Pyxis ST-765SS Series User manual

ST-765SS-Br
Bromine +pH
Multiparameter Sensor
User Manual
January 30, 2023
Rev. 1.3
Pyxis Lab, Inc.
1729 Majestic Dr. Suite 5
Lafayette, CO 80026 USA
www.pyxis-lab.com
© 2017 Pyxis Lab, Inc.
Pyxis Lab Proprietary and Confidential

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Table of Contents
1. Introducing the Pyxis ST-765SS-Br Sensor ...................................................................................... 4
1.1 Specifications ................................................................................................................................. 5
1.2 Unpacking the ST-765SS-Br ............................................................................................................ 5
1.3 Standard Accessories ..................................................................................................................... 6
1.4 Optional Accessories ...................................................................................................................... 6
2. Dimension & Installation ................................................................................................................ 7
3. Quick 4-20mA Start Up................................................................................................................... 8
4. Calibration and Diagnosis ............................................................................................................. 13
4.1 Calibration and Diagnosis by uPyxis Mobile App ......................................................................... 13
4.1.1 Bromine Calibration.............................................................................................................. 14
4.1.2 pH Calibration....................................................................................................................... 16
4.1.3 4-20mA Span ........................................................................................................................ 17
4.1.4 Diagnosis............................................................................................................................... 17
4.2 Calibration and Diagnosis by uPyxis Desktop App ....................................................................... 18
4.2.1 Bromine Calibration .............................................................................................................. 21
4.2.2 pH Calibration....................................................................................................................... 22
4.2.3 4-20mA Span ........................................................................................................................ 23
4.2.4 Diagnosis............................................................................................................................... 24
4.3 Calibration on the Controller........................................................................................................ 24
5. Modbus RTU .................................................................................................................................. 24
6. Sensor Cleaning and Maintenance .............................................................................................. 25
6.1 Other Common Troubleshooting Issues ....................................................................................... 25
7. Replacing pH and Oxidizer Electrode Head................................................................................... 26
8.Contact Us .................................................................................................................................... 27

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Warranty Information
Confidentiality
The information contained in this manual may be confidential and proprietary and is the property of Pyxis
Lab, Inc. Information disclosed herein shall not be used to manufacture, construct, or otherwise reproduce
the goods described. Information disclosed herein shall not be disclosed to others or made public in any
manner without the express written consent of Pyxis Lab, Inc.
Standard Limited Warranty
Pyxis Lab warrants its products for defects in materials and workmanship. Pyxis Lab will, at its option, repair
or replace instrument components that prove to be defective with new or remanufactured components
(i.e., equivalent to new). The warranty set forth is exclusive and no other warranty, whether written or oral,
is expressed or implied.
Warranty Term
The Pyxis warranty term for the ST-765SS Series sensor body is thirteen (13) months from original
shipment from Pyxis. The Pyxis warranty term for the EH-765 (electrode reference head) installed on the
ST-765SS Series sensor body is six (6) months from original shipment from Pyxis. In no event shall the
standard limited warranty coverage extend beyond this timeline from original shipment date.
Warranty Service
Damaged or dysfunctional instruments may be returned to Pyxis for repair or replacement. In some in-
stances, replacement instruments may be available for short duration loan or lease.
Pyxis warrants that any labor services provided shall conform to the reasonable standards of technical com-
petency and performance effective at the time of delivery. All service interventions are to be reviewed and
authorized as correct and complete at the completion of the service by a customer representative, or des-
ignate. Pyxis warrants these services for 30 days after the authorization and will correct any qualifying
deficiency in labor provided that the labor service deficiency is exactly related to the originating 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-
corporation of a warranted repair component into an instrument extend the whole instrument’s warranty
beyond its original term.
Warranty Shipping
A Repair Material Authorization (RMA) 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 Request Return or Repair - Pyxis Lab, Inc. (pyxis-lab.com)
Pyxis Technical Support
Contact Pyxis Technical Support at [phone] ext. 2, [e-mail]

