RKI INSTRUMENTS 65-2396RK-XX-04 CO2 IR Carbon Dioxide Sensor Transmitter Instruction Manual

June 1, 2024
RKI INSTRUMENTS

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RKI INSTRUMENTS 65-2396RK-XX-04 CO2 IR Carbon Dioxide Sensor Transmitter

RKI-INSTRUMENTS-65-2396RK-XX-04-CO2-IR-Carbon-Dioxide-Sensor-Transmitter-
PRODUCT

Specifications

  • Product Name: CO2 Transmitter
  • Model Number: 65-2396RK-XX-04
  • Part Number: 71-0656
  • Revision: P1
  • Released Date: 1/16/24
  • Manufacturer: RKI Instruments, Inc.
  • Website:www.rkiinstruments.com

Description

  • The CO2 Transmitter is designed to measure and transmit carbon dioxide levels in a given environment.
  • It is essential for maintaining air quality and ensuring safety in various settings.

Installation

To install the CO2 Transmitter, follow these steps:

  1. Mounting the CO2 Transmitter:
    • Locate a suitable location for mounting the transmitter.
    • Secure the transmitter in place using the appropriate mounting hardware.
  2. Wiring the Detector to the Amplifier:
    • Connect the detector to the amplifier following the provided wiring diagram.
  3. Wiring the Amplifier to a Controller:
    • Connect the amplifier to a compatible controller using the appropriate cables.

Startup

When starting up the CO2 Transmitter, make sure to:

  1. Introduce Incoming Power:
    • Connect the transmitter to a power source as specified in the manual.
  2. Setting the Zero Signal:
    • Adjust the zero signal according to the calibration instructions provided.

Maintenance

Regular maintenance is crucial for optimal performance. Follow these maintenance tasks:

  1. Preventive Maintenance:
    • Regularly clean and inspect the transmitter for any damage or debris.
  2. Troubleshooting:
    • Refer to the troubleshooting section in the manual for common issues and solutions.
  3. Replacing Components of the CO2 Transmitter:
    • When necessary, replace components following the detailed instructions provided.

Calibration

It is recommended to calibrate the CO2 Transmitter at regular intervals. Follow these steps:

  1. Calibration Frequency:
    • Refer to the calibration frequency guidelines provided in the manual.
  2. Calibration Process:
    • Follow the step-by-step calibration instructions to ensure accurate readings.

Parts List

For a detailed list of parts included with the CO2 Transmitter, please refer to the parts list section in the manual.

FAQ

Q: How often should I calibrate the CO2 Transmitter?

A: The calibration frequency for the CO2 Transmitter is recommended every [frequency mentioned in manual].

Q: What should I do if the transmitter displays an error message?

A: If you encounter an error message, refer to the troubleshooting section of the manual for detailed steps to resolve common issues.

WARNING

  • Read and understand this instruction manual before operating the transmitter. Improper use of the transmitter could result in bodily harm or death.
  • Periodic calibration and maintenance of the transmitter is essential for proper operation and correct readings. Please calibrate and maintain this transmitter regularly!
  • The frequency of calibration depends upon the type of use you have and the sensor types. Typical calibration frequencies for most applications are between 9 and 12 months but can be required more often or less often based on your usage.

Product Warranty

  • RKI Instruments, Inc. warrants gas alarm equipment sold by us to be free from defects in materials, workmanship, and performance for one year from the date of shipment from RKI Instruments, Inc.
  • Any parts found defective within that period will be repaired or replaced, at our option, free of charge.
  • This warranty does not apply to those items which by their nature are subject to deterioration or consumption in normal service, and which must be cleaned, repaired, or replaced on a routine basis.

