................................................................................20
5.1.6 Pressure Correc ion......................................................................................................................................................................20
5.2 PicoRMU Config Page Informa ion.......................................................................................................... 21
5.2.1 Digi al Inpu Inversion...................................................................................................................................................................21
5.2.2 Digi al Ou pu Inversion................................................................................................................................................................21
5.2.3 RS422/485 Config........................................................................................................................................................................22
5.2.4 Fwd/Rev Timeou (secs) – PIU Mode Only..................................................................................................................................22
5.2.5 Modbus Slave Address.................................................................................................................................................................22
5.2.6 Densi ome er Pressure Compensa ion........................................................................................................................................22
5.3 PicoRMU Info Page in PIU Mode............................................................................................................. 23
5.4 Wiring he Isola ed RS422 Conver er...................................................................................................... 24
6 Modbus.......................................................................................................................................... 25
6.1 Modbus Slave Map.................................................................................................................................. 25
6.2 Newflow Modbus Mas er Simula or......................................................................................................... 28
7 Mechanical Dimensions...............................................................................................................29
8 Specifications............................................................................................................................... 30
8.1 Mechanical............................................................................................................................................... 30
8.1.1 DIN Rail Moun ed.........................................................................................................................................................................30
8.1.2 Po ed Uni ....................................................................................................................................................................................30
8.2 Environmen al.......................................................................................................................................... 30
8.3 Power Supply........................................................................................................................................... 30
8.4 Digi al S a us Inpu s................................................................................................................................. 31
8.5 Digi al S a us Ou pu s.............................................................................................................................. 31
8.6 Me er Pulse Inpu s & Period Measuremen .............................................................................................31
8.7 Analog Inpu s........................................................................................................................................... 31
Page 4 of 31 Pico RMU User Manual PicoRMU-UM-R4

1 Introduction
Operational Overview
The Pico RMU is a small footprint Remote Measurement Unit optimized for flow measurement and
meter proving applications.
Features
The Pico RMU is designed to operate as an interface to the Quorum (previously Flow-Cal, Inc) TESTit
& PROVEit validation packages. The following features are included as part of the design of the unit:
•Packaged in either a DIN Rail mounting enclosure, or as a fully potted version for tough
environmental locations.
•All connections are made by pluggable heavy duty 5mm terminal blocks. These can accept
cable of 24AWG to 12AWG.
•Operating temperature range is -40 °F to +185 °F.
•Compatible TESTit & PROVEit RS232 serial interface.
•RS232 port is optically isolated from the internal ground, shared by the analog inputs, to ensure
there are no ground loops which could affect the integrity of operation.
•RS422 port can also be used with TESTit & PROVEit if longer cable lengths are required.
•Digital inputs, digital outputs and pulse inputs are all individually optically isolated.
•The Pico RMU can also be used as a general purpose RTU device, communicating via Modbus
RTU protocol.
•Modbus Master interface provided for connection to a densitometer or Coriolis meter. This
allows the Pico RMU to provide the line pressure to the densitometer or Coriolis meter so that it
can enhance accuracy by correcting the measured density for the effects that pressure has on the
tube stiffness. This runs on the RS-422/485 serial port.
•A Poll Profile File for the Pico RMU is available for the Newflow Modbus Master Simulator.
This allows the Pico RMU to be verified in Modbus mode.
•The free of charge TorqueWrench Windows program can also be used for diagnostic and
configuration purposes.
PicoRMU-UM-R4 Pico RMU User Manual Page 5 of 31

2 Pico RMU I/O
2.1 Field I/O
The Pico RMU has the following Field I/O available:
Field I/O Type Number of
Channels
Pins
Used Isolated Use or Comment
Me er Pulse Inpu s
see 2.6 - Pulse Inpu s
3 6 Yes All inpu s have high
resolu ion period
measuremen and are also
sui able for use wi h a
Densi ome er
Digi al I/P
see 2.4 .- Digi al Inpu s
7 14 Yes Digi al Inpu 7 is also used
as he De ec or/Sphere-
Swi ch inpu
Digi al O/P
see 2.5 - Digi al Ou pu s
5 10 Yes General Purpose, pro ec ed
Ou pu s wi h low sa ura ion,
can drive TTL
Analog Inpu s
see 2.7 - 4-20mA High
Accuracy 24bi Analog Inpu s
8 8+3 No The eigh inpu s are
configured for 4-20mA,
sharing a common ground
RS232 1 3 Yes PROVEi /TESTi In erface
or Modbus RTU
RS422 or RS485 1 5 No Modbus RTU slave
In erface or Modbus Mas er
In erface
To avoid ground loops whilst using the RS422 port, the use of an isolated RS422 converter is
recommended, see 5.4 - Wiring the Isolated RS422 Converter .
Page 6 of 31 Pico RMU User Manual PicoRMU-UM-R4