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1. Introducing the Pyxis ST-765SS-Br Sensor
Description
The Pyxis ST-765SS-Br is a stainless-steel multi-parameter membrane-
less sensor based on unique electrochemical principles to determine
Bromine plus pH and temperature of water. This sensor incorporates
Pyxis' advanced technology in the field of bare-gold electrochemical
detection. The ST-765SS-Br can simultaneously compensate for
temperature and pH in the measurement of Bromine based on real-time
conditions present in the application of use. This unique internal
compensation results in a highly accurate oxidizer measurement
consistent with DPD wet chemistry methodology as high as a pH of 9.0+
and is compliant with USEPA – 334.0 and ISO-7393 guidelines.
The ST-765SS-Br sensor offers a replaceable, front loading reference
electrode assembly that has been independently developed by Pyxis Lab
eliminating the shortcomings associated with membranes and gel
replacement while offering reduced polarization time on startup with an
electrode life span potential of up to 2-years. The flat front-end design
of the ST-765SS-Br makes this platform less prone to contamination or
fouling and is easy to clean. The ST-765S-Br sensor body is composed of
304 stainless steel and is well suited for aggressive environments.
The ST-765SS-Br sensor offers 2x 4-20mA and RS-485 Modbus outputs
and is Bluetooth 5.0 enabled when used in conjunction with the MA-CR
Bluetooth Adapter. This four-electrode composite sensor provides three
measured parameters including Bromine, pH and temperature with one
sensor equipped with fully integrated 2x 4-20mA and RS-485 Modbus
outputs. ST-765SS-Br is uniquely designed for rapid and precise
monitoring of cooling and process water applications utilizing Bromine.
It should only be used in conjunction with the FR-300-PLUS self-brushing
flow reservoir for challenging or dirty water applications.
Key Features
•Real-Time pH + Oxidizer (0-5ppm) Detection
•Dual 4-20mA Outputs (Oxidizer + pH) and RS-485
•Bluetooth Enabled when used with MA-CR Adapter Wireless uPyxis Calibration
•Integrated RTD & pH Compensation to pH 9.0+ of the Oxidizer Value
•Replaceable EH-765 Reference Electrode Assembly – Simple Maintenance
Common Applications
•Cooling Water
•Food & Beverage Process Water
•Industrial Process Water
ST-765SS-Br
Bromine + pH Sensor
EH-765
Replacement Electrode
for all ST-765SS Series

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1.1 Specifications
Item
ST-765SS-Br
P/N
59643
Sensor Body Material
304SS
Oxidizer Range
0.00-5.00 ppm Bromine
Oxidizer Precision
± 0.01mg/L or 1% of the value w/pH compensation up to 9.0+
pH Range
0-14
pH Precision
±0.01 pH
Sample Inlet Pressure
7.25 – 30 psi (0.05 – 0.2MPa)
Installation
FR-300-PLUS Magnetic Coupling Brushing Flow Reservoir
FR-300-PLUS Suggested Flow Rate
200 – 800 mL/minute
FR-300-PLUS Sample Inlet /Outlet
3/8 - inch OD
FR-300-PLUS Operation
24VDC/2.5W Powered Constant ON Mode for Relay Control and RS-485
FR-300-PLUS Rotational Speed
200 RPM – Motorized Brush Preset for Constant Operation
Sensor Power Supply
22 – 26VDC, Power Consumption 2W
Storage Temperature
-7 °C – 60 °C (20 – 140 °F)
Outputs
Dual Isolated 4 – 20 mA Analog Outputs + Isolated RS-485 Digital Output
Dimension (L x D)
Length 8.3 inch (210.8 mm), body diameter 1.4 Inch (35.6 mm)
Weight
530 g (1.16lbs)
Maximum Sensor Pressure
100 psi (6.9 Bar) – Sensor Only
Operating Temperature
4 °C – 49 °C (40 – 120 °F)
Wet Material
UPVC
Rating
IP67, Fully Dustproof & Waterproof
Selectivity
Non-Selective / Cross Sensitive to other Oxidizing Species
Compliance
EPA 334.0 / ISO 7393
Regulation
CE Marked / RoHS
Cables Included
MA-4.9CR Cable (8Pin Adapters – 1.5m)
MA-1.5CR Cable (8 Pin Adapter / Flying Leads – 1.5m)
Typical Electrode Service Life
2 Years
Electrode Warranty
6 Months
Sensor Body Warranty
13 Months
*NOTE* Specifications are subject to change without notice.
1.2 Unpacking the ST-765SS-Br
Remove the instrument and accessories from the shipping container and inspect each item for any damage
that may have occurred during shipping. Verify that all items listed on the packing slip are included. If any
items are missing or damaged, please contact Pyxis Customer Service at [e-mail]