Examples of such items are:

  • Absorbent cartridges
  • Fuses
  • Pump diaphragms and valves
  • Batteries
  • Filter elements
  • Warranty is voided by abuse including mechanical damage, alteration, rough handling, or repair procedures not under the operator’s manual.
  • This warranty indicates the full extent of our liability, and we are not responsible for removal or replacement costs, local repair costs, transportation costs, or contingent expenses incurred without our prior approval.
  • THIS WARRANTY IS EXPRESSLY IN PLACE OF ANY AND ALL OTHER WARRANTIES AND REPRESENTATIONS, EXPRESSED OR IMPLIED, AND ALL OTHER OBLIGATIONS OR LIABILITIES ON THE PART OF RKI INSTRUMENTS, INC. INCLUDING BUT NOT LIMITED TO, THE WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL RKI INSTRUMENTS, INC. BE LIABLE FOR INDIRECT, INCIDENTAL, OR CONSEQUENTIAL LOSS OR DAMAGE OF ANY KIND CONNECTED WITH THE USE OF ITS PRODUCTS OR FAILURE OF ITS PRODUCTS TO FUNCTION OR OPERATE PROPERLY.
  • This warranty covers instruments and parts sold to users by authorized distributors, dealers, and representatives as appointed by RKI Instruments, Inc.
  • We do not assume indemnification for any accident or damage caused by the operation of this gas monitor, and our warranty is limited to the replacement of parts or our complete goods.

Overview

  • This manual describes the 65-2396RK-XX-04 CO2 transmitter. This manual also describes how to install, start-up, configure, maintain, and calibrate the transmitter when it is used with a gas monitoring controller.
  • A parts list at the end of this manual lists replacement parts and accessories for the CO2 transmitter.

Specifications

Table 1 lists the specifications for the 65-2396RK-XX-04 CO2 transmitter.

Table 1: Specifications

Target Gas Carbon Dioxide (CO2)
Area Classification Explosion-proof for Class I, Groups B, C, and D
Sampling Method Diffusion
Signal Output 4 to 20 mA
Detection Range 65-2396RK-01-04: 0-9,000 ppm

65-2396RK-02-04: 0-5,000 ppm

65-2396RK-03-04: 0-5% volume (vol.)

65-2396RK-04-04: 0-20% vol.

65-2396RK-05-04: 0-50% vol.

65-2396RK-10-04: 0-100% vol.

Response Time| 90% in 45 seconds
Operating Temperature| -4°F to 122°F (-20°C to 50°C)
Accuracy| ± 5% of reading or ± 2% of full scale (whichever is greater)

  • WARNING: When using the 65-2396RK-XX-04, you must follow the instructions and warnings in this manual to ensure proper and safe operation of the 65-2396RK-XX-04 and to minimize the risk of personal injury.
  • Be sure to maintain and periodically calibrate the 65-2396RK-XX-04 as described in this manual.

Description

  • This section describes the components of the CO2 transmitter. The transmitter is a 4 – 20 mA type detector head. It consists of the CO2 detector, the amplifier, the amplifier junction box, and the detector junction box.
  • The two-junction-box configuration is intended for situations where the detector needs to be installed at an inaccessible location.
  • The detector junction box can be installed at the inaccessible location and the amplifier junction box can be installed in a more readily accessible area. RKI-INSTRUMENTS-65-2396RK-XX-04-CO2-IR-Carbon-Dioxide-Sensor-Transmitter-FIG-1

Infrared CO2 Detector

  • The CO2 detector is made up of a miniature infrared CO2 detector housed and encapsulated in a pipe nipple. The pipe nipple has 3/4 NPT threads on each end and a 1 1/4” hex that allows removal or installation of the detector with a wrench. A porous flame arrestor that is coated with a hydrophobic film that repels liquids is on one end of the detector and allows sample gas to enter the detector.
  • Four color-coded leads, red, white, green, and black, extend from the other end of the detector. The leads allow you to connect the detector to the amplifier.
  • To distinguish the different ranges of CO2 detectors from one another, a short length of shrink tubing is applied to the wiring where it comes out of the nipple.
  • The following table indicates the color of the shrink tubing and the color of the wire to which it is applied.

Table 2: Detector Color Designations

Detector Range Shrink Tubing Color Designations
0 – 5,000 ppm black shrink tubing on white wire
0 – 9,000 ppm black shrink tubing on green wire
0 – 5% vol. green shrink tubing on white wire
0 – 20% vol. black shrink tubing on the red wire
0 – 50% vol. green shrink tubing on the red wire
0 – 100% vol. red shrink tubing on green wire
  • The output of the CO2 detector mimics the output of RKI’s standard catalytic LEL detectors. For this reason, the CO2 detector’s wire colors are the same as RKI’s catalytic LEL detectors, black, white, green, and red.
  • When the CO2 detector is wired to an RKI controller, it is wired the same way an LEL detector is wired, to the LEL detector terminals. See “Wiring the Detector to the Amplifier” on page 11 for wiring connections.

