Pyxis CR-301 User manual

CR-301 User Manual [email protected] | [phone]

CR-301 Corrosion Rate Sensor
User Manual
April 15, 2021
Rev. 1.01
Pyxis Lab, Inc.
1729 Majesc Dr. Suite 5
Lafayee, CO 80026 USA
www.pyxis-lab.com
© 2017 Pyxis Lab, Inc.
Pyxis Lab Proprietary and Condenal

Table of Contents
1 Introducon 2
1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 uPyxis APP Conguraon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Specicaons 4
3 Unpacking the Instrument 5
3.1 Standard Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2 Oponal Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Installaon 6
4.1 Wiring ................................................. 7
4.2 Connecng via Bluetooth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5 Instrument Overview 11
5.1 Test Metal Electrodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.2 Default Sensor Sengs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.3 Conrm 4–20mA Output to MPY using the Calibraon Check Caps . . . . . . . . . . . . . . . 13
6 Setup and Calibraon with uPyxis® Mobile App 14
6.1 Download uPyxis® Mobile App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.2 Connecng to uPyxis® Mobile App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.3 Reading Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.4 Seng Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7 Setup and Calibraon with uPyxis® Desktop App 18
7.1 Install uPyxis® Desktop App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
7.2 Connecng to uPyxis® Desktop App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
7.3 Informaon Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
7.4 Reading Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
7.5 Seng Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
8 Outputs 21
8.1 4–20 mA Output Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
8.2 Communicaon using Modbus RTU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
9 Sensor Maintenance and Precauon 21
10 Regulatory Approval 22
11 Contact Us 22

Warranty Informaon
Condenality
The informaon contained in this manual may be condenal and proprietary and is the property of Pyxis
Lab, Inc. Informaon disclosed herein shall not be used to manufacture, construct, or otherwise reproduce
the goods described. Informaon disclosed herein shall not be disclosed to others or made public in any
manner without the express wrien consent of Pyxis Lab, Inc.
Standard Limited Warranty
Pyxis Lab warrants its products for defects in materials and workmanship. Pyxis Lab will, at its opon, repair
or replace instrument components that prove to be defecve with new or remanufactured components
(i.e., equivalent to new). The warranty set forth is exclusive and no other warranty, whether wrien or oral,
is expressed or implied.
Warranty Term
The Pyxis warranty term is thirteen (13) months ex-works. In no event shall the standard limited warranty
coverage extend beyond thirteen (13) months from original shipment date.
Warranty Service
Damaged or dysfunconal instruments may be returned to Pyxis for repair or replacement. In some in-
stances, replacement instruments may be available for short duraon loan or lease.
Pyxis warrants that any labor services provided shall conform to the reasonable standards of technical com-
petency and performance eecve at the me of delivery. All service intervenons are to be reviewed and
authorized as correct and complete at the compleon of the service by a customer representave, or des-
ignate. Pyxis warrants these services for 30 days aer the authorizaon and will correct any qualifying
deciency in labor provided that the labor service deciency is exactly related to the originang event. No
other remedy, other than the provision of labor services, may be applicable.
Repair components (parts and materials), but not consumables, provided during a repair, or purchased
individually, are warranted for 90 days ex-works for materials and workmanship. In no event will the in-
corporaon of a warranted repair component into an instrument extend the whole instrument’s warranty
beyond its original term.
Warranty Shipping
A Repair Authorizaon (RA) Number must be obtained from Pyxis Technical Support before any product can
be returned to the factory. Pyxis will pay freight charges to ship replacement or repaired products to the
customer. The customer shall pay freight charges for returning products to Pyxis. Any product returned to
the factory without an RA number will be returned to the customer. To receive an RMA you can generate a
request on our website at hps://pyxis-lab.com/request-tech-support/.
Pyxis Technical Support
Contact Pyxis Technical Support at [phone], [email protected], or by lling out a request for
support at hps://pyxis-lab.com/request-tech-support/.
CR-301 User Manual [email protected] | [phone]

