Interscan Corporation ACCUSAFE F901B User manual

Interscan Corporation.
Instruction Manual
ACCUSAFESensorModule

Accusafe Sensor Module User Manual 1 06/21/2021
Table of Contents
Section 1 - Introduction...................................................................................................................................... 2
1.1 Important Safeguards .............................................................................................................................. 2
1.2 Accusafe F901B Sensor Specifications..................................................................................................... 3
1.2.1 Sensor MODULE Configuration......................................................................................................... 3
Section 2 - Installation ........................................................................................................................................ 4
2.1 Enclosure Wall Mounting......................................................................................................................... 4
2.2 Wiring and Pneumatic Connections ........................................................................................................ 4
2.1.1 Power and MODBUS connections .................................................................................................... 4
2.1.2 Pneumatic connections..................................................................................................................... 5
Section 3 - Operation.......................................................................................................................................... 7
3.1 Pump & Sensor Operation....................................................................................................................... 7
3.2 MODBUS Operation................................................................................................................................. 7
3.2.1 RTU RS485 Configuration.................................................................................................................. 8
3.2.2 F-901B MODBUS Specifications........................................................................................................ 9
3.2.3 Input Registers.................................................................................................................................. 9
3.2.4 Holding Registers ............................................................................................................................ 10
3.2.5 Coils................................................................................................................................................. 10
Section 4 - Calibration....................................................................................................................................... 12
4.1 Zero Calibration ..................................................................................................................................... 12
4.1.1 Zero Calibration Procedure............................................................................................................. 13
4.2 Span Calibration..................................................................................................................................... 15
4.2.1 Gas Calibration Procedure......................................................................................................... 15
4.2.2 Digital Calibration Procedure.......................................................................................................... 18
Section 5 - Maintenance of the F-901B............................................................................................................ 20
5.1 Replacing the Gas Sensor....................................................................................................................... 20
5.2 Particulate Filter Maintenance .............................................................................................................. 21
Section 6 –Sensor Module Tester App............................................................................................................. 22
Section 7 - Warranty......................................................................................................................................... 25

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Section 1 - Introduction
To reduce the risk of fire, electrical shock, injury to persons or permanent damage to this device,
these safety precautions should always be followed:
•Use the included 12VDC power supply or specified power connector to operate this device.
Inappropriate voltage supply or power connector could cause irreparable damage to this
device.
•Make sure power plug and Modbus cable are plugged in and secured before powering up the
device. The power connector will not make connection to GND if not fully plugged into the
socket. Also make sure the locking ring is securely tightened.
•If sampling via tubing, make sure that the tubes are securely attached to the device before
operating. Use the provided particulate filter to prevent dust and particulates from entering the
device. See section 2.1.2, pg. 5.
•Do not operate the device with an obstructed flow path. Obstruction during air sampling will
damage the internal micropump. See section 5.2, pg. 21.
•Do not expose this device to any liquids.
•Sensors must not be exposed to temperature, humidity and pressure that are outside the
operating range. See section 1.2, pg. 3.
1.1 IMPORTANT SAFEGUARDS

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Measurements
Target Gas, RH, Temperature, Barometric
Pressure
Air Sampling Rate
60-160 mL/min (Pump speed 50% - 100%)
Measuring Rate
Continuous
Communication
Modbus via RTU/RS485 & TCP/IP
Sampling Port
Inlet/outlet with Luer lock fittings
Operating environment
0°C - 50°C, 15-90% relative humidity non-
condensing
Power Input
12VDC regulated
Avg. Power Consumption
2.5W
Dimensions
8 in x 4.7 in x 2.2 in (includes mounting flanges)
Weight
0.98kg
Enclosure
Powder-coated aluminum
Gas Sensor
Type
3 electrode electrochemical
Nominal Range
See section 1.2.1 below
Accuracy
± 2% of reading ± least significant digit
Lower Detection Limit
2 ppm
Response Time (T90)
< 3 minutes (varies by gas type)
Temperature Range
-20 °C to 50 °C (varies by gas type)
Pressure Range
atmospheric ± 10 %
Relative Humidity Range
15 % to 90 % R.H. non-condensing
Long Term Output Drift
< 2 - 5 % per month in continuous exposure
(varies by gas type).
Lifetime
2 –3 years (varies by gas type)
1.2.1 SENSOR MODULE CONFIGURATION
This section details the specific gas and range parameters for your ACCUSAFE instrument.
GAS –
SENSOR RANGE –
1.2 ACCUSAFE F901B SENSOR SPECIFICATIONS