Calibration Cup/Splash Guard

  • A calibration cup/splash guard is installed on the IR CO2 detector. A fitting at the bottom of the calibration cup/splash guard allows a length of tubing to be connected for calibration and routed to a more easily accessible location.
  • The calibration cup/splash guard also protects the detector.

Amplifier

  • The amplifier converts the electrical output from the detector to a 4 to 20 mA signal that corresponds to the detection range and transmits the signal to a gas monitoring controller.
  • A foam gasket that orients the amplifier and keeps it from rotating is installed on the bottom of the amplifier.
  • The amplifier includes the controller terminal strip, detector terminal strip, span pot, zero pot, and test points (see Figure 2).RKI-INSTRUMENTS-65-2396RK-XX-04-CO2-IR-Carbon-Dioxide-Sensor-Transmitter-FIG-2

Controller Terminal Strip

  • The controller terminal strip is a three-position plug-in-style terminal strip located near the top of the amplifier. Use the controller terminal strip to wire the CO2 transmitter to a controller.

Detector Terminal Strip

  • The detector terminal strip is a four-position plug-in-style terminal strip located below the controller terminal strip. Use the detector terminal strip to connect the CO2 transmitter to the amplifier.
  • NOTE: The IR CO2 detector is factory-wired to the detector terminal strip. See “Wiring the Amplifier to a Controller” on page 13 for all wiring procedures related to the transmitter.

Zero Pot

  • The zero pot is located in the upper left corner of the amplifier (see Figure 1). Use a small flat-blade screwdriver to turn the zero pot’s adjustment screw and adjust the amplifier’s target gas-free output during the start-up and calibration procedures.
  • Turn the adjustment screw clockwise to increase the zero output and counterclockwise to decrease the zero output.

Span Pot

  • The span pot is located to the right of the zero pot (see Figure 1). Use a small flat-blade screwdriver to turn the span pot’s adjustment screw and adjust the amplifier’s gas response output during the calibration procedure.
  • Turn the adjustment screw clockwise to increase the gas response and counterclockwise to decrease the gas response.
  • CAUTION: The amplifier includes two additional potentiometers. They are factory-set. Do not adjust them.

Test Points

  • The test points are on the left side of the amplifier (see Figure 1). The test points produce a 100 mV to 500 mV output that corresponds to the transmitter’s 4 to 20 mA output.
  • Use the test points and a voltmeter to measure the amplifier’s output during the start-up and calibration procedures.
  • The black test point in the lower left corner is the negative (-) test point and the red test point below the zero pot is the positive (+) test point.

Amplifier Junction Box

  • The amplifier junction box protects the amplifier and wiring connections made to the amplifier.
  • Use the top 3/4 NPT conduit hub to connect the wiring from the amplifier to the controller. Use the bottom 3/4 NPT conduit hub to wire the remotely installed CO2 detector.
  • Use the cover on the front of the junction box to access the interior of the junction box. The amplifier is factory-installed in the junction box.
  • Three spacers installed on the back of the junction box control the distance of the junction box from a mounting surface.

Detector Junction Box

  • The detector junction box is intended to be installed remotely from the amplifier junction box.
  • The CO2 detector is factory-installed in the bottom 3/4 NPT conduit hub. A terminal strip is provided for wiring connections and the detector is factory wired to one side of this terminal strip.
  • The other side of the terminal strip is for user-supplied wiring to the detector terminal strip located in the amplifier junction box.
  • This wiring should go through the top 3/4 NPT conduit hub.
  • Three spacers installed on the back of the junction box control the distance of the junction box from a mounting surface.

Installation

This section describes procedures for mounting the CO2 transmitter in the monitoring environment and wiring the transmitter to a controller.