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1.3 Standard Accessories
•One ST-765SS-Br Series sensor (P/N: 59643)
•Includes One MA.4.9CR – (Standard Cable Male-Female 8-Pin Adapters – 1.5m)
•Includes One MA-1.5CR – (Flying Lead Cable Female/Flying Lead 8-Pin Adapter – 1.5m)
•The full instrument manual is available for download at Support Documents - Pyxis Lab, Inc. (pyxis-lab.com)
1.4 Optional Accessories
The following optional accessories can be purchased via [e-mail] or your preferred Pyxis Lab
distributor.
Accessory Name
Item number
EH-765
(Replacement Reference Electrode Head for ST-765SS Series) 53601
FR-300-PLUS
(
Replacement FR-300+ Auto-Brushing Flow Assembly
)
50700-A44
FRP-300-1
(
Replacement Brush Head for FR-300-PLUS
)
50700-A49
MA-AC-7US
(110VAC Power Supply Adapter for FR-300-PLUS with USA Plug)26398
MA-AC-7EU
(230VAC Power Supply Adapter for FR-300-PLUS with EU/DIN Plug)28787
FLOWSWITCH-ROTAMETER
(Adjustable Contact Flow Switch Rotameter 6 - 60 Liter/Hour – Panel Mounted) 21766
MA-CR
(Bluetooth Adapter For use with Pyxis 8-Pin Sensors) MA-CR
MA-NEB
(USB Bluetooth Adapter for use with Laptop or Desktop for uPyxis) MA-NEB
MA-50CR
(Extension Cable-50 feet) 50743
UC-50
(Display + Data Logging Terminal)
43007
pH4-7-10 Combination Pack - Reference Standard Solutions
(500mL/each)
57007
SP-200 OxiPocket
(Pocket All-Oxidizing Disinfectants Colorimeter & Fluorometer)50802
IK-765SS-Br-B
(ST-765SS-Br Sensor + FR-300-PLUS Flow Reservoir + UC-50 Display/Data Logger Panel Mounted) 44074

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2. Dimension
See dimension diagrams below for ST-765SS Series and FR-300-PLUS.
ST-765SS Series Dimensions (mm)
Figure 1. - Dimension of the ST-765SS Series (mm)
FR-300-PLUS Dimensions (mm)
Figure 2. – FR-300-PLUS (mm)