2.2 Communications
The Pico RMU is equipped with two serial communications ports. One port is an optically isolated
RS232 port intended for direct connection to the Quorum (previously Flow-Cal, Inc) PROVEit and
TESTit proving supervisory programs. If the Pico RMU is not being used with PROVEit, the port is a
slave Modbus RTU link.
The second port is an RS422 port. With full control provided on the enable signals for both the transmit
and receive, the port can also be used in RS485 mode, by connecting the RX+ & TX+ together to
produce the RS485 A signal and connect the RX- & TX- together to produce the RS485 B signal.
2.3 Input Power
The Pico RMU will operate with a supply voltage in the range of 10V to 30V. It consumes around
0.25W, and runs very cool to maximize lifetime and reliability.
2.4 Digital Inputs
There are seven identical high impedance optically isolated Digital Input channels. Each channel has
both surge and reverse voltage protection, the input circuit is shown below. Following recovery of the
signal from the opto-isolator, the signal is fed into the Processor (CPU) where it is digitally processed.
2.4.1 Digital Input Circuit Overview
2.4.2 Digital Input Functional Representation
From an operation perspective, each digital input can be considered as a light bulb with a series diode.
The voltage must be applied in the right polarity but, because they are all individually isolated, the
installer has the freedom to connect them in a number of ways.
A digital input is active when a voltage of the
correct polarity is connected between the two input
connections and the "light bulb" is illuminated
PicoRMU-UM-R4 Pico RMU User Manual Page 7 of 31
− VE
+ VE
To CPU

2.4.3 Digital Input Field Wiring Example
Page 8 of 31 Pico RMU User Manual PicoRMU-UM-R4
DigIn 1
+
−
DigIn 2
+
DigIn 3
+
DigIn 4
+
DigIn 5
+
DigIn 6
+
DigIn 7
+
Independen ly
Powered Ou pu
+24V Supply
Push Bu on
Relay Con ac
Grounded Push Bu on
Grounded Relay Con ac
Open Collec or
Grounded
Sphere Swi ches
24V Re urn
PICO RMU
+
-
−
−
−
−
−
−
To CPU
To CPU
To CPU
To CPU
To CPU
To CPU
To CPU

2.5 Digital Outputs
There are five Digital Outputs provided. Each output channel has a high current output which is surge
and reverse connection protected. Each output is optically isolated from all other I/O points. This
allows it to be connected to either the positive rail to act as a current source or connected to the
negative rail to mimic a grounded open collector output.
Each output also has a highly robust protection circuit that disconnects the load in case of an accidental
overload.
2.5.1 Digital Output Circuit Overview
2.5.2 Digital Output Functional Representation
Each digital output can be considered as the contacts of a relay with a reverse clamp diode.
When the digital output is OPEN, no current will flow from the +ve to the -ve terminals (as long as the
correct polarity is observed). When the contacts are CLOSED, current will flow.
NOTE: The protection device on the Digital Outputs will make current flow if the polarity is
reversed regardless of whether the Pico RMU is powered on or turned off.
2.5.3 Digital Output Field Wiring Example
PicoRMU-UM-R4 Pico RMU User Manual Page 9 of 31
− VE
+ VE
Digi al
Ou pu
+ve
-ve
From he Digi al
Processor Ou pu

2.6 Pulse Inputs
There are three Pulse Input channels. Each is individually opto-isolated and has transient protection and
filtering. They are suitable for meter pulses or frequency mode Densitometers, as all inputs have high
Page 10 of 31 Pico RMU User Manual PicoRMU-UM-R4
Pico-RMU
DigOu 1
DigOu 4
DigOu 3
DigOu 2
DigOu 5
24V Re urn
+24V Supply
Annuncia or
Relay Wi h
Back-EMF Diode
Indica or
−
+
Dig In Op o-coupler
Relay Wi h
Back-EMF Diode
−
+
−
+
−
+
−
+
From
CPU
From
CPU
From
CPU
From
CPU
From
CPU
+
−
−
+

resolution period measurement suitable for use with Densitometers.
PicoRMU-UM-R4 Pico RMU User Manual Page 11 of 31
− VE
+ VE To
CPU
High
Speed
Signal
Recovery
Circui

2.7 4-20mA High Accuracy 24bit Analog Inputs
The Analog section provides eight identical, high accuracy Analog Input measurement circuits, sharing
a common ground. They are all 4-20 mA measurement channels.
24bit sigma-delta Analog to Digital Converter (ADC) technology is used together with a precision
reference.
2.7.1 Analog Input Bloc Diagram
Page 12 of 31 Pico RMU User Manual PicoRMU-UM-R4
120R
120R
120R
120R
120R
120R
120R
120R
Ch1
Ch2
Ch3
Ch4
Ch5
Ch6
Ch7
Ch8
Analog Ground
8 Channel
Analog In 1+
Analog In 2+
Analog In 3+
Analog In 4+
Analog In 5+
Analog In 6+
Analog In 7+
Analog In 8+
3 x Analog
Da a
Grounds Reference
To
CPU
24 Bi ADC