Mounting the CO2 Transmitter

  1. Select a mounting site that is representative of the monitoring environment. Consider the following when you select the mounting site:
    • For the amplifier junction box, select a site where the junction box is not likely to be bumped or disturbed. Make sure there is sufficient room to perform start-up, maintenance, and calibration procedures. The site should be easily accessible.
    • For the detector junction box, select a site where the target gas is likely to be found first.
    • For carbon dioxide, mount the remote detector at least six feet from the floor to minimize the possibility of someone breathing on the unit. The exhaled CO2 may cause an alarm.
    • The junction boxes should be mounted no further than 200 feet from each other.
  2. At the monitoring site you select, hang, or mount the junction box with the detector facing down (see Figure 2).RKI-INSTRUMENTS-65-2396RK-XX-04-CO2-IR-Carbon-Dioxide-Sensor-Transmitter-FIG-3

Wiring the Detector to the Amplifier

WARNING: Always verify that the power to the controller is off before you make wiring connections.

  1. Confirm that no power is being applied to the amplifier. If the amplifier has already been connected to a controller, turn off the controller and turn off or unplug power to the controller.
  2. Remove the detector junction box’s cover from the junction box.
  3. Remove the amplifier junction box’s cover from the junction box.
  4. Guide a four-conductor, shielded cable, or four wires in conduit through the top conduit hub of the detector junction box. To make wiring more convenient, use wire colors that correspond to the detector wire colors: red, white, green, and black.
    • NOTE: Consult RKI Instruments, Inc. for cable lengths longer than 200 feet.
  5. Connect the detector leads to the terminal block in the detector junction box.
  6. Secure the detector junction box’s cover to the junction box.
  7. Guide the other end of the four-conductor, shielded cable, or four wires in conduit through the bottom conduit hub of the amplifier junction box.
  8. To gain access to a plug-in terminal strip for wiring, pull it out of its socket by grasping the terminal strip and pulling. The detector strip is keyed so that the controller and detector terminal strips cannot be reversed inadvertently.
  9. Pull out the detector terminal strip and connect the four wires to the terminal strip as follows (see Figure 4).
    • Connect the wire corresponding to the detector’s red wire to the LEL “R” terminal.
    • Connect the wire corresponding to the detector’s white wire to the LEL “W” terminal.
    • Connect the wire corresponding to the detector’s green wire to the LEL “G” terminal.
    • Connect the wire corresponding to the detector’s black wire to the LEL “B” terminal.
    • CAUTION: If a shielded cable is used, leave the cable shield’s drain wire disconnected and insulated at the detector junction box.
    • You will connect the opposite end of the cable’s drain wire to the amplifier junction box’s chassis (earth) ground.RKI-INSTRUMENTS-65-2396RK-XX-04-CO2-IR-Carbon-Dioxide-Sensor-Transmitter-FIG-4
  10. Reinstall the detector terminal strip into its socket.
  11. If a shielded cable is used, connect the cable’s drain wire to an available chassis (earth) ground at the amplifier junction box. The amplifier mounting screw is a convenient grounding location. Install a lug on the shield drain wire or wrap the shield drain wire around the mounting screw. Do not connect the shield drain wire at the detector junction box.

WARNING: Always verify that the power to the controller is off before you make wiring connections.

  1. 1. Turn off the controller.

  2. 2. Turn off or unplug power to the controller.

  3. 3. Remove the amplifier’s junction box cover.

  4. 4. Guide a three-conductor, shielded cable, or three wires in conduit through the top conduit hub of the junction box.

  5. 5. Pull out the controller terminal strip, and connect the three wires to the terminal strip as follows (see Figure 5).

    • Connect the positive wire to the PWR/SIG “+” terminal.
    • Connect the signal wire to the PWR/SIG “S” terminal.
    • Connect the negative wire to the PWR/SIG “-” terminal.
    • CAUTION: If shielded cable is used, leave the cable shield’s drain wire disconnected and insulated at the transmitter. You will connect the opposite end of the cable’s drain wire to the controller’s chassis (earth) ground.
  6. Reinstall the controller terminal strip into its socket.

