FAQ
The ChemLogic® CL1 (1-point) and CL2 (2-point) are continuous gas detection systems designed to monitor toxic, corrosive, and asphyxiant gases for process monitoring and personnel safety. They continuously sample air from remote locations and provide real-time concentration readings, alarms, and output signals to external systems.
The CL1 draws a gas sample across a ChemLogic® paper tape. When the target gas is present, the tape changes color. An optical system measures this color change and converts it into a gas concentration reading.
The CL1 displays the gas concentration, activates visual alarms, triggers relays or analog outputs, and records the alarm data to removable storage.
The CL1 is a single-point continuous gas detector, while the CL2 is a dual-point detector capable of monitoring two sampling locations simultaneously using the same ChemLogic® colorimetric technology
The CL1/CL2 uses colorimetric tape (ChemLogic® Cassette) technology combined with an optical detection system. When target gas contacts the tape, the tape changes color. The optics measure this change and convert it into a precise gas concentration reading which provides interference-free, low-maintenance, and highly reliable detection of low-level toxic and corrosive gases.
It is a continuous monitoring system. When operating in normal analysis mode, the unit continuously samples air, updates concentration readings, and activates alarms when thresholds are exceeded.
The CL1/CL2 supports a wide range of gases, Click here for gas list.
No. The CL1/ CL2 can only have one tape type installed. In result can detect only one gas type.
With the optional Z-Purge enclosure, the CL1 and CL2 can be installed in Class I, Division 1 hazardous locations
FEP tubing, 1/4" OD x 1/8" ID only. Using any other tubing may cause measurement errors or system damage
Up to 150 feet (45 meters). Shorter sample lines improve response time.
Monitoring Diisocyanates gasses the maximum is 6 inches.
Dirty filters or tubing can: dod
Slow gas response
Reduce accuracy
Cause sample loss
Lead to internal system damage
Up to 150 ft (45 m) using ¼” OD Teflon FEP tubing for most gases.
Maximum 6 inches of sample tubing for diisocyanate applications due to their reactive nature
Input voltage: 100 – 260VAC (50/60Hz). Power consumption: Less than 1 Amp
The CL1 comes standard with built in AC Power Cord. Optional configuration for hardwire connection is available.
Yes. The CL1/CL2 is designed for secure wall mounting using the mounting pattern shown in the manual.
Operating temperature: 40°F to 104°F (4°C to 40°C)
Enclosure rating: NEMA 4X for industrial and outdoor environments
The CL1/CL2 provides: Alarm Level 1 and Alarm Level 2. These are factory-set (typically at 1× and 2× TLV) but are user adjustable.
When an alarm level is exceeded:
The display flashes alarm indicators
Alarm relays activate
4-20 mA output reflects the gas concentration
Alarm events are logged to internal memory and SD card
Red: Gas Alarm
Orange: Service Fault
Yellow: Minor Fault
Blue: Information Message
Green: Status Update
This is configurable in the setup menu.
Latching: alarm stays active until acknowledged
Non-latching: alarm clears automatically when gas drops below threshold
The system fault relay is energized during normal operation and de-energized when a fault occurs.
The standard outputs include: Alarm Level 1 relay, Alarm Level 2 relay, System fault relay, 4-20 mA analog output, Remote alarm/fault reset input
Optional outputs include: Modbus/TCP, Modbus/ RS485, Ethernet/ IP
No. The main menu is always accessible for normal operation.
Setup Menu: optional password
Service Menu: password protected by default
Passwords can be changed or disabled by authorized users.
Cassette Saver Mode reduces cassette advancement during gas events to extend cassette life. Modes include: Fixed Cycle, Single Reading, Continuous
⚠️ Important: When Cassette Saver Mode is active, true continuous analysis may be paused, and displayed concentrations may not update in real time.
“TSM” appears on the analysis screen
A blinking countdown indicates no active analysis during that period
Gas concentration logs, Alarm and fault history, Event logs, Configuration data, TWA data (where applicable)
An SD card is not required for operation but is required for data logging and historical record retention.