1 Introducon
The Pyxis CR-301 corrosion sensor measures the metal corrosion rate in an aqueous environment based on
the principle of linear polarizaon resistance (LPR). A small polarizaon DC voltage is applied to two test
metal electrodes and the resulng current is measured by the sensor. The polarizaon resistance value is
calculated from the measured current and the applied polarizaon voltage. The metal corrosion rate in the
unit of thousandths of inch per year (or mils per year, MPY) is then determined as:
MP Y =B/Rp (1)
where Rp is the polarizaon resistance (LPR) and B the proporonal constant.
To calculate Rp originated from the electrochemical reacon at the metal water interface, the CR-301 sensor
subtracts the soluon resistance Rs due to the test soluon conducvity from the total resistance measured
between the two test electrodes. The CR-301 sensor accurately measures the test soluon conducvity us-
ing the two test electrodes and the bipolar pulse technique, which has been successfully used in other Pyxis
conducvity sensors and handheld meters.
A challenge of using the LPR method to measure corrosion rate below 0.01 MPY is to measure electric
current in the range of pico and nano-amperes. The CR-301 sensor adapts a range of techniques that are
pracced in our uorometers where low pico ampere current is measured. These techniques include elec-
tromagnec interference shielding, special analog circuit designs and digital signal processing. The propor-
onal constant B has a theorecal value for a given metal type and size. The CR-301 assumes B equal to
1.24 MPY∙Ω for a 5 cm2mild steel electrode, which is a typical value that has been used in many LPR cor-
rosion researches. This proporonal constant may be also referred to as the alloy factor of the test metal
and normalized to 1.0 for the steel electrode for convenience. It can be adjusted by the user to account for
variaons in a real applicaon environment.
To determine the corrosion situaon of real process equipment is not a simple maer. The corrosion rates
for various metal surfaces contacng aqueous uids in a process depends on many parameters, including
the corrosivity pertaining to the chemistry of the aqueous uid, physical parameters such as temperature
and the velocity of the uid, and the metallurgical composion of the process equipment itself. Because
of this, the corrosion rate measured by the CR-301 should not be used alone to predict or assess the real
corrosion rate of the process equipment. Nevertheless, the science of using the LPR technique to quanfy
the corrosion rate has been well established. The corrosion rate measured by the CR-301 sensor can be
used to understand the corrosivity trend of the aqueous uid over a period and its correlaon to changes
in the process parameters.
Measuring corrosion rate using a weight loss corrosion coupon is sll widely pracced in many industry
applicaons. LPR is an instantaneous method compared with the corrosion coupon method. It can indi-
cate a change in corrosion rate in a me scale of a few minutes. In theory, a me averaged corrosion rate
measured by the Pyxis LPR sensor should agree with that from the weight loss coupon method if both are
pracced according to the common pracces known in the industry. For monitoring mild steel corrosion
rate in an industrial cooling water system, one could also treat the LPR metal electrode itself as the weight
loss corrosion coupon and compare the corrosion rate calculated from the weight loss of the electrode to
the averaged LPR corrosion rate in order to calibrate the LPR corrosion rate by adjusng the alloy factor.
The electrochemical noise measurement has long been used to quanfy the localized corrosion or ping
corrosion rate. The CR-301 sensor measures the short circuit electric current owing through the electrodes
CR-301 User Manual [email protected] | [phone]