  7. Secure the junction box cover to the junction box.

  8. Route the cable or wires leading from the amplifier junction box through one of the conduit hubs at the controller housing. Use appropriate conduit fittings and construction techniques for the environmental rating of the controller. RKI controllers are typically rated NEMA 4X, are not explosion-proof, and must be installed in a non-hazardous location.
    CAUTION: Do not route power and transmitter wiring through the same controller conduit hub. The power cable may disrupt the transmission of the transmitter signal to the controller.

  9. Connect the wires to the applicable detector/transmitter terminal strip at the controller as shown in Figure 5.RKI-INSTRUMENTS-65-2396RK-XX-04-CO2-IR-Carbon-Dioxide-Sensor-Transmitter-FIG-5

  10. If a shielded cable is used, connect the cable’s drain wire to an available chassis (earth) ground at the controller. RKI controllers typically have a ground stud that can be used to ground the cable’s drain wire.

Start-Up

This section describes procedures to start up the CO2 transmitter and place the transmitter into normal operation.

Introducing Incoming Power

  1. Complete the installation procedures described earlier in this manual.
  2. Verify that the power wiring to the controller is correct and secure. Refer to the controller operator’s manual.
  3. Turn on the power to the controller.
  4. Turn on the controller.
  5. Verify that the controller is on and operating properly. Refer to the controller operator’s manual.
    • NOTE: When first powered up, the transmitter will enter about a one-minute period when the 4-20 mA output is stabilizing and may be above the controller alarm points or well below zero momentarily. RKI controllers have a one-minute warmup period when the controller does not display any gas reading or give any alarm indication. The CO2 transmitter’s 4-20 mA signal should be stable by the time the controller’s warmup period is over.
    • CAUTION: Allow the detector to warm up for 5 minutes before you continue with the next section, “Setting the Zero Signal”.

Setting the Zero Signal

  • Since there is a background of CO2 in the air of typically 300 – 600 ppm (0.03 – 0.06% volume), it is necessary to use a calibration kit with a 100% nitrogen cylinder to set the zero signal of a CO2 transmitter with a low-range detector.
  • Fresh air can be used to zero the transmitter if a 0-20% volume, 0-50% volume, or 0-100% volume detector is being used.
  • WARNING: Do not remove the junction box cover while the circuits are energized unless the area is determined to be non-hazardous. Keep the junction box cover tightly closed during operation.
  • The procedure below describes applying 100% nitrogen using a calibration kit that includes a calibration cup, calibration gas, sample tubing, and a fixed flow regulator with an on/off knob.
  • RKI Instruments, Inc. recommends using a 0.5 LPM (liters per minute) fixed flow regulator.
  1. Unscrew and remove the junction box cover from the junction box.
  2. Set a voltmeter to measure in the millivolt (mV) range.
  3. Plug the voltmeter leads into the test points on the amplifier. Plug the positive lead into the red (+) test point; plug the negative lead into the black (-) test point.
  4. Screw the calibration cup onto the bottom of the IR CO2 detector.
  5. Screw the regulator into the 100% nitrogen calibration cylinder.
  6. Use the calibration kit sample tubing to connect the regulator to the calibration cup.
  7. Turn the regulator’s on/off knob counterclockwise to open it. Gas will begin to flow.
  8. Allow the gas to flow for one minute.
  9. Verify a voltmeter reading of 100 mV (±2 mV).
  10. If necessary, use a small flat-blade screwdriver to adjust the zero pot until the voltmeter reading is 100 mV (±2 mV).
  11. Turn the regulator’s on/off knob clockwise to close it.
  12. Unscrew the calibration cup from the detector.
  13. Unscrew the regulator from the 100% nitrogen calibration cylinder. For convenience, leave the sample tubing connected to the regulator and the calibration cup.
  14. Store the components of the calibration kit in a safe and convenient place.
  15. Remove the voltmeter leads from the test points.
  16. Secure the junction box cover to the junction box.

Maintenance

This section describes maintenance procedures. It includes preventive maintenance, troubleshooting, and component replacement procedures.

Preventive Maintenance

This section describes a preventive maintenance schedule to ensure the optimum performance of the CO2 transmitter. It includes daily and biannual procedures.