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3. FR-300-PLUS Installation & Operation
The Pyxis FR-300-PLUS is a magnetic coupling motorized brush flow assembly that provides an inline mechanical
cleaning of the ST-765SS Series bare gold electrode enabling sensor accuracy in challenging industrial cooling
and process waters. This unique device enhances the convective mass transport of the oxidizer or reducing agent
analyte to the sensor electrode surface eliminating the need for precision flow control commonly required for
other amperometric sensors on the market. The FR-300-PLUS also provides supplemental deactivation
protection of the bare gold electrode for long life, stability, and precision accuracy in extremely challenging
waters. The FR-300-PLUS is also designed to be utilized with a wide variety of alternative Pyxis inline sensors for
a broad range of measurement. These additional sensors are outline in this document.
The FR-300-PLUS contains a ‘chemical injection port’ in the assembly housing allowing for the optional injection
of cleaning agents at the brush head for extremely challenged industrial waters containing fats, oils and grease.
This port may also be used for the addition of Potassium Iodide for measurement of “True Total Chlorine”. The
FR-300-PLUS may be operated at a broad range of regulated sample flow from 200 and 800mL per minute with
an inlet pressure of <30 psi. The FR-300-PLUS outlet flow line should be diverted to drain or returned to an
atmospheric tank/sump within the process itself for reuse.
The FR-300-PLUS comes equipped with a magnetically coupled brush mounted in the liquid end of the flow
reservoir. Operational life of the brush is typically 1+ year of service however this is application dependent based
on water quality. The brush is held in place via magnetic coupling to the motor shaft for rapid tool-free removal
and replacement. Brush replacement is outlined in the later sections of this document.
The FR-300-PLUS requires 24VDC power supply at approximately 2.5watts and can be directly connected to the
OEM controller or may be powered by the optional Pyxis Lab outlet power supply adapter accessories available
for both 110VAC and 230VAC outlet operation. (Purchased separately)
Pyxis Lab has developed a wide variety of pre-assembled analyzer panels incorporating the proprietary ST-765SS
series sensor in combination with FR-300-PLUS self-brushing flow assembly and the UC-Series of Pyxis display
and data logging terminals. Alternatively, the ST-765SS Series sensors and FR-300-PLUS self-brushing flow
assembly may be utilized with OEM controllers, PLC’s and DCS networks to providing a higher level of control for
system chemistry applications while incorporating the unique Pyxis bare-gold sensor technology.

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FR-300-01 Replacement Brushing Assembly Dimensions (mm) & Image
FR-300-01 Replacement Brushing Assembly Replacement Procedure

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FR-300-PLUS Installation & Operation Guidelines
Mounting: The FR-300-PLUS must be securely mounted to a back panel through the three (3) pre-drilled screw
mounting holes in the reservoir body, with the Pyxis sensor aligned in a horizontal format as seen in the figure below.
*NOTE* Sensor may be aligned to the left or right as desired.
Controller/PLC Provided Power Supply & Operation Mode: The FR-300-PLUS is a stand-alone unit and requires
24VDC power supply to operate. Operating 100% of the time is the Pyxis suggested form of operation of the FR-300-
PLUS, however some clients may desire to operate on a timed cycle or flow condition basis on desired cleanliness and
system operation. This can be done via the connected controller as a powered relay activating the FR-300-PLUS on a
timed sequence or system flow switch relay. See wiring section for FR-300-PLUS wiring.
Outlet Provided Power Supply &Operation Mode: For applications that require outlet provided power supply to the
FR-300-PLUS, Pyxis offers MA-AC-7US (P/N 26398) and MA-AC-7EU (P/N 28787) power supply adapters in both
110VAC-USA (Type B) and 230VAC-EU (Type DIN) formats as optional accessories. These accessories allow the FR-300-
PLUS to be outlet powered and operational 100% of the time. See order information section of this document for
details.
RS-485 Communication: The FR-300-PLUS offers RS-485 connectivity which allows for rotational brush speed,
operation and duration for those desiring precision control. Full time operation is suggested by Pyxis Lab for optimum
sensor cleanliness.
Inlet/Outlet Flow: When mounted horizontally the inlet water flow to the FR-300-PLUS should enter the bottom of
the unit via inlet port (3/8-inch OD) as seen in image above. The outlet water flow should exit the top of the unit via
the outlet port (3/8-inch OD). The inlet water pressure should not exceed 30 psi. The outlet water should be returned
to open sump at atmospheric pressure. The range of flow through the FR-300-PLUS should be consistently regulated
between 200 and 800mL/minute. An inlet rotameter may be installed to verify and regulate inlet flow however, this is
not absolutely necessary and a manual flow verification test is sufficient as long as flow remains consistently regulated.
*NOTE* The FR-300-PLUS should be installed in a way to ensure the ST-765 series sensor remains flooded and wet
regardless of flow condition.
Calibration: Once flow has been established and regulated, an in-situ slope calibration of the sensor can should be
conducted using field analysis of the sample being measured. (i.e. DPD Free Chlorine) See ST-765SS Series Operation
Manual for detailed calibration instructions.