Micro SD / TransFlash
Up to 2 GB
Must be formatted FAT16
FAT32 cards will not work
Yes. The SD card slot supports hot insertion and removal.
Yes. The CL1/CL2 include an SD memory card for easy retrieval of historical gas detection data and event logs
DAC represents the LED light intensity used by the optics system. It indicates the cleanliness and transparency of the optic path.
A clean, properly operating CL1 typically has a DAC value between 70 and 120.
This warning appears when the DAC reaches 140, indicating the optics should be cleaned soon. It does not trigger the fault relay.
This fault occurs at a DAC value of 150. The CL1 will stop analysis until the optics are cleaned and recalibrated.
Cleaning is recommended when the DAC value approaches 130 or when optics-related faults occur.
This is typically caused by loss of 5 VDC power to the optics, a faulty communication cable, or a failed HMI communication port.
The flow system includes two sample pumps, an upper filter/orifice assembly, a pressure differential transducer, and the HMI.
Pump voltage (P): typically between 1600 and 3200
These faults usually indicate a clogged optic orifice or a pressure transducer offset issue.
Common causes include leaks in the flow path, clogged filters, or worn/weak sample pumps.
Sample pumps generally last 3–5 years under normal operating conditions.
The CL1 automatically disables the failed pump and continues operation using the remaining pump. No fault is generated, but a P1 or P2 indicator appears on the display.
Yes. Each cassette is specific to a particular gas and must match the gas selected in the CL1 setup.
No. The cassette must be within its expiration date to ensure accurate detection.
Approximately 0.30 inches (7.6 mm) per advance.
These faults occur when the tape advance mechanism does not properly change the microswitch state during the gate open or close sequence.
The ChemLogic CLPx is a portable colorimetric gas monitor designed to measure low concentrations of a specific toxic gas or a related range of toxic gases or vapors. It is intended to be used as part of an air quality management program. The monitor uses ChemLogic colorimetric technology, where the tape darkens in the presence of target gas and the instrument’s optics measure that change to determine concentration.
During analysis, the pump pulls a measured sample of air through the chemically-treated tape in a ChemLogic cassette. If the target gas is present, the tape stains or darkens. The instrument’s optics then measure the difference between the tape’s original color and the stained area. The CLPx converts that optical change into a gas concentration reading and stores the results internally; and, if installed, on the MicroSD card in CSV format.
The CLPx is not a multi-gas monitor in the same sense as a 4-gas personal monitor. It is designed to measure a specific gas or a specific range of related gases/vapors, depending on the gas family and cassette configuration installed at the factory. Gas options available depend on what was purchased and how the unit is configured.
The CLPx is powered by a 6-volt rechargeable lead-acid battery.
No. You should only use the charger supplied with the CLPx. Using a different charger could damage the battery and/or the instrument.
No. The battery charger has not been evaluated for intrinsic safety and must not be used in a potentially explosive atmosphere. Using the charger or CLPx in a flammable or explosive atmosphere could ignite the atmosphere and cause serious injury or death.
Yes, it is recommended to keep the battery at float charge when the unit is not in use. This helps extend battery life and keeps the monitor ready for use.
Yes. To replace the battery, disconnect the charger, make sure the unit is off, work in a clean non-hazardous area, remove the four battery screws with a 9/64 in. (3.5 mm) Allen wrench, disconnect the two-pin connector, and reinstall in reverse order. Battery removal must never be performed in a potentially explosive atmosphere.
To power the unit on, press the Enter button.
An asterisk in the lower-right corner indicates the monitor has passed the time necessary to detect the LDL for the selected gas since the last cassette advance. The asterisk disappears and the timer resets whenever the cassette advances. The operator can also press the down arrow to reset the timer when checking a new location.
The letters SD appearing on the upper-left of the analysis screen indicate there is an error writing to the MicroSD card or that no MicroSD card is inserted.