Daily

Verify a display reading at the controller of the background concentration of CO2. Typical background concentrations of CO2 vary from about 300 to 600 ppm (0.03 to 0.06% volume) depending on location. The 0-5,000 ppm, 0-9,000 ppm, and 0-5% volume detectors will display a reading in a fresh air environment because they have low ranges. The 0-20% volume, 0-50% volume, and 0-100% volume detectors will not display a reading in fresh air because their ranges are too large. Investigate significant changes in the display reading.

Biannually

Calibrate the CO2 transmitter as described in “Calibration” on page 21 of this manual.

Troubleshooting

  • The troubleshooting guide describes symptoms, probable causes, and recommended action for problems you may encounter with the CO2 transmitter.
  • NOTE: This troubleshooting guide describes transmitter problems only. See the controller operator’s manual for problems you may encounter with the controller.

Table 3: Troubleshooting the CO2 TransmitterRKI-INSTRUMENTS-65-2396RK-
XX-04-CO2-IR-Carbon-Dioxide-Sensor-Transmitter-FIG-6

Replacing Components of the CO2 Transmitter

This section includes procedures to replace the entire CO2 detector assembly and the amplifier.

Replacing the IR CO2 Detector

  1. Turn off the controller.
  2. Turn off or unplug the power to the controller.
  3. Remove the junction box cover.
  4. Remove the detector terminal strip from its socket.
  5. Disconnect the detector leads from the detector terminal strip. Note the position of the color-coded leads as you remove them.
  6. Unscrew the detector from the junction box.
  7. Guide the detector leads of the replacement detector through the bottom conduit hub of the junction box, then screw the mounting threads of the detector into the conduit hub. If necessary for environmental conditions, apply thread sealant or Teflon tape to the hub and/or detector threads to seal them.
  8. Connect the detector leads to the detector terminal strip as shown in Table 4 below and Figure 5 on page 14 of this manual.
    • Table 4: Reconnecting the CO2 Detector to the Amplifier**
      Detector Lead| Detector Terminal Strip**
      ---|---
      Red| LEL “R”
      White| LEL “W”
      Green| LEL “G”
      Black| LEL “B”
  9. Reinstall the detector terminal strip into its socket.
  10. Reinstall the junction box cover.
  11. Turn on or plug in power to the controller.
  12. Turn on the controller and place it into normal operation.
    • NOTE: When first powered up, the transmitter will enter about a one-minute period when the 4-20 mA output is stabilizing and may be above the controller alarm points or well below zero momentarily.
    • RKI controllers have a one-minute warmup period when the controller does not display any gas reading or give any alarm indication. The CO2 transmitter’s 4-20 mA signal should be stable by the time the controller’s warmup period is over.
    • CAUTION: Allow the replacement detector to warm up for 5 minutes before you continue with the next step.
  13. Calibrate the transmitter as described in “Calibration” on page 21 of this manual.

Replacing the Amplifier

  1. Turn off the controller.
  2. Turn off or unplug the power to the controller.
  3. Remove the junction box cover.
  4. Unplug the detector terminal strip and controller terminal strip from their sockets. You may leave the wires connected to the terminal strips.
  5. Unscrew and remove the screw with the flat and lock washers that secure the amplifier to the junction box.
  6. Remove the old amplifier.
  7. Place the new amplifier in the same position as the old amplifier. A foam gasket that orients the amplifier and keeps it from rotating is installed on the bottom of the amplifier. Make sure the amplifier is seated flat in the junction box.
  8. Install the new amplifier into the junction box with the screw, lock washer, and flat washer you removed in Step 5 above.
  9. Install the detector and controller terminal strips into their sockets on the new amplifier as shown in Figure 5 on page 14 of this manual. If controller leads or detector leads were removed during this procedure, refer to Table 5 and Table 6 below.
    • Table 5: Reconnecting the Amplifier to the Controller**
      Amplifier Controller Terminal Strip| Controller Transmitter Terminal Strip (typical)**
      ---|---
      PWR/SIG “-”| – (DC -)
      PWR/SIG “S”| S (4 – 20 mA In)
      PWR/SIG “+”| + 24V
    • Table 6: Reconnecting the CO2 Detector to the Amplifier**
      Amplifier Detector Terminal Strip| **

Detector Lead

---|---
DETECTOR “R”| RED
DETECTOR “W”| WHAT
DETECTOR “G”| GREEN
DETECTOR “B”| BLK

  • NOTE: When a transmitter is first powered up with a new amplifier, the initial output may be either high or below zero depending on the setting of the zero pot. Be sure to make arrangements so that this does not cause unwanted alarms.
  1. Turn on the power to the controller.

