PureAire TX-KE User manual

PureAire Monitoring Systems, Inc. 2/22/2000
0
Models TX-KE and TX-KP
Toxic Gas Transmitters
Instruction Manual
PureAire Monitoring Systems, Inc.
557 Capital Dr.
Lake Zurich, IL. 60047
Phone: [phone]
Fax: [phone]
Toll-Free: 888-788-8050
www.pureairemonitoring.com

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Table of Contents
1: Introduction ................................................................................................. 2
1.1 Model TX-KE........................................................................................ 2
1.2 Model TX-KP........................................................................................ 2
2: Specifications ............................................................................................... 5
2.1 Performance Specifications.................................................................... 5
2.2 Signal Outputs ....................................................................................... 5
2.3 Electrical Requirements ......................................................................... 5
3: Installation ................................................................................................... 6
3.1 Wiring ................................................................................................... 6
3.2 Sensor Installation.................................................................................. 9
4: Normal Operation...................................................................................... 11
4.1 Concentration Display and Power Indicator Lamp................................ 11
4.2 Routine Maintenance Schedule ............................................................ 11
4.3 Loss of Power Indicator ....................................................................... 12
5: Maintenance & Calibration....................................................................... 13
5.1 Sensor Cell Removal and Installation ................................................... 13
5.2 Calibration........................................................................................... 14
5.3 Electrolyte Replenishment ................................................................... 18
5.4 Sensor Calibration Kits ........................................................................ 23

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1: Introduction
This instruction manual provides installation, operation, and maintenance
information on PureAire Monitoring System’s Model TX-KE and Model TX-KP
gas detection systems. These systems may be used as either stand-alone detection
systems, linked to dedicated controllers, or connected to facility-wide
surveillance systems. The main difference between the TX-KE and TX-KP are
the components used to make them suitable for use in hazardous areas.
1.1 Model TX-KE
1.1.1 General Information
The Model TX-KE is an intrinsically safe instrument designed to continuously
detect and measure absorptive gases such as HCl, HF, and HCHO. It is suitable
for use in Class I, Division 1, Group B, C, and D hazardous areas when used with
a safety barrier installed outside the hazardous area. Standard features include:
•Intrinsically safe
•Digital or analog concentration display
•Rapid response
•One man, non-intrusive remote calibration
•Ideal for absorptive gases
•Plug-in diffusion-type sensor cell
1.1.2 Component Identification
CN1
CN3
1 2 3 4
CMA+
Common
MA
+
TX-KE
Bionics Instrument Co., Ltd.
GAS DETECTOR
0S
24
5
6
87
1
1. Concentration Display — A local analog or digital readout which displays
the measured concentration of the target gas.
2. Zero Potentiometer — This potentiometer is used to adjust the instrument’s
4 mA analog output signal to ensure that it is transmitting a 4 mA signal
when the instrument is reading a zero gas concentration. Note: Depending on
the gas sensor a clockwise or counterclockwise rotation increases the value; a
counterclockwise or clockwise rotation decreases the value.

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3. Span Potentiometer — This potentiometer is used to adjust the span
calibration of the system. It should only be adjusted when calibrating the
instrument. Note: Depending on the gas sensor a clockwise or
counterclockwise rotation increases the value; a counterclockwise or
clockwise rotation decreases the value.
4. Cable Inlet — This is a ¾ inch NPT opening in the transmitter housing for
connecting the 4-20 mA output and 24 VDC power cable.
WARNING: This connection must be made using an explosion-proof
cable gland or connector to seal the inlet if the TX-KE is being installed
in a hazardous area.
5. Cable Connection Terminal Block — The 4-20 mA output and 24 VDC
connections are made on this terminal block. See Section 3: Installation for
more information.
6. Sensor Connection Terminal Block — The sensor connection is made at
the factory on this terminal block.
7. Sensor Cover — This cover protects the gas sensor. It threads onto the
explosion-proof housing.
8. Gas Sensor — A plug-in electrochemical sensor designed to detect a specific
gas. It outputs an electrical signal proportional to the concentration of the
target gas which is translated by the instrument’s electronics and
subsequently displayed on the local readout and output as a 4-20 mA analog
signal.
1.2 Model TX-KP
1.2.1 General Information
The Model TX-KP is an explosion-proof instrument designed to continuously
detect and measure non-absorptive gases, such as CO, H2, and oxygen. It is
suitable for use in Class I, Division 1, Group B, C and D hazardous areas.
Standard features include:
•Explosion-proof
•Digital or analog concentration display
•4-20 mA output
•Rapid response
•One man, non-intrusive remote calibration
•Low power consumption
•Ideal for non-absorptive gases
•Plug-in and disposable diffusion-type sensor cell