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Section 2 - Installation
The sensor module is wall mountable using M5 or #10 screws. Install the module in the immediate
area from which you want to draw sample. Consideration should be givento the whether thetarget
gas is heavier or lighter than air in choosing the height of the installation location. Allow for 18”
total horizontal space to accommodate pneumatic and cabling connections to the sides of
the enclosure.
2.1.1 POWER AND MODBUS CONNECTIONS
Connect the 12V power adapter to the sensor module by inserting the plug into the 12V power
receptacle and tightening the lock ring snugly.
For TCP/IP communications applications, connect a standard CAT5 communications cable to the
MODBUS communications port. This cable will connect to the “ETHERNET” port on the
ACCUSAFE controller module for non-web browser single sensor applications or to an Ethernet
switch or hub for single or multi-sensor applications that utilize the web browser application.
For RTU (RS485) communications applications, connect a standard CAT5 communications cable
to the MODBUS communications port. This cable will connect to the “RS485” port on the
ACCUSAFE controller module for single sensor applications or to the next sensor in the daisy
chain for multi-sensor applications**.
**NOTE: Multi-sensor applications using RS485 connections will require a splitter device be used
at each node in the chain using a multi-drop (daisy chain) topology.
2.1 ENCLOSURE WALL MOUNTING
2.2WIRING AND PNEUMATIC CONNECTIONS
12V Power Receptacle
LED
ModBus Communication Port
Gas Inlet
Gas Outlet
Mounting Holes*
7
.
*accepts M5 or #10 screw
4
7
.
3.14 in
7
.
4
0
”
7.40 in

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NOTE: Waterproof cap for CAT5 cabling shown below (not provided with sensor) can be acquired
as needed at this link: https://www.installerparts.com/16279-patch-cable-waterproof-cap.html
2.1.2 PNEUMATIC CONNECTIONS
A particulate filter (pictured on the right) is provided for
connection to the inlet of the sensor module. This filter
protects the sensor and internal components from dust
and particulates that may be present in the sample.
To connect this filter, slip the end of the filter fitting into
the opening of the inlet fitting and rotate the filter in a
clockwise direction. Tighten snugly but do not over
tighten.
Connect exhaust tubing (1/8” I.D.) as needed by
inserting the provided barbed adapter fitting
connected to tubing into the OUTLET fitting as shown
on the right. Turn the fitting in a clockwise direction
until snugly tightened. Do not over tighten.
RJ45 Male Plug*
Waterproof Cap
ROTATE

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IMPORTANT:
•MAKE SURE POWER CABLE AND MODBUS CABLE ARE SECURED BEFORE POWERING
UP DEVICE.
•MAKE SURE THERE IS NO FLOW OBSTRUCTION AT INLET/OUTLET BEFORE POWERING
UP DEVICE.
•PARTICULATE FILTER SHOULD BE CHECKED PERIODICALLY AND REPLACED AS
NEEDED ACCORDING TO SECTION 5 OF THIS MANUAL.