between the two LPR measurements. The Pyxis sensor rst applies a signal process algorithm to remove
high frequency noise in the acquired electrochemical current data for a period of 3 minutes and then cal-
culates the standard deviaon of the processed data set. The standard deviaon calculated is scaled to
generate a localized corrosion index. In such a scaling, the index value for a 304-stainless steel electrode
immersed in a 10% ferric chloride soluon at 72°F is arbitrarily dened as 100. The real me electrochem-
ical current noise data are graphically displayed in the Pyxis display panel, an oponal item that can be
purchased separately. With the graphic trend, the noise paern and magnitude can be easily analyzed
visually.
1.1 Features
The CR-301 is a standalone high temperature and high pressure rated LPR corrosion sensor that can be
powered by a 24 VDC power source such as an exisng controller, PLC or DCS. The sensor is composed of
Titanium and PEEK (Polyether Ether Ketone) making it highly resilient to extreme process environments,
temperatures and pressures. The CR-301 also oers an expanded general corrosion range as high as 995
mils per year and localized corrosion index as high as 100.
When used with the provided MA-CR Pyxis Bluetooth Adapter, the CR-301 must be congured via the uP-
yxis APP for Mobile or Desktop devices. The uPyxis app is used to congure the CR-301 for the metallurgy
desired, assign a sensor idencaon name, obtain live sensor readings. Default measurement ranges and
alloy factors will be applied to the CR-301 via the uPyxis APP when the user selects the metallurgy desired.
Custom alloy factors and ranges of measurement may be adjusted if desired. Addional diagnosc infor-
maon is available and can be used for determining the sensor performance or the need for maintenance.
• An-electromagnec interference (an-EMI) design with Titanium sensor body
• 2x 4–20mA Outputs (General Corrosion and Localized Corrosion)
• RS-485 Modbus Output
• Integrated Cooling Fin Design for High Temperature Applicaons
• Bluetooth connecvity to uPyxis app when used with MA-CR Adapter
• Default 4–20mA Output scales and Alloy Factors assigned for selected metallurgy via uPyxis
• Customizaon of Alloy Factor and upper MPY / Index (20mA) scale as desired via uPyxis
• Ultra-low general corrosion rate detecon down to 0.001 MPY
1.2 uPyxis APP Conguraon
The uPyxis APP manages all Pyxis portable meter and inline sensors on mobile and desktop devices, includ-
ing Apple iPhones and Samsung Android smartphones. When connected to the Pyxis CR series corrosion
rate sensors, the uPyxis APP enables users to congure the sensor for the specic metallurgy desired as well
as name the sensor, system and data log frequency in addion to oering live corrosion rate data trend-
ing. For wireless access to CR-301, the MA-CR Bluetooth Adapter will be required. One MA-CR adapter is
provided with the purchase of each CR-301.
*NOTE*The uPyxis Mobile APP is evolving rapidly and users can nd the latest version at
no cost on Apple iStore or Google Play. The uPyxis Desktop APP may be downloaded at
hps://pyxis-lab.com/upyxis/
CR-301 User Manual [email protected] | [phone]

2 Specicaons
Table 1. CR-301 Specicaons
Item CR-301
P/N 51021
General Corrosion Range - MPY
(4–20mA Output)
0.001–995
(Default Assigned MPY is Customizable Via uPyxis)
Resoluon 0.001 MPY or 1% of Reading
Localized Corrosion Range — Index
(4–20mA Output)
0.001–100
(Default Assigned Index is Customizable Via uPyxis)
Conducvity Compensaon 10–50,000uS/cm
Reading Interval 3 to 1440 Minutes
(>3 Minutes Required for Localized Corrosion Data)
Alloy Factor Range 0 — 3
(Adjustable Default Assigned via uPyxis on Metallurgy
UNS Code)
Power Supply 24V DC,2W
Output Output RS-485 and 4–20 mA Dual Output
Weight 1150g
Dimensions (L x D) 280mm L X 52mm D
Installaon 3/4” NPT
Enclosure Material Titanium + PEEK
Operang Pressure Up to 500 psi (34.5 bar)
Operang Temperature -10 — 240°C (14 — 464°F)
Storage Temperature -20 — 70°C (-4 — 158°F)
Cable Format 8Pin - 5 . (1.5 m),
Extension Cables Available
Protecon IP68
Regulaon CE / RoHS
CR-301 User Manual [email protected] | [phone]