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OxiPanel IK-765SS-Br (Bromine + pH + Temperature Online Monitoring Panel)
For customers desiring a “Turn-Key” analyzer, the IK-765SS-Br is a pre-assembled Bromine + pH + Temperature
monitoring panel. The IK-765SS series offers highly accurate, real-time measurement, display and data-logging
of Bromine, pH and Temperature utilizing proprietary Pyxis Lab smart sensor technology, coupled with a Pyxis
UC-50 micro display and data logging terminal. The IK-765-B also incorporates the uniquely designed FR-300-
PLUS automated mechanical brush flow assembly which is directly controlled via the UC-50 display to maintain
optimum sensor electrode cleanliness in the most challenging of system water.
The UC-50 is a microprocessor display/data-logging terminal that has been preconfigured to connect Pyxis
inline sensors with fully integrated calibration, scaling and measurement protocol. The user may also
configure and calibrate the output signal through the UC-50 controller's screen.
Image and Dimensions of IK-765SS Series (mm)
Figure 3 – IK-765SS-Br Series Panel
Item
P/N
Description
IK-765SS-Br-B 44074
ST-765SS-Br Sensor + FR-300 PLUS Flow Reservoir
+ UC-50 Display/Data Logger

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4. Wiring ofST-765SS-Br Sensor & FR-300-PLUS Flow Reservoir
ST-765SS-BrWiring Instructions
Follow the wiring table below to connect the ST-765SS-Brsensor to a controller or PLC. *NOTE* All Pyxis sensors
provide a passive 4-20mA output signal, they are NOT LOOP POWERED. 24VDC+ power supply and 4- 20mA+
signal are independent of each other in all Pyxis Lab sensors. If the 24V power ground and the 4-20 mA-return
in the controller are internally connected (non- isolated 4-20mA input), it is unnecessary to connect the 4-20 mA-
(Gray wire) to the 4-20 mA negative terminal in the controller.
Wire Color Designation
Red 24 V +
Brown Power Ground
Green Shield, solution ground
Gray 4-20 mA -
White 4-20 mA + for Bromine
Pink 4-20 mA + for pH
Blue RS-485 A
Yellow RS-485 B
Black Shield, solution ground
ST-765SS-Br Sensor 4-20mA Scaling
Unit of Measure 4mA Value 20mA Value
pH 0.00 pH 14.00 pH
Bromine 0.00 ppm 5.00 ppm
FR-300-PLUS Wiring Instructions
Follow the wiring table below to connect the FR-300-PLUS to a controller or the Pyxis UC-50 via 24VDC and
RS-485 Modbus. Alternatively, any OEM controllers capable of providing 24VDC power supply may also be
used. The FR-300-PLUS may be operated 100% of the time with no issue, simply by providing the unit 24VDC
power supply. Some users may also consider operating the FR-300-PLUS as desired in an ON/OFF relay
format based on their application needs. NOTE – The FR-300-PLUS may be operated via 110VAC or 230VAC
outlet power supply by utilizing optional Pyxis power supply adapter cables with plug purchased separately.
See the ORDER DETAILS section of this document for details.
Pin # Wire Color Designation
1 Red 24V
2 Black 0V
3 Blue 485A
5 Yellow 485B
7 Silver Ground
4 White NA
6 Green NA
*NOTE* Pyxis recommends the 24VDC power supply to the ST-765 series sensor be turned OFF for systems that
experience extended periods of stagnant water conditions exceeding one hour in duration.