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Section 3 - Operation
The ACCUSAFE F901B Sensor Module is designed for continuous operation when paired with
the ACCUSAFE Controller Module (see dedicated controller manual for operation of the
controller).
As soon as the F901B Sensor Module is powered up and the firmware is fully booted, the pump
will run continuously, drawing sample air past the sensor. The sensor’s output signal is
communicated via MODBUS to the controller which then displays this signal in graphical and
numeric forms.
The pump’s speed can be controlled at the controller if more or less flow rate is desired (factory
set nominal pumpspeed is 50%). This functionality is described in greater detail in the ACCUSAFE
Controller Module manual.
The F901B supports the standard Modbus protocol in both RTU and TCP/IP modes. The 3
available operation modes are detailed below. (see MODBUS MODE in table 3-4, pg. 10 for
Modbus mode register addressing information). AUTO MODE is the recommended mode and is
factory set prior to shipment:
•AUTO Mode (factory preset mode) - In this mode, if the sensor detects a connection to an
active Ethernet device, it will initialize Modbus TCP/IP protocol via the default static IP address
192.168.1.XX port 502 (The suffix of this address will be indicated on a label next to theEthernet
port. Address is configurable via Modbus commands where necessary. See SLAVE ADDR in
Table 3-4, pg. 10). If not connected to an Ethernet connection, it will initialize in RTU mode.
•Fixed TCP/IP mode - Upon powering up, the F901B always initializes the Modbus TCP/IP
protocol via the default static IP address 192.168.1.XX port 502 (The suffix of this address will
be indicated on a label next to the Ethernet port. Address is configurable via Modbus commands
where necessary. See SLAVE ADDR in Table 3-4, pg. 10).
•Fixed RTU mode - Upon powering up, the F901B always initializes the Modbus RTU protocol
via the default static IP address 192.168.1.XX port 502 (The suffix of this address will be
indicated on a label next to the Ethernet port. Address is configurable via Modbus commands
where necessary. See SLAVE ADDR in Table 3-4, pg. 10).
NOTE: The F901B sensor’s internal communications cabling is configured to operate in TCP/IP
mode. If operating in RTU mode is desired, the internal communications cabling will need to be
swapped. Contact the INTERSCAN SERVICE DEPT. for more information on making this
change.
3.1 PUMP & SENSOR OPERATION
3.2 MODBUS OPERATION

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3.2.1 RTU RS485 CONFIGURATION
RS485 cabling configuration is shown in the diagrams and table 3-1 below.
Pin
Name
Type
Description
1
3.3V
Reference potential
3.3V Reference Voltage
2
GND
Reference potential
Local device ground
3
UART_TX
Digital Output
Firmware update interface
4
B (D-)
Bus In/Out
Driver output and receiver input
5
A (D+)
Bus In/Out
Driver output and receiver input
6
UART_RX
Digital Input
Firmware update interface
7
BOOT
Digital Input
Firmware update interface
8
RESET
Digital Input
Microcontroller reset input (Active-Low)
Firmware update interface
TABLE 3-1
IMPORTANT: use pin 4,5 (B/A) and GND for Modbus RS485 communication. Pin 3,6,7,8 are
reserved for firmware updating and are 3.3V tolerant.
Absolute Maximum Rating
Voltage range at A or B ………………………………………………. -8V to 12V
Voltage range at pin 3,6,7,8 ……………………………………….. -0.3V to 4V
Electrostatic discharge at A and B ………………………………. ±8kV
RS485 Modbus Parameters
Parameter
Value
Default
address
50
Baud Rate
19200
Data bits
8
Parity
Even
Stop bits
1
TABLE 3-2
Bottom
View