3 Unpacking the Instrument
Remove the instrument and nd the standard accessories from the shipping container as listed below. In-
spect each item for any damage that may have occurred during shipping. Verify that all accessory items are
included. If any item is missing or damaged, please contact Pyxis Lab Customer Service at service@pyxis-
lab.com
3.1 Standard Accessories
3.1.1 CR-301 - Wired / 24VDC LPR Corrosion Sensor Package (P/N 51021)
• The package should include one CR-301 sensor, a 5-foot extension cable terminated with connectors,
a 2-foot ying lead cable with one end terminated with a connector
• One Bluetooth Adapter for CR-301 (P/N: MA-CR)
• One Bluetooth Adapter for PC (P/N: MA-NEB)
• One pair of copper (P/N: 51003) and one pair of mild steel electrodes (P/N: 51002)
• One 2.0 MPY Calibraon Check/vericaon cap (P/N: 51010)
• One 0.1 MPY Calibraon Check/vericaon cap (P/N: 51011)
• Operaon Manual is also available for download at hps://pyxis-lab.com/support/
3.2 Oponal Accessories
Figure 1.
CR-301 User Manual [email protected] | [phone]

4 Installaon
The CR-301 sensor is shipped without the electrodes installed. A pair of copper and mild steel electrodes
are included in the package. Remove the O-rings in the electrode package and place an O-ring to each
threaded rod on the sensor. Fasten the electrodes to the threaded rods to slightly compress the O-ring on
the boom of the threaded rod. Clean the electrodes with isopropanol to remove any oil or other foreign
materials on the electrode surfaces.
*NOTE*Pyxis recommends wearing latex gloves when installing the electrodes to avoid
contaminaon with skin oils.
Figure 2. CR-301 Installaon in the sample ow line
The sensor probe shall be inserted into a pipe via a 3/4 - inch threaded tee. The corrosion rate measured
by the CR-301 sensor may be aected by the posion of the two-test metal electrodes in relaon to the
water ow. The electrodes should be fully immersed in the water sample and away from any turbulence.
For the best performance, the two-test metal electrodes should be installed to be parallel to the ow and
maintain a symmetry between the electrodes with respect to the ow environment as much as possible.
Figure 3. CR-301 Dimensions in Inch (mm)
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4.1 Wiring
Follow the wiring table below to connect the CR-301 sensor to a controller. The Grey wire and the Brown
wire are the power ground and internally connected. The Grey wire can be used for the 4–20 mA return.
The Blue and Yellow wires are for RS-485 connecon only and only required if using Modbus protocol. The
Green earth ground wire should be connected to the controller chassis ground if it is available.
Table 2.
Wire Color Designaon
Red 24V +
Brown 24V Power ground
White General corrosion rate, 4–20mA +
Pink Localized corrosion rate, 4–20mA +
Gray*4–20mA -
Blue RS-485 A
Yellow RS-485 B
Green Shield, earth ground
*Internally connected to the power ground
The CR-301 comes with 4–20mA transmiers embedded in the sensor body. It provides outputs on two
channels of 4–20mA signals that represent general corrosion rate and localized corrosion rate respecvely.
Default alloy factors and corrosion rate scales in mils per year (MPY) are pre-programmed for each metal-
lurgy in the uPyxis APP as outlined in the Test Metal Electrode Default Sengs table. When a metallurgy is
selected from the drop-down list, the uPyxis APP will automacally assign default alloy factor and 4–20mA
scales for both general and localized corrosion. The corrosion rates scales provided by uPyxis are commonly
appropriate for the range of typical corrosion observed of the selected metallurgy, however, the user may
desire to alter the alloy factor or corrosion rate scale for any selected metallurgy in the uPyxis APP.
The user may alter the 4–20 mA output from the CR-301 to a desired corrosion rate in the unit of MPY
by seng up one of three congurable parameters. The congurable parameters include 1) alloy factor,
2) the sensor’s 4–20 mA range and 3) the controller’s 4–20 mA range. The rst two reside in the CR-301
sensor itself and can be congured by using the uPyxis app.
CR-301 User Manual [email protected] | [phone]