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5. Calibration and Diagnosis
The ST-765SS Series sensors are rigorously calibrated before leaving the factory. As such, users do not need
to calibrate the sensor for a period of three months or up to one year if the sensor is maintained in clean
condition. Users can however calibrate the sensor according to their application needs and as desired using
the MA-CR Bluetooth adapter and uPyxis APP for mobile or desktop devices.
4.1 Calibration and Diagnosis by uPyxis Mobile App
Connect and power the ST-765SS sensor using the MA-CR Pyxis Bluetooth adapter (P/N: MA-CR) as shown
in the following connection diagram. The power should be sourced from a 24 VDC power terminal of a
controller. If a controller is not available, please purchase a 24VDC power supply.
Figure 4. –
Power the ST-765SS via Display or Controller with the MA-CR Bluetooth Adapter inserted between Bulkhead & Flying Lead Cables
8- Pin Sensor
Controller or Display uPyxis Mobile app
8-Pin Sensor
MA-CR Bluetooth Adapter

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Download and install the uPyxis app from Apple Store or Google Play. Turn on the
Bluetooth in the smart device (please do not pair your device Bluetooth to uPyxis,
the app will do the pairing). Open the uPyxis app in the device. Swipe down with
finger to refresh the screen to scan the available Pyxis Bluetooth devices. The
discovered devices will be listed as shown in Figure 5.
Tap the discovered ST-765SS sensor to connect to the sensor. The uPyxis app can
identify the sensor type if multiple Pyxis sensors are discovered in the scan.
As shown in Figure 6, in the calibration page of uPyxis after connected to the sensor via the MA-CR
Bluetooth adapter the current Bromine, pH and temperature values will be displayed. Six functional tabs of
each are available in this page: Zero Calibration, Slope Calibration, pH Low Calibration, pH 7 Calibration, pH High
calibration and 4-20mA Span.
Figure 5 - ST-765SS Discovered via Bluetooth Figure 6 - Calibration Page
4.1.1 Bromine Calibration
The oxidizer measurement module of ST-765SS Series is rigorously calibrated before leaving the factory. If
calibration is required, users can perform single-point or two-point calibration as required. Calibration for
Zero and Slope Calibration using a known standard and actively flowing sample that has been tested and
measured by DPD wet chemistry method is recommended.

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4.1.1.1 Single Point Calibration Procedure
The ST-765SS Series must be slope calibrated in the FR-300-PLUS flow reservoir provided with the sensor and
must have CONSISTENT flow within the specified range of 200 to 800mL per minute. Determine the Bromine
concentration in ppm of the sample water taken from the FR-300-PLUS output sample by using the DPD
method on a portable or laboratory colorimeter (i.e.. Pyxis SP-200 / SP-800 / SP-910 or similar). Launch the
uPyxis app and connect to the ST-765SS Series sensor. Tap SLOPE CALIBRATION. Enter the Bromine
concentration determined by the DPD method in the dialog window as shown in Figure 7. Please make sure
that the sensor reading has been stable for at least 10 minutes before calibration. For best results, the
concentration of the bromine sample flow standard should be in the range of 0.1 to 5.0 ppm.
4.1.1.2 Two-Point Calibration Procedure
Zero-point Calibration: Launch the uPyxis app and connect to the ST-765SS sensor. Remove the ST-765SS
sensor from the FR-300 flow reservoir and place the sensor into a beaker containing Pyxis Zero-oxidizer
Calibration Standard Solution (P/N 21022), then tap ZERO CALIBRATION in the uPyxis app. Please allow
sufficient time (a few minutes) for the sensor to stabilize before performing the calibration. *NOTE* Users
may also use up to 100 us/cm conductivity standard as a ZERO CALIBRATION solution.
Slope-point Calibration: Insert the ST-765SS Series sensor back into the FR-300-PLUS flow reservoir and
reestablish sample flow. The ST-765SS Series must be slope calibrated in the FR-300-PLUS flow reservoir
provided with the sensor and must have CONSISTENT flow within the specified range of 200 to 800mL per
minute. Determine the Bromine concentration in ppm of the sample water taken from the FR-300-PLUS
output sample by using the DPD method on a portable or laboratory colorimeter (i.e.. Pyxis SP-200 / SP-800
/ SP-910 or similar). Launch the uPyxis app and connect to the ST-765SS Series sensor. Tap SLOPE
CALIBRATION. Enter the bromine concentration determined by the DPD method in the dialog window as
shown in Figure 7. Please make sure that the sensor reading has been stable for at least 10 minutes before
calibration. For best results, the concentration of the bromine sample flow standard should be in the range
of 0.1 to 5.0 ppm.
Figure 7 - Enter Test Confirmed Bromine Concentration to begin Slope Calibration