The CLPx automatically calculates STEL for the selected gas. A STEL log is stored in the instrument, and if a properly formatted MicroSD card is installed, STEL details are also written to the card. The monitor keeps at least 16 STEL values depending on memory usage.
The Verify Tape screen shows the currently selected gas and the ChemLogic cassette that should be installed. It is a quick way to confirm that the correct cassette is in the instrument before sampling.
The MicroSD card stores: Concentration logging, Event history, STEL history, and Configuration information. The SD Card screen also shows remaining free space, this should be checked before use to make sure there is enough room for logging.
No. The manual says to power the machine down first before inserting or removing the MicroSD card, otherwise data may be lost or the card may become corrupted.
Standard MicroSD cards may be used with FAT16 or FAT32 formatting.
When viewing the unit from the back, install the card with the 8-pin gold edge connector facing to the left.
The Memory Flash Error can occur due to no SD card installed, SD card full or Card write error. First checks should be whether the MicroSD card is present, has free space, is properly formatted, and is functioning normally.
If the concentration exceeds either the low or high alarm setpoint, the monitor will sound an alarm and flash the concentration level. During analysis: Alarm Level 1 blinks at a 2-second rate and Alarm Level 2 blinks at a 1-second rate. The default alarm values are normally set to 1 TLV and 2 TLV when a gas is selected, though they can be adjusted.
Yes. In Setup > Set Alarm Levels, the alarm levels can be adjusted as needed. The manual says to be sure to select Save after making changes.
Yes. The History screen stores recent events even if there is no SD card installed. The manual says at least 16 events are kept at all times, often more depending on memory use. The most recent event appears first, and you can scroll through events and use the right key to see more details and diagnostic codes.
The sampling wand lets the operator sample gas farther away from the unit, such as around gas cylinders or fittings when leak checking. The sampling wand will come with 5 feet of tubing that can be connected to the inlet.
The exhaust option adds an external exhaust port so sample gas can be routed through tubing to an exhaust hood or similar safe discharge point.
Go to Setup > Adjust Flow, connect the included flow meter, and adjust the pump until the displayed target flow is reached. A ChemLogic tape cassette must be installed while adjusting flow.
Yes. The target flow depends on the cassette and gas being used. For example, some gases use 200 cc, while others use 120 cc. That means flow should always be set according to the configured gas/cassette combination rather than assuming one universal value.
This is the recommended quick method to verify optics adjustment and light intensity. The manual notes the tape reading will be approximately 2800 during this test.
Optic calibration faults can occur due to dirty optics, no cassette installed or if you reach the end of the cassette. Verify the correct cassette is installed, check whether the tape is spent, and clean the unit if needed. If the issue remains, contact DOD support.
The Cal Stick Test is not used to calibrate the optics, since the optics self-calibrate, but it does verify that the optics can properly adjust and detect color change. The manual recommends running an Auto Optics Test after using the Cal Stick.
Click here for full list of gases:
CLPx Detectable Gas List (Build 991 & Above) -or- CLPx Detectable Gas List (Build 990 & Below)
Go to Setup > Select Gas. The available selections are based on the gas family installed at the factory. When you choose a gas, the CLPx loads default alarm levels and gives you the option to go directly to the alarm setting screen.
Open the cassette access door by turning the cassette release knob fully to the left. Remove the black tape guide, place the cassette inside with the label upright and facing outward, and make sure the tape sits properly between the optics block and the inlet nosepiece before closing the door and turning the knob closed.
The expiration date of all cassettes is printed on the label of each cassette. However, once the package is opened the maximum number of days the cassette can be used without proper storage is within 45 days. After each use, if the cassette is put back into its original packaging and stored at the proper temperature, it may be used up to the original printed expiration date.
Tape Advance Err1 and Tape Advance Err2 may be caused by a tape jam or low voltage. That means the operator should check battery condition, confirm tape path and cassette seating, and inspect for tape issues or jams.
Use Setup > System Info. This displays software version, serial number, and selected gas. For version 12.3 and higher, it also shows the installer/updater version.
ILA QA