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3.2.2 F-901B MODBUS SPECIFICATIONS
•Operates as a slave, half-duplex mode
•Modbus functions supported:
o0x01 - Read Coils
o0x03 - Read Holding Registers
o0x04 - Read Input Registers
o0x05 - Write Single Coil
o0x06 - Write Single Register
o0x0F - Write Multiple Coils
o0x10 - Write Multiple Registers
•Exception messages supported
•Default address:
oRTU: 50
oTCP/IP: 192.168.1.50
3.2.3 INPUT REGISTERS
Mode: Read-only, size: 16 bits
Name
Address
Description
SENSOR OUTPUT
0
Gas measurement x 10, ppm
TEMPERATURE
3
Temperature measurement x 10, C (Note: 16bit
signed number)
RELATIVE HUMIDITY
4
Relative Humidity measurement x 10, %
BAROMETER
5
Barometric pressure measurement x 10, mbar
VAPOR PRESSURE
6
Vapor pressure of water measurement x 10, mbar
ERROR STATUS
9
0 = OK.
1 = C2H4 offset error, Sensor over-exposed or
KMnO4 filter needs to be replaced.
SENSOR_RAW_VALUE
10
C2H4 raw measurement, count
DEV_TYPE
100
Default device type ID: 9011
FIRMWARE
101
Firmware version
TABLE 3-3
NOTE:
•Above addresses are offsets. The function address for input register is [30001 + offset]
•Temperature and Humidity are measured at the sensor’s inlet and may not represent room
condition or remote/localized spots. External temperature probe provided in F901B v2 sensor.

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3.2.4 HOLDING REGISTERS
Mode: Read/Write, size: 16 bits (unsigned)
Name
Address
Default
Description
PUMP_POWER
0
50
Internal pump power 0-100%
SENSOR_SPAN
1
NONE
Sensor span calibration parameter. Calibration formula:
SENS_SPAN=SENS_CUR*SENS_SPAN_CUR/SENS_CAL
Note: SENS_CAL: expected calibration concentration
SENS_SPAN_CUR: Current span value
SENS_CUR: Current SENSOR measurement
SENSOR_ZERO
2
NONE
SENSOR zero calibration parameter
SLAVE_ADDR
30
50
Device Modbus RTU slave address. Update this
register to change the slave address. Valid slave
addresses: 0-99
MODBUS_MODE
31
0
0: TCP/IP (LED blinks 2 times at boot)
1: RTU (LED blinks 3 times at boot)
2: Auto Config Mode. (Factory Default) During boot up,
if the internal TCP/IP cable is plugged in and the device
is connected to active ethernet hub/router or the F901C
Controller, the device will select TCP/IP mode.
Otherwise, RTU mode is selected.
IP_ADDR0
32
192
Device local IP address
IP_ADDR1
33
168
Device local IP address
IP_ADDR2
34
1
Device local IP address
IP_ADDR3
35
50
Device local IP address
TABLE 3-4
NOTE:
•Above register addresses are offsets. The function addressfor holding register is [40001 + offset]
•Values written to the above holding registers remain after Power-off/Reset
IMPORTANT:
•Changing the pump power to different value than the factory default may affect measurement
accuracy. In such case, a complete sensor re-calibration is recommended.
•Backup calibration parameters before overwriting their values (performing a calibration) or
update device firmware(all parameters will be erased). All F-901B comes with factory calibration
using standard certified gases.
3.2.5 COILS
Mode: Read/Write, size: 1 bit
Name
Address
Default
Description
CONF
7
False
Confirmation of zero action
RESET
9
False
True: (software) reset
False: no action
Note:
•Above addresses are offsets. The function address for coil is [00001 + offset]

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IMPORTANT:backup calibration parameters before performing a calibration. A calibration will
overwrite the factory calibration parameter in the Holding register.