See below for wiring illustraons of the CR-301 sensor to several common controllers.
Figure 4. Typical wiring for WalChem W600
Figure 5. Typical wiring for WalChem W900 (4-wire loop conguraon)
CR-301 User Manual [email protected] | [phone]

Figure 6. Typical wiring for WalChem WebMaster One
Figure 7. Typical wiring for Advantage Controls MegaTron SS
*NOTE*To get a Ping signal, a jumper wire is needed from 4–20mA Input 2- to power
-24V.
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Figure 8. Typical wiring for Advantage Controls MegaTronXS
*NOTE*To get a Ping signal, a jumper wire is needed from 4–20mA Input 3- to power
-24V.
4.2 Connecng via Bluetooth
A Bluetooth adapter (P/N: MA-CR) can be used to connect the CR-301sensor to a smart phone with the
uPyxis® Mobile App or a computer with the uPyxis® Desktop App. The power should be sourced from a 24
VDC power terminal of a controller. If a controller is not available, the user may also use Pyxis PowerPACK-1
or PowerPACK-4 as an alternave to both an external power supply and a Bluetooth adapter. PowerPACK
from Pyxis Lab oers external power, Input/Output signal, and Bluetooth connecvity.
Figure 9. Bluetooth connecon to CR-301 sensor
CR-301 User Manual [email protected] | [phone]

5 Instrument Overview
5.1 Test Metal Electrodes
Pyxis provides 5-cm2(0.736 square inch) metal electrodes, commonly used in the LPR corrosion measure-
ment applicaons. The common names, UNS codes, and alloy factors are listed the table below.
Figure 10. Test Metal Electrode Dimensions, Inch [mm]
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Table 3. Test Metal Electrode Default Sengs
Common Designaon UNS Alloy Factor
Default 4–20mA
General
Corrosion Scale
(MPY)
Default 4–20mA
Localized
Corrosion Scale
(Index)
Aluminum AA1100 A91100 0.94 0–50 0–100
Aluminum AA6061 A96061 0.94 0–50 0–100
Aluminum AA2024 A92024 0.86 0–50 0–100
Cu/Ni - 70/30 C71500 1.50 0–5 0–10
Copper 110 ETP C11000 2.00 0–5 0–10
CDA 687 Aluminum
Brass Arsenical C68700 1.62 0–5 0–10
CDA 642 Aluminum
Silicon Bronze C64200 1.48 0–5 0–10
Arsenical Admiralty
Brass CDA443 C44300 1.67 0–5 0–10
Phosphorized Admiralty
Brass CD445 C44500 1.68 0–5 0–10
Pipe Grade Carbon Steel A135 1.00 0–50 0–100
Mild Steel C1010 G10100 1.00 0–50 0–100
Mild Steel C1015 G10150 1.00 0–50 0–100
Mild Steel C1018-C1020 G10180 1.00 0–50 0–100
Mild Steel C1080 G10800 1.00 0–50 0–100
Stainless Steel 304 S30400 0.89 0–2.5 0–10
Stainless Steel 304L S30403 0.89 0–2.5 0–10
Stainless Steel 316 S31600 0.90 0–2.5 0–10
Stainless Steel 316L S31603 0.90 0–2.5 0–10
Duplex Stainless 2205 -
F51 S31803 0.90 0–2.5 0–10
Duplex Stainless 2507 -
F53 S32750 0.90 0–2.5 0–10
Common Lead L50045 2.57 0–2.5 0–1
*NOTE*Metal electrodes with a dierent length and a slightly dierent diameter may be
used with the CR-301 sensor if the electrodes have a 4-40 internal thread and has a surface
are of 5 cm2. The alloy factor for a given metal alloy is proporonal to the surface area of
the electrode. If an electrode with a surface area dierent than 5 cm2(0.736 square inch)
is used, the user will need to calculate the proper alloy factor according to the surface area
and the default 5cm2alloy factor listed above.
CR-301 User Manual [email protected] | [phone]