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4.1.2 pH Calibration
Remove and place the sensor in a low pH (i.e.. 4.0) calibration standard solution and tap pH LOW
CALIBRATION in the uPyxis app. Measure for 1 minute and wait for the measurement result to stabilize before
performing calibration, the low pH calibration standard value range acceptable for this step is 1.00-6.00 pH.
Place the sensor into the pH 7.0 calibration standard solution and tap pH 7 CALIBRATION in the uPyxis app.
Measure for 1 minute and wait for the measurement result to stabilize before performing calibration.
Place the sensor in a high pH (i.e. 10.0) calibration standard solution and tap pH HIGH CALIBRATION in the
uPyxis app. Measure for 1 minute and wait for the measurement result to stabilize before performing
calibration, the high pH calibration standard value range acceptable for this step is 8.00-13.00 pH.
Figure 8 Figure 9
Enter Low-pH Concentration for Calibration Enter High-pH Concentration for Calibration

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4.1.3 4-20mA Span
The 4–20mA output of the ST-765SS-Br sensor is scaled as:
•Bromine:
– 4 mA = 0 ppm
– 20 mA = 5 ppm
Tap 4-20mA SPAN to change the bromine value corresponding to the 20mA output to a lower value as seen
in Figure 10. *NOTE* The 4-20mA Span feature allows users to REDUCE the upper 20mA output scale only.
You cannot INCREASE the upper limit of the sensor beyond the range of the sensor.
Figure 10 – Adjust 20mA Setting for Bromine (<5ppm)
Figure 11 - Diagnostic Interface
4.1.4 Diagnosis
Tap Diagnosis in the bottom of the app page to launch the diagnosis page Figure 11.
In this page, the raw data measured by the sensor is displayed. To help troubleshooting possible issues with
the sensor, please save images of these data when the sensor is respectively placed in a clean water (tap
water or deionized water), in a pH standard solution, and in the sample that the sensor is intended for. This
data may be exported from the uPyxis APP via email to [e-mail] for technical support.

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4.2 Calibration and Diagnosis by uPyxis Desktop App
1) Download and install uPyxis Desktop APP from
https://upyxis.pyxis-lab.com.cn/release/pc/uPyxis.Setup-latest.zip
2) Connect a USB Type-C cable to the port at the bottom of the MA-CR and to the USB port of the laptop or
computer. This will provide power the MA-CR from the laptop/computer. Connect the MA-CR to the ST-765SS-
Br sensor. The MA-CR Bluetooth adapter will boost the 5V of the regular USB to 24V to power the sensor for
use with uPyxis Desktop.
Figure 12 – MA-CR Connected to Sensor & Laptop
3) Set the MA-CR to operate in USB Mode by following the steps below.
a. Once the MA-CR screen is powered Press or until you arrive at (USB to RS485)
screen.
b. Press the Button.
c. Follow Prompts below to Enable USB feature. Once enabled, you may connect to uPyxis.
MA-CR Bluetooth Adapter – Bottom USB-C

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4) Open the desktop uPyxis APP.
5) Click Device to launch the connection option menu.
6) Select Connect via USB-RS485 (Figure 13).
7) Select the Comm Port to make a connection. Normally only one Comm port is identified by
uPyxis (Figure 14). If more than one Comm port listed in the selection dropdown, you may try
to select each one to see if a connection can be made. Alternatively, you may use the
Windows Device Manager to identify the Comm Port that the Pyxis USB adapter is using.
After the connection is established, the ST-765SS sensor series number and Bromine reading will be displayed
on the left of the information page Figure 15. In this page, a nickname can be assigned to the sensor. The
sensor Modbus address can also be changed if desired. Click Calibration to launch the calibration page Figure
16.
Figure 13 - Connection Options