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Section 4 - Calibration
All units are shipped factory‐calibrated. Over time all sensors require recalibration to compensate
for natural sensor sensitivity loss. The performance of a sensor or the whole instrument should be
checked occasionally with calibration gas. When there is significant accuracy error in response,
calibration may be indicated.
NOTE: Because environmental conditions may differ between factory calibration and installation,
it is a good idea to challenge the sensor with a known concentration of gas upon installation to
confirm the calibration integrity following shipping. Re-calibration may be indicated if reading error
is significant.
Calibration frequency depends on a number of factors including application, environmental
conditions, local regulations and accuracy requirements. Calibrating every quarter is a good
starting point. If significant scaling adjustment is required during calibration using this interval,
more frequent calibration is indicated.
There are several options for calibration:
•You can ship your F-901B sensor module back to Interscan Corp. for calibration.
•You can order pre-calibrated sensors from Interscan for replacement of the existing sensor and
perform Digital Calibration after installation (See section 4.2.2, pg.18)
•You can calibrate the sensors yourself (Gas Calibration –See section 4.2.1, pg. 15).
NOTE 1: If performing calibration yourself, replace the sensor when its sensitivity (span) is
below 50 % of its initial value. Initial SPAN value can be determined from the “Sens Span” value
on the SENS DATA Panel in the Control Panels Menu of the Controller. See section 3.1.2, Figure
3-4 of the Controller Module User Manual for details on accessing this parameter.
NOTE 3: Calibration procedures will entail making numeric entries
on the pop-up screen shown to the right. The current value is shown
at the top of the window. Always clear this value first by touching the
C button (red arrow shown on right) before entering a new value.
Use the BACKSPACE button (green arrow shown on right) to erase
individual digits and use the ENTER button (yellow arrow shown on
right) to save the entered value.
Zero calibration should be performed periodically to compensate for natural temperature drift in
the gas sensor. Zeroing should also be performed upon initial start-up and prior to every SPAN
calibration. In applications where temperature swings are significant, daily zeroing may be
indicated.
4.1 ZERO CALIBRATION

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In most cases clean ambient air can be used for
zeroing as long as it is known to be free of any
interference gases. Some interferences can be
eliminated with the use of the provided charcoal
scrubber filter shown to the right. This filter attaches
to the inlet filter as shown.
O2can also be used as a zero gas where clean
ambient air is not available and charcoal scrubbing
is not effective. DO NOT USE NITROGEN AS A
ZERO GAS FOR THE ACCUSAFE SYSTEM.
If using a pressurized gas bottle and pressure-controlled regulator for O2zeroing, follow the setup
below to properly apply the gas at the sensor’s INLET fitting (limit pressure to 4 PSI or lower).
If using an On-demand type regulator, the T junction fitting can be omitted.
4.1.1 ZERO CALIBRATION PROCEDURE
1) Open the CALIBRATION screen on the Controller Module by touching the CALIBRATION
icon on the main toolbar as shown below.
2) Select the ZERO radio button as shown by the arrow below.
Excess Gas
INLET
T JUNCTION
PRESSURE REGULATOR

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3) Enter the correct Sensor Slave Address by touching the entry field (circled in the image
above) and entering the address number on the pop-up entry screen.
-For TCP/IP applications, the slave address will be 192.168.1.XX (substitute the Sensor
module’s modbus address for “XX”).
-For RTU applications, the slave address will only be the 2 digit modbus address. Be sure
to check that the address is correct before continuing.
4) Enter the Calibration Duration time in minutes by touching the entry field circled below and
entering the number on the pop-up entry screen. Typically 2-3 minutes is adequate for most
applications.
5) Tick or untick the Pump On During Calibration checkbox (red arrow above) for your
application. PUMP ON will be the correct selection in most applications. Consult with the
INTERSCAN Service Dept. for guidance if unsure.
6) Connect the zero air sample source to the inlet of the F901B sensor as shown on the previous
page.
7) Touch the “NEXT STEP” button to advance.
8) Wait while the Zero calibration timer elapses as indicated by the green timeline bar. Press
“ABORT” to cancel the calibration if desired.

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9) When the calibration timer has elapsed, a “Calibration Completed” window will be displayed
as shown below. Press “OK” to accept then press “EXIT” to return to the main SENSOR
CALIBRATION screen.
10)If finished with calibration, select the desired screen from the main toolbar.
SPAN Calibration compensates for sensitivity loss in the gas sensor. The instrument can be
calibrated in one of two ways:
Gas Calibration - A known concentration of gas is introduced and the sensor is allowed to
respond over the calibration sampling period. The calibration scaling is automatically updated at
the end of this sampling period.
The sources of gas standards include commercially available gas mixtures diluted with air in
cylinders or permeation devices. NOTE: Gas blends in a balance of nitrogen should not be
used with the Accusafe sensors.
Digital Calibration –A pre-calibrated sensor is provided by Interscan to replace the old sensor.
The new sensor is accompanied by a calibration certificate that includes a sensitivity value to be
entered during the Digital calibration procedure.
4.2.1 GAS CALIBRATION PROCEDURE
1) Open the CALIBRATION screen on the Controller Module by touching the CALIBRATION
icon on the main toolbar as shown below.
2) Select the Gas Calibration radio button as shown by the arrow below.
4.2 SPAN CALIBRATION