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1.2.2 Component Identification
CN1
CN3
1 2 3 4
CMA+
Common
MA
+
TX-KP
Bionics Instrument Co., Ltd.
GAS DETECTOR
0S
24
5
6
87
1
1. Concentration Display — A local analog or digital readout which displays
the measured concentration of the target gas.
9. Zero Potentiometer — This potentiometer is used to adjust the instrument’s
4 mA analog output signal to ensure that it is transmitting a 4 mA signal
when the instrument is reading a zero gas concentration. Note: Depending
on the gas sensor a clockwise or counterclockwise rotation increases the
value; a counterclockwise or clockwise rotation decreases the value.
10. Span Potentiometer — This potentiometer is used to adjust the span
calibration of the system. It should only be adjusted when calibrating the
instrument. Note: Depending on the gas sensor a clockwise or
counterclockwise rotation increases the value; a counterclockwise or
clockwise rotation decreases the value.
2. Cable Inlet — This is a ¾ inch NPT opening in the transmitter housing for
connecting the 4-20 mA output and 24 VDC power cable.
WARNING: This connection must be made using an explosion-proof
cable gland or connector to seal the inlet if the TX-KP is being installed
in a hazardous area.
3. Cable Connection Terminal Block — The 4-20 mA output and 24 VDC
connections are made on this terminal block. See Section 3: Installation for
more information.
4. Sensor Connection Terminal Block — The sensor connection is made at
the factory on this terminal block.
5. Sensor Cover — This cover protects the gas sensor. It threads onto the
explosion-proof housing.
6. Gas Sensor — A plug-in electrochemical sensor designed to detect a specific
gas. It outputs an electrical signal proportional to the concentration of the
target gas which is translated by the instrument’s electronics and
subsequently displayed on the local readout and output as a 4-20 mA analog
signal.

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2: Specifications
NOTE: Due to our commitment to continual product improvement, all
specifications are subject to change without notice.
2.1 Performance Specifications
Sensor Type: Diffusion type electrochemical sensors:
TX-KE — Type DP and Type HP sensors
TX-KP — Type MP, KP, and TP sensors
Accuracy: ±5% full scale.
Operating Temperature: -20° to +50°C (-4° to +122°F).
2.2 Signal Outputs
Local Readout: Analog or digital display.
Analog Output: 4-20 mA.
2.3 Electrical Requirements
Power: 24 VDC.

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3: Installation
Both Model TX-KE and Model TX-KP gas detectors are designed for installation
in Class I, Division 1, Group B, C and D hazardous areas. They may be wall or
pipe mounted with the sensor pointing straight down. The instruments should
also be kept out of direct sunlight if possible.
3.1 Wiring
WARNING: The controller or DCS that supplies power to the TX-KP must be
turned off before opening the cover of the transmitter or connecting the
transmission cable. It is the user’s responsibility to confirm that no combustible
gas is present when opening the cover of the transmitter; failure to do so could
result in an explosion.
3.1.1 General
1. Remove the transmitter cover.
2. Remove the display unit. It is held in place by two Phillips head screws
which are marked with arrows.
3. Insert the three-wire 4-20 mA / 24 VDC power transmission cable through
the cable inlet.
WARNING: An explosion-proof cable gland or connector must be used to seal
the transmission cable inlet.
4. Connect the 4-20 mA / 24 VDC power transmission cable to the terminal
block.
5. Replace the display unit.
6. Replace the transmitter cover.
3.1.2 Model TX-KE (Intrinsically Safe)
CAUTION: If the Model TX-KE is installed in a hazardous area, it must be
wired through a safety barrier installed outside of the hazardous area. PureAire
Monitoring Systems recommends the use of the Model MTL788+ Safety Barrier
for intrinsically safe wiring.
The transmission cable should be connected to terminal block CN3 in the
explosion-proof housing. The white (+) wire connects to terminal #1, the black
(-) to terminal #2, and shield (S) to terminal #3.
IMPORTANT: Do not switch the polarity of the 24 VDC power line. The white
(+24 VDC) line must connect to terminal #1 and the black (0 VDC) power line
must connect to terminal #2.