  2. Turn on the controller and place it into normal operation.

    • NOTE: When first powered up, the transmitter will enter about a one-minute period when the 4-20 mA output is stabilizing and may be above the controller alarm points or well below zero momentarily.
    • RKI controllers have a one-minute warmup period when the controller does not display any gas reading
      or give any alarm indication. The CO2 transmitter’s 4-20 mA signal should be stable by the time the controller’s warmup period is over.
  3. Allow the transmitter to warm up for 5 minutes.

  4. Calibrate the transmitter as described in “Calibration” on page 21 of this manual.

Calibration Frequency

  • Although there is no particular calibration frequency that is correct for all applications, a calibration frequency of every 6 months is adequate for most infrared CO2 transmitter applications.
  • Unless experience in a particular application dictates otherwise, RKI Instruments, Inc. recommends a calibration frequency of every 6 months.
  • If an application is not very demanding, for example, detection in a clean, temperature-controlled environment where calibration adjustments are minimal at calibration, then a calibration frequency of every 9 to 12 months is adequate.
  • If an application is very demanding, for example, if the environment is not well controlled, then more frequent calibration than every 6 months may be necessary.

Calibration

  • This section describes how to calibrate the CO2 transmitter. It includes procedures to prepare for calibration, set the zero reading, set the response reading, and return to normal operation.
  • WARNING: The controller is not an active gas monitoring device during the calibration procedure.
  • NOTE: The following procedure assumes the use of a calibration kit which includes a calibration gas cylinder, a 100% nitrogen cylinder, a 0.5 LPM fixed flow regulator with an on/off knob, a calibration cup for the detector, and a short piece of sample tubing to connect the regulator to the calibration cup.

Preparing for Calibration

  1. Unscrew and remove the junction box cover.
  2. Set a voltmeter to measure in the millivolt (mV) range.
  3. Plug the voltmeter leads into the test points on the amplifier. Plug the positive lead into the red (+) test point; plug the negative lead into the black (-) test point.
  4. Use the following formula to determine the correct test point output for the calibrating sample.
    • Output (mV) = (calibrating sample/fullscale) X 400 + 100
    • For example, with a calibrating sample of 2.5 %Vol. and a fullscale setting of 5 %Vol., the correct output is 300 mV.
    • 300(mV) = (50/100) X 400 +100
  5. Screw the calibration cup onto the detector housing.
  6. Place the controller into its calibration mode or disable external alarms.

NOTE: Calibrating the CO2 transmitter may cause alarms. Be sure to put the controller into its calibration mode or disable external alarms before continuing.

Setting the Zero Reading

  • Since there is a background of CO2 in an air of typically 300 – 600 ppm (0.03 – 0.06% volume), it is necessary to use a calibration kit with a 100% nitrogen cylinder to set the zero signal of a CO2 transmitter with a low-range detector.
  • Fresh air can be used to zero the transmitter if a 0-20% volume, 0-50% volume, or 0-100% volume detector is being used.
  1. Screw the regulator into the 100% nitrogen calibration cylinder.
  2. Use the calibration kit sample tubing to connect the regulator to the calibration cup.
  3. Turn the regulator’s on/off knob counterclockwise to open the regulator.
  4. Allow the gas to flow for one minute and verify a reading of 100 mV (±2 mV). If necessary, use the zero pot on the amplifier to adjust the reading to 100 mV (±2 mV).
  5. Turn the regulator’s on/off knob clockwise to close the regulator.
  6. Unscrew the regulator from the zero air calibration cylinder.
  7. Leave the sample tubing connected to the regulator and the calibration cup.