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3) Enter the correct Sensor Slave Address by touching the entry field (circled in the image
below) and entering the address number on the pop-up entry screen.
-For TCP/IP applications, the slave address will be 192.168.1.XX (substitute the Sensor
module’s modbus address for “XX”).
-For RTU applications, the slave address will only be the 2 digit modbus address. Be sure
to check that the address is correct before continuing.
4) Enter the Calibration Duration time in minutes by touching the entry field circled below in
red and entering the number on the pop-up entry screen. Typically 5 minutes is adequate for
most applications.
5) Enter the Calibration Concentration [PPM] value by touching the entry field circled above
in green and entering the number on the pop-up entry screen. This is the value of the CAL
GAS concentration being used for calibration.
NOTE: If the cal gas being used is measured in PPB units, be sure to convert its value
to PPM for this entry –i.e. if the Cal Gas is specified as 500 PPB, the entry would be
0.5 PPM.

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6) Leave the Calibration in Trigger Mode box indicated by the red arrow above UNTICKED.
This option will not apply to most Accusafe applications.
7) Touch the “Next Step” button to advance the cal routine.
8) Connect the CAL GAS supply to the inlet of the sensor module as indicated on the screen
shown below. Touch the “NEXT STEP” button when ready. Touching the “RESET” button will
cancel the calibration.
NOTE: When using CAL GAS from a pressurized source, be sure to include an “on demand”
regulator at the source OR a tee fitting between the source and inlet as shown below. (limit
pressure to 4 PSI or lower).
9) Wait while the Span calibration timer elapses as indicated by the green timeline bar. During
this time, the gas sensor will respond to the Cal Gas as indicated by the green “Sensor
Measurement” value. The screen also displays the Calibration Concentration, the previous
span value, and the new updated span value (shown after cal is completed). Press “ABORT”
to cancel the calibration if desired.
Excess Gas
INLET
T JUNCTION
PRESSURE REGULATOR

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10)Once the calibration timer elapses and the verification process is complete, a new window
will display “Calibration Completed”. Click OK to accept the calibration and EXIT to return
to the main sensor calibration screen.
4.2.2 DIGITAL CALIBRATION PROCEDURE
1) Replace the existing sensor with the pre-calibrated sensor provided by Interscan Corp. (See
section 5-1, pg. 20 for directions on replacing the sensor). With power applied to the sensor
module, allow 24 hours for the new sensor to stabilize before calibrating.
2) Perform a ZERO calibration according to section 4.1.1, pg. 13.
3) Open the CALIBRATION screen on the Controller Module by touching the CALIBRATION icon
on the main toolbar as shown below.
4) Select the Digital Calibration radio button as shown below (red arrow)

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5) Enter the correct Sensor Slave Address by touching the entry field (circled in red in the image
above) and entering the address number on the pop-up entry screen.
-For TCP/IP applications, the slave address will be 192.168.1.XX (substitute the Sensor
module’s modbus address for “XX”).
-For RTU applications, the slave address will only be the 2 digit modbus address. Be sure
to check that the address is correct before continuing.
6) Enter the Sensor Sensitivity (nA/PPM) value as indicated on the calibration certificate that
accompanied the sensor. Touch the field shown above circled in green and enter this value
on the pop-up entry screen. Be sure this value is correct before proceeding. Touch the NEXT
STEP button when satisfied with your entry.
7) The confirmation screenshown below will now bedisplayed indicating that the sensitivity value
was set. Touch the OK button to confirm then touch the EXIT button to complete the
calibration.