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TX-KE Transmitter
Transmission Cable Connector
Shield
Hazardous Area
1
2
3
+
-
Intrinsically Safe Earth
Non-hazardous Area
DC-24V Power Supply
+++
---
Shield Shield Shield
Max.
500 Ω
1
2
4
3
GND
LOAD
CN3
TX-KE Transmission Cable Wiring — Hazardous Areas
In the event that the TX-KE is installed in a non-hazardous area, it may be wired
as follows:
TX-KE
Bionics Instrument Co., Ltd .
GAS DETECTOR
CN1
CN3
1 2 3 4
LOAD
GND
DC 24V Power Supply
CMA
+
+ (White)
Shield
Shield
-
+
PC-1280RU
Transmission
Cable Inlet
NPT 3/4"
Transmission
Cable
2
1
Shield
- (Black)
+ (White)
- (Black)
TX-KE Transmission Cable Wiring — Non-Hazardous Areas

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3.1.3 Model TX-KP (Explosion-Proof)
The transmission cable should be connected to terminal block CN3 in the
explosion-proof housing. The white (+) wire connects to terminal #1, the black
(-) to terminal #2, and shield (S) to terminal #3.
IMPORTANT: Do not switch the polarity of the 24 VDC power line. The white
(+24 VDC) line must connect to terminal #1 and the black (0 VDC) power line
must connect to terminal #2.
TX-KP
Bionics Instrument Co., Ltd.
GAS DE TECTOR
CN1
CN3
1 2 3 4
LOAD
GND
DC 24V Power Supply
C
MA+
Shield
Shield
-
+
PC-1280RU
Transmission
Cable Inlet
NPT 3/4"
Transmission
Cable
2
1
Shield
+(White)
-(Black)
+(White)
- (Black)
TX-KP Transmission Cable Wiring

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3.2 Sensor Installation
3.2.1 Shorting Plug
Some sensors are shipped with a shorting plug between the “W” and “C” pins on
the sensor cell. This must be removed prior to installation.
Short Pin
Sensor Cell — Top View
3.2.2 Sensor Installation
1. Remove the sensor cover.
2. Plug the sensor cell into the bottom of the transmitter.
3. Replace the sensor cover.
ZERO SPAN ZERO SPAN ZERO SPAN ZERO SPAN
NOTE The internal wiring to the sensor cell terminal connector on the
transmitter printed circuit board is terminated at the factory. It is not necessary
to make internal wiring terminations. If necessary, the terminal connector may
be removed from the printed circuit board to make these connections. Be sure to
replace the terminal connector securely once all connections have been made

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Sensor Cable Type Wire Color Location
3-electrode sensor Black
White
Red
Open
Terminal 1
Terminal 2
Terminal 3
Terminal 4
2-electrode sensor Open
White
Black
Shield
Terminal 1
Terminal 2
Terminal 3
Terminal 4
1 2 3 4
SENSOR CABLE
white
black
shield
2-Electrode Sensor Wiring
3-Electrode Sensor Wiring

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4: Normal Operation
Model TX-KE and TX-KP gas detectors are designed for use with a PureAire
controller or other control system capable of receiving a 4-20 mA signal.
During normal operation, the instrument will display the measured gas
concentration on its local analog or digital readout and output a corresponding
4-20 mA analog signal.
4.1 Concentration Display and Power Indicator Lamp
NOTE: The following applies to both the Model TX-KE and Model TX-KP.
4.1.1 Concentration Display
This is a real time display of the measured concentration of the target gas. The
target gas and units of measure (PPM, PPB, etc.) are indicated on the front of the
instrument.
4.1.1 Power LED
This LED is lit when the instrument is operating properly. It will get brighter as
the measured gas concentration increases.
4.2 Routine Maintenance Schedule
Continuous gas detection systems depended upon to measure and detect
hazardous gas leaks require periodic maintenance to ensure proper operation. The
frequency with which this routine maintenance is required depends on the
environment, since temperature, humidity, gas concentrations, and dust all affect
system operation.
The following table is intended to serve as a general guideline for routine
maintenance. The conditions in your particular application, as well as your
organization’s maintenance policies, will ultimately determine the best routine
maintenance schedule for your equipment.
4.2.1 Routine Visual Checks
Items to check Check for power and proper operation
Condition / status when
operating properly
Should read “0” when no gas is present; analog
output signal at 4 mA.
Corrective actions If meter reads higher than “0” in a zero gas
condition, adjust as required to the environment