Setting the Response Reading

  1. Screw the regulator into the calibration cylinder. Verify that the calibration gas is representative of the transmitter’s target gas.
  2. Turn the regulator’s on/off knob counterclockwise to open the regulator.
  3. Allow the calibration gas to flow for one minute and verify that the reading matches the response reading (±2 mV) you determined earlier. If necessary, use the span pot on the amplifier to adjust the reading to match the correct response reading.
  4. Turn the regulator’s on/off knob clockwise to close the regulator.
  5. Unscrew the regulator from the calibration cylinder.

Returning to Normal Operation

  1. Remove the voltmeter leads from the amplifier test points.
  2. Unscrew the calibration cup from the detector.
    • NOTE: For convenience, leave the regulator and calibration cup connected by the sample tubing.
  3. Secure the junction box cover to the junction box.
  4. When the controller display reading falls below the alarm setpoints, return the controller to normal operation.
  5. Verify that the controller display reading decreases and stabilizes at a typical background CO2 level. The 0-5,000 ppm, 0-9,000 ppm, and 0-5% volume detectors will display a reading in a fresh air environment because they have low ranges. The 0-20% volume, 0-50% volume, and 0- 100% volume detectors will not display a reading in fresh air because their ranges are too large.
  6. Store the components of the calibration kit in a safe and convenient place.

Parts List

Table 7 lists replacement parts and accessories for the CO2 transmitter.

Table 7: Parts List

Part Number Description
06-1248RK Sample tubing (3/16 in. x 5/16 in.; specify length when ordering)
07-0039RK Detector housing cap gasket
18-0400RK-01 Junction box with spacers (for amplifier and detector junction

boxes)
57-1053RK| Amplifier with gasket (specify detector part number when ordering)
61-0191RK-01| Infrared CO2 detector, 0-9,000 ppm
61-0191RK-02| Infrared CO2 detector, 0-5,000 ppm
61-0191RK-03| Infrared CO2 detector, 0-5% Volume
61-0191RK-04| Infrared CO2 detector, 0-20% Volume
61-0191RK-05| Infrared CO2 detector, 0-50% Volume
61-0191RK-10| Infrared CO2 detector, 0-100% Volume
65-2396RK-01| Infrared CO2 transmitter, 0-9,000 ppm (includes detector, junction box, and amplifier)
65-2396RK-02| Infrared CO2 transmitter, 0-5,000 ppm (includes detector, junction box, and amplifier)
65-2396RK-03| Infrared CO2 transmitter, 0-5% Volume (includes detector, junction box, and amplifier)
65-2396RK-04| Infrared CO2 transmitter, 0-20% Volume (includes detector, junction box, and amplifier)
65-2396RK-05| Infrared CO2 transmitter, 0-50% Volume (includes detector, junction box, and amplifier)
65-2396RK-10| Infrared CO2 transmitter, 0-100% Volume (includes detector, junction box, and amplifier)
71-0656| 65-2396RK-XX-04 CO 2 Transmitter Operator’s Manual (this document)
81-0070RK-01| Calibration cylinder, 2000 ppm CO2, 34 liter steel
81-0071RK-01| Calibration cylinder, 5000 ppm CO2, 34 liter steel
81-0071RK-03| Calibration cylinder, 5000 ppm CO2, 34 liter steel
81-0072RK-01| Calibration cylinder, 2.5% CO2, 34 liter steel
Part Number| Description
---|---
81-0073RK-01| Calibration cylinder, 15% CO2, 34 liter steel
81-0078RK-01| Calibration cylinder, 100% nitrogen, 34 liter steel
81-1050RK| Regulator, with gauge and knob, 0.5 liter/minute continuous flow, for 17-liter and 34-liter steel calibration cylinders (cylinders with external threads)
81-1051RK| Regulator, with gauge and knob, 0.5 liter/minute continuous flow, for 34-liter aluminum/58 liter/103-liter calibration cylinders (cylinders with internal threads)
81-1103RK-01| Calibration cup/splash guard
82-0006RK| Pot adjust screwdriver, for calibration

RKI Instruments, Inc.www.rkiinstruments.com

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