2.7.2 Analog Input Field Wiring
PicoRMU-UM-R4 Pico RMU User Manual Page 13 of 31
Tu
120 R
+
120 R
+
120 R
+
120 R
+
120 R
+
AnIn 1-8
120 R
+
120 R
+CH1
CH2
CH3
CH4
CH5
CH6
CH7
CH8
GND
GND
GND
Td
Pu
Pd
D
120 R
+
+24V SUPPLY
24V RETURN

3 Pico RMU in RTU Mode
3.1 RTU Mode Connection Pinout Drawing
Page 14 of 31 Pico RMU User Manual PicoRMU-UM-R4
+ ‒ + ‒ + ‒ + ‒ + ‒ + ‒ + ‒+ ‒ + ‒+ ‒+ ‒
‒ +‒ +
‒ +‒ +‒ +
‒ +‒ +‒ +
‒ + + + + + + + + +
1 2 3 4 5 6 7
Digi al Inpu s
1 2 3 4 5
Digi al Ou pu s
A B
C
Pulse
Inpu s
S a us
Comms
8 7 6 5 4 3 2 1
Analog
Inpu s
Analog
Ground
DC Power In
GND GND RX TX
RS232
TX-
RX-
RX+ TX+ SCN
RS422
Power

4 Pico RMU in PIU Mode
When the Pico RMU detects PIU formatted commands are being received, rather than Modbus polls, it
automatically switches into PIU operational mode.
4.1 PIU Mode Connection Pinout Drawing
PicoRMU-UM-R4 Pico RMU User Manual Page 15 of 31
+ ‒ + ‒ + ‒ + ‒ + ‒ + ‒ + ‒+ ‒ + ‒+ ‒+ ‒
‒ +‒ +‒ +‒ +
‒ +‒ +‒ +‒ +
‒ + + + + + + + + +
1 2 3 4 5 6 7
Digital Inputs
1 2 3 4 5
Digital Outputs
A B
C
Pulse
Inpu s
S a us
Comms
8 7 6 5 4 3 2 1
Analog
Inpu s
Analog
Ground
DC Power In
GNDGND RX TX
RS232
TX-
RX-
RX+ TX+ SCN
RS422
Power
Re urn Pis on
La ched Launch
Forward Command
Reverse Command
Launch Pulse
PIU MODE Digi al Inpu s & Ou pu s

In PIU mode, the functions of the Digital Inputs and Digital Outputs are pre-selected as shown on the
previous page. The selection of the Pulse Input channel and the Analog Input channels can be chosen
within PROVEit.
The connection to the PC running the prover software package usually utilizes the RS232 link, and the
baud rate and other serial communications settings are fixed. For installations that need longer cables or
better noise immunity, the RS422 port can be used for the PIU communications as long as it is
configured to 9600 baud to match the setting of PROVEit.
The spare serial communications port can be used for two purposes:
1. It can be used with TorqueWrench to check or diagnose any problems with the field
connections as it gives a clear indication of the current status of all of the inputs and outputs.
2. It can also be used to configure the Pico RMU options, such as inverting any or all of the
Digital Inputs & Digital Outputs, selecting a Forward and Reverse command timeout for the 4-
way valve in Bi-Directional prover mode or configuring the Densitometer pressure correction.
4.2 Digital Input Assignment
In PIU mode, the use of the Digital Inputs has been allocated as shown in the table below.
Digital
Inputs Description PROVEit Function
DIGIN1 Forward Reset This input resets the alternating Forward Command and Reverse
Command outputs for the 4-way valve control, to the forward
direction.
This information is not transmitted to PROVEit.
DIGIN2 Forward Endstop If the BiDi Prover 4-way valve has a switch to indicate the valve
has completed its forward travel, it can be connected here.
DIGIN3 Reverse Endstop If the BiDi Prover 4-way valve has a switch to indicate the valve
has completed its reverse travel, it can be connected here.
DIGIN4 Fault Detect The state of this input is transmitted directly to PROVEit.
DIGIN5 Leak Detect The state of this input is transmitted directly to PROVEit.
DIGIN6 Prover Ready The state of this input is transmitted directly to PROVEit.
DIGIN Detector Switch Detector Switch also known as Volume Pulse
The detector switch input is used to trigger the various internal
counters and drives the prover sequence along.
Page 16 of 31 Pico RMU User Manual PicoRMU-UM-R4