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4.2.2 Recommended Routine Maintenance Schedule
Routine Visual
Checks
Monthly Comments
Electrolyte
Replacement
Every 6
months
Model TX-KE only; Model TX-KP uses a
disposable sensor cell. When replacing
electrolyte, fresh electrolyte should be added
until it reaches the top of the gauge on the
side of the sensor. Should the electrolyte
level fall below the ¼ mark before the 6-
month replacement interval is over, it should
be replaced.
Sensor O-ring
and Membrane
Replacement
Every 6
months
Model TX-KE only; Model TX-KP uses a
disposable sensor cell. The membrane
should be checked occasionally for dirt and
oil substances between replacement
intervals and replaced if dirty, soiled by oil, or
damaged.
Sensor
Calibration
Every 6
months
Calibration should be performed whenever
the electrolyte or membrane is replaced.
Sensor
Replacement
Every 2
years
Model TX-KP only; Model TX-KE uses a
renewable sensor. Estimated sensor life is
two years, although life may vary depending
on the installation. Replacement is required
when the instrument can no longer be zeroed
or calibrated correctly.
4.3 Loss of Power Indicator
In the event the TX-KE or TX-KP loses VDC power, the 4-20 mA analog output
signal drops to 0. The green LED on the face of the instrument will also go out.

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5: Maintenance & Calibration
Maintenance and calibration should be performed only by qualified personnel.
5.1 Sensor Cell Removal and Installation
Model TX-KE and TX-KP gas detectors use a plug-in sensor cell which is
extremely simple to remove and install.
5.1.1 Sensor Cell Removal
1. Remove the sensor cover.
2. Unplug the sensor cell by pulling straight down. Take care not to twist the
sensor cell.
TX-KE
Bionics Instrument Co ., Ltd.
GAS DETECTOR
TX-KE
Bionics Instrument Co ., Ltd.
GAS DETECTOR
Model TX-KE
TX-KP
Bionics Instrumen t Co., Ltd.
GAS DETECTOR
TX-KP
Bionics Instrumen t Co., Ltd.
GAS DETECTOR
Model TX-KP

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5.1.2 Sensor Cell Installation
1. Remove the sensor cover (as required).
2. Plug the sensor cell into the bottom of the transmitter.
3. Replace the sensor cover.
NOTE: If a new sensor cell is being installed, check for the presence of a
shorting plug and remove it before installation. See Section 3.2.1 for more
information.
Short Pin
Sensor Cell — Top View
5.2 Calibration
Model TX-KE and TX-KP gas detectors require periodic calibration with the
appropriate standard gas. PureAire Calibration Kits (optional) are recommended
for calibration purposes (see Section 5.4).
WARNING: Before performing a calibration, it is the user’s responsibility to
confirm that they area is free of combustible gas.
IMPORTANT: If the TX-KE or TX-KP is connected to an external alarm or
control system, the alarm or control system should be disabled or placed in a
standby mode during calibration to avoid an accidental alarm.
5.2.1 General
1. Remove the cover of the calibration port (located on the left hand side of the
instrument housing).
2. Remove the sensor cover.
3. Place the calibration adapter over the sensor cell.

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TX-KE
Bionics Instrument Co., Ltd.
GAS DETECTOR
0S
Calibration Port
Zero Adjustment
Span Adjustment
2
3
Zero and Span Potentiometers
TX-KE
Bionics Ins trument Co ., Ltd .
GAS DETECTOR
TX-KE
Bionics Instru ment Co ., Ltd .
GAS DETECTOR
TX-KE
Bionics Ins trument Co ., Ltd .
GAS DETECTOR
Calibration Adapter — Model TX-KE
TX-KP
Bionics In strumen t Co., Ltd.
GAS DETECTOR
TX-KP
Bionics Instrumen t Co., Ltd.
GAS DETECTOR
TX-KP
Bionics Instrument Co., Ltd.
GAS DETECTOR
Calibration Adapter — Model TX-KP

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5.2.2 Zero Calibration
IMPORTANT: This procedure should be performed under normal monitoring
conditions, without any of the target gas present.
1. Check the instrument’s gas concentration reading on the local display.
2. If the display does not read a steady “0,” adjust the zero potentiometer as
required. Note: Depending on the gas sensor a clockwise or counterclockwise
rotation increases the value; a counterclockwise or clockwise rotation decreases
the value.