5.2 Default Sensor Sengs
The default 4–20 mA current outputs for mild steel are scaled as:
• 4 mA = 0 MPY or 0 localized corrosion index
• 20 mA = 50 MPY (general corrosion)
• 20 mA = 100 Index (localized corrosion)
The sensor is congured to measure the corrosion of mild steel by default. A default alloy factor and output
scales for both general and localized corrosion will be assigned by uPyxis. These values may be altered by
the user if desired. For measuring the corrosion rate of steel, the user just needs to scale 20 mA = 50 MPY
in the controller. Please refer to the Test Metal Electrode Default Sengs table for a list of all metallurgies
and preprogrammed default alloy factors and 4–20mA output scales.
5.3 Conrm 4–20mA Output to MPY using the Calibraon Check Caps
The CR-301 is provided with one 2.0 MPY and one 0.1 MPY- calibraon check/vericaon caps. These caps
are designed to generate a known MPY value when connected to the uPyxis APP and when the sensor is
congured with the uPyxis Default Sengs assigned. These corrosion vericaon caps will work regardless
of which metallurgy is applied to the corrosion sensor and simply establish a known electrical current to
“simulate’ a specic MPY value. When the controller is scaled to match the uPyxis default sengs, these
caps will generate a “TEST” signal to conrm the controller reads properly.
*NOTE*Please note that when conducng a test with the calibraon vericaon caps, the
user should allow up to 15 minutes for the nal corrosion value to stabilize.
Follow the steps below to congure the controller’s 4–20 mA range:
1. Install two new test electrodes (example Steel or Copper)
2. Plug the sensor to the calibraon appropriate calibraon check cap and wait for at least for 15 minutes
to allow the sensor to carry out three complete measurements (Figure ??).
3. Conrm the controller’s analog input 4–20mA scale is programmed correctly so that the corrosion
rate value on the controller matches with the value marked on the calibraon cap.
Figure 11. Plug the sensor into the calibraon check cap
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6 Setup and Calibraon with uPyxis® Mobile App
The default conguraon of the CR-301 sensor before shipping is to measure the corrosion rate of mild
steel. The alloy factor was set to be the theorecal value of iron. The sensor can be congured for other
metals with appropriate alloy factors and the 4–20mA scale sengs for general and localized corrosion
rates using the uPyxis® Mobile or Desktop App.
6.1 Download uPyxis® Mobile App
Download uPyxis® Mobile App from Apple App Store or Google Play.
Figure 12. uPyxis® Mobile App installaon
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6.2 Connecng to uPyxis® Mobile App
Connect the CR-301 sensor to a mobile smart phone according to the following steps:
1. Open uPyxis® Mobile App.
2. On uPyxis® Mobile App, pull down to refresh the list of available Pyxis devices.
3. If the connecon is successful, the CR-301 and its Serial Number (SN) will be displayed (Figure 13).
4. Press on the CR-301 sensor image.
Figure 13.
CR-301 User Manual [email protected] | [phone]

6.3 Reading Screen
When connected, the uPyxis® Mobile App will default to the Reading screen. From the Reading screen,
you can perform a calibraon by pressing on Slope Calibraon. Follow the screen instrucons for each
calibraon step.
Figure 14.
CR-301 User Manual [email protected] | [phone]

6.4 Seng Screen
From the Seng screen, you can set the Reading Interval, the Metal Selecon, the corrosion MPY value
for 20 mA, the ping value for 20 mA, two smoothing factors, and a password for the device. Be sure to
press Apply Sengs to save any changes.
Figure 15.
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