4.3 Digital Output Assignment
In PIU mode, the use of the Digital Outputs has been allocated as shown in the table below.
Digital
Outputs Description PROVEit Function
DIGOUT1 Launch Pulse Launch (500ms duration pulse).
This output is triggered directly by PROVEit.
This output is used with mechanically driven Small Volume
Provers.
DIGOUT2 Forward
Command
The Forward Command and Reverse Command outputs are
triggered alternatively by the PROVEit Launch request. These
are intended for use with bi-directional provers. The Forward or
Reverse Command signals stay active until either the associated
Endstop input signal is detected or the Prover FWD/REV
Timeout is exceeded.
DIGOUT3 Reverse
Command
Reverse Command for bi-directional provers.
See Forward Command above.
DIGOUT4 Latched Launch This output is used with hydraulically driven Small Volume
Provers. The Latched Launch output will stay active until the
second detector has been triggered.
DIGOUT5 Return Piston Return Piston (500ms duration).
This output is triggered directly by PROVEit.
PicoRMU-UM-R4 Pico RMU User Manual Page 17 of 31

5 TorqueWrench
The TorqueWrench Windows program can be used to check the installation and that appropriate values
are being seen. In addition, the Config tab allows the digital inputs and digital outputs to be inverted.
These settings are stored in non-volatile memory, so will be remembered after a power cycle.
The TorqueWrench program is a single executable program and does not require an installer as it
requires no other files to operate.
The file can be placed in any folder or directory, including the desktop, a USB memory stick or a
network drive. When the program is first launched, it will create a TorqueWrench.ini file in the same
directory as the executable is run from. This file stores information such as the serial port settings.
TorqueWrench communicates with the Pico RMU by means of Modbus RTU only.
The screenshot directly below shows the screen after launching the application. The initial view
displays the Pico RMU Information page (PicoRMU Info) .
Page 18 of 31 Pico RMU User Manual PicoRMU-UM-R4

5.1 PicoRMU Info Page Information
The following describes in more detail the information shown on the PicoRMU Info screen on the
previous page.
5.1.1 Pulse Inputs
The top left of the screen shows the frequency to 6 significant digits for the three pulse input channels.
It also displays the Pulse Count of each channel since the Pico RMU was powered on.
5.1.2 Device Information
The top right of the screen has six information fields. These are:
1. S/No The Pico RMU unique Serial Number
2. Version [CRC] This is the firmware version with the checksum in square brackets
3. Tick ms This is the Pico RMU up-time in milliseconds
4. Pkt Count This shows the number of Modbus messages decoded by TorqueWrench
5. Update Count This indicate the number of updates to all eight Analog Inputs
6. RMU Temperature This is the internal temperature of the ADC voltage reference
5.1.3 Digital Inputs
The center left of the screen shows a mimic of the status for each of the Digital Inputs, Ch1 to Ch .
These seven fields display two pieces of information for each digital input.
The first word (OFF or ON) shows the electrical levels going into the digital input circuit, and indicates
if the "light bulb" is turned on or off.
A digital input is OFF unless a voltage of the correct
polarity is connected between the two input
connections. Then the "light bulb" would be
illuminated and the input would report ON.
The second word (LO or HI) shows the input logic state following the Digital Input Invert function for
each channel described in section 5.2.1 - Digital Input Inversion .
Input Level No Inversion Inversion Selected
Input Off:
less han 1.5V
across he erminals OFF-LO OFF-HI
Input On:
more han 5V
across he erminals ON-HI ON-LO
PicoRMU-UM-R4 Pico RMU User Manual Page 19 of 31

5.1.4 Digital Outputs
The middle of the screen shows a mimic of the status for each of the Digital Outputs, Ch1 to Ch5.
These five fields show the commanded value sent to the Digital Output Circuitry. The actual output
may be opposite the software value, if the Digital Output Invert function has been enabled for that
channel.
When the digital output is OPEN no current will
flow from the +ve to the -ve terminals. When the
contacts are CLOSED, current will flow as long as
the correct polarity is observed.
NOTE:
The protection device on the Digital Outputs will
make current flow if the polarity is reversed
regardless of whether the Pico RMU is powered on
or turned off
5.1.5 Analog Inputs
The center right of the screen shows the Analog Input current, measured in milli-amps (mA) for each of
the eight channels Ch1-Ch8, shown to 4 decimal places.
5.1.6 Pressure Correction
The bottom right of the screen has a single data field titled Pressure Correction.
The figure displayed is calculated by applying the scaling values (the pressure @ 4 mA and 20 mA) to
the analog reading of the selected channel, as shown in the PicoRMU Config screen described in 5.2.6 -
Densitometer Pressure Compensation.
This calculated value can be transmitted to a Densitometer or Coriolis meter so the meter can correct its
density measurement due to the effects of pressure on the measuring tube stiffness.
Page 20 of 31 Pico RMU User Manual PicoRMU-UM-R4
− VE
+ VE
Digi al
Ou pu