NOTE: On units shipped through Nov 2008, the digital display does not
display a negative sign. The lowest zero setting will indicate 0.02 or 0.2ppm.
When adjusting zero, turn the pot until the display reading increases, and then
turn it back down until the reading indicates 0.00 or 0.0. This will insure that
you are in the positive range of the display setting.
 Units manufactured in 2009 display a negative sign.
5.2.3 Span Calibration
CAUTION: Be sure to observe all safety guidelines when generating and using
calibration gases.
NOTE: Gas generation kits are available through PureAire. These kits include
instructions and materials for generating calibration gases and precise methods
for accurately measuring the concentration of these gases.
NOTE: The gas concentration should be close to, but never exceed, full scale.
1. Connect the appropriate calibration cap to the inlet of the high flow sampling
pump and connect the Tedlar “waste gas” bag to the outlet of the pump.
2. Open the valve on the waste gas bag.
3. Connect the flowmeter to the inlet of the calibration cap and turn the high
flow sampling pump “on.”
4. Adjust the pump’s flowrate potentiometer until a flowrate of 0.5 liters/minute
(0.2 liters/minute for hydride sensors) is achieved. A clockwise rotation
increases flow; a counter-clockwise rotation decreases flow.
5. Recheck the instrument’s zero reading; adjust as required.
6. Generate the calibration gas within a Tedlar bag.
IMPORTANT: Be sure to perform the calibration before the concentration of
the gas changes. Also, PureAire recommends that you verify that the
concentration of the calibration gas is the same after calibration as it was before.
7. Disconnect the flowmeter and connect the Tedlar calibration gas bag to the
inlet side of the calibration cap.
8. Open the valve on the calibration gas bag.
9. Expose the sensor cell to the span gas for 1 to 2 minutes until the gas reading
stabilizes.

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11. Adjust the instrument’s span potentiometer until the displayed gas reading
matches the concentration value of the calibration gas. Note: Depending on
the gas sensor a clockwise or counterclockwise rotation increases the value; a
counterclockwise or clockwise rotation decreases the value.
10. Close the valve on the calibration gas bag and permit the instrument to return
to a zero reading.
11. Open the valve on the calibration gas bag and verify that the display reading
matches the concentration of the calibration gas. Readjust the span
potentiometer as required.
12. Close the valve on the calibration gas bag and disconnect it from the
calibration cap.
13. Allow the instrument to return to a zero reading. If the instrument has not
returned to zero after 5 minutes, readjust the zero potentiometer as required.
14. Close the valve on the waste gas bag and disconnect from the sampling
pump.
15. Turn the sampling pump “off.”
16. Carefully remove the calibration cap from the sensor cell.
IMPORTANT: Do not twist the calibration cap for D-type or renewable sensor
cells.
17. Replace the calibration port cover.
18. If the instrument is connected to a controller, return the controller to the
monitoring mode.
WARNING: Be sure to dispose of the remaining calibration gas and waste gas
properly.
Calibration Adapter

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5.3 Electrolyte Replenishment Renewable sensor cells
CAUTION: Be sure to adhere to your facility’s chemical handling guidelines
and procedures.
1. Remove the sensor as outlined in Section 5.1.1.
2. Remove the box nut, membrane retainer ring, membrane,
O-ring, and silicon sheet (depending on sensor model).
Box Nut
Membrane Retainer Ring
Membrane
O-ring
Sensing Electrode
Silicon Sheet
3. Place the sensor over the beaker as shown and pour the old electrolyte into
the beaker.
Pressure
Compensation
Screw
Beaker for
Old Electrolyte

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4. Hold the sensor in your hand with the sensing electrode up. Pour 10 cc’s of fresh electrolyte into the
sensor and rinse. Discard into the beaker.
Sensing Electrode
Nozzled Electrolyte
Bottle
Pressure Compensation Port
Electrolyte
5. Place the sensor over the beaker as shown and pour the rinsed electrolyte
into the beaker.
Pressure
Compensation
Screw
Beaker for
Old Electrolyte