Watchgas TOX Point 1000 User Manual
1. GENERAL
The TOX Point 1000 toxic gas detector is designed to detect gas leaks from industrial sites and various toxic gases generated in factories, gas storages, and manufacturing processes. It helps prevent accidents by detecting leaks of toxic gases. The TOX Point 1000 is installed in areas with gas leak hazards and continuously monitors for leaks. It converts and transmits data using a DC 4~20 mA standard output signal. For this output, the signal transmission length between the detector and receiver can be up to 2,000 meters when using Cable CVVS or CVVSB 1.5 sq or higher.
2. CONFIGURATION
The body of the TOX Point 1000 is constructed from Aluminum alloy, and the gas sensor module is made of stainless steel. It features a complete explosion-proof enclosure (Ex d IIC T6), making it suitable for areas with potential combustible gas leaks and explosion hazards. Internally, it comprises a single PCB board with a display for measurements and a terminal part for external output of measurements (DC 4-20 mA). The external configuration includes the detector part for monitoring gas leaks and cable inlets.
Figure 1. TOX Point 1000 Overview
Diagram showing the TOX Point 1000 Gas Detector in a Hazardous Area, connected to a Transmitter enclosure containing the Gas Sensor Module and Main Board. It illustrates the power input (+24V DC) and 4-20mA Analog Signal Output to a Safety Power Supply Unit and Safety Controller in a Safe Area. Includes a legend for signal lines.
3. SPECIFICATIONS
3.1. BASIC SPECIFICATIONS
| Items | Specification |
|---|---|
| Measuring Type | Diffusion |
| Measuring Method | Electrochemical Cell, Heated-semiconductor Cell |
| Detectible Gas | Toxic Gas (Note 1) |
| Measuring Range | 000.0 ~ 9999 (Note1) |
| Accuracy | ≤ ±3% / Full Range |
| Zero Drift | ≤ 2% / Full Range |
| Response Time | Depends on Sensor Module. Refer to Sensor Specification or Contact in case for Special Gas. |
| Approvals Classification | KCs: Ex d IIC T6 |
| Basic Interface | Analog 4-20mA current interface |
| Option | Rain Cover |
| Warranty | Transmitter: 2 Year, Sensor: 1 Year |
Note1: Refer to the measured gas list for measured gases and their ranges. Contact Watchgas for special gas.
3.2. MECHANICAL SPECIFICATIONS
| Items | Specification |
|---|---|
| Explosion Proof type | Explosion-Proof Enclosure |
| Dimension | 136(W) × 166(H) × 95(D) mm |
| Weight including Sensor | App. 1.5kg |
| Mounting type | Wall mount |
| Mounting Holes | Ø 7 ±0.1 |
| Cable inlet | 3/4" PF (1/2" or 3/4" NPT) |
| Body material | Transmitter: Aluminum alloy, Sensor: Stainless Steel (STS316) |
3.3. ELECTRICAL SPECIFICATIONS (STANDARD TYPE)
| Items | Specification |
|---|---|
| Input Voltage (Standard) ※ Customer supplied PSU must meet requirements IEC1010-1 and CE Marking requirements. | Absolute min: 16V Nominal: 24V Absolute max: 31V Ripple maximum allowed: 1V pk-pk |
| Wattage | Max. wattage: 0.5W @+24 VDC Max. current: 22mA @+24 VDC |
| Analog output Current | 0-20mA (500 ohms max load) All readings ± 0.2mA Measured-value signal: 4mA (Zero) to 20mA (Full Scale) Fault: 0mA 0-100% LEL: 4mA - 20mA 100-109%LEL: 21.6mA Over 110% LEL: 20mA - 21.4mA Maintenance: 3mA |
| Analog output current ripple & noise max | ±20uA |
| Wiring requirement | Power: CVVS or CVVSB with shield Analog: CVVS or CVVSB with shield |
| Cable Connection Length | Analog: 2500m |
| EMC Protection: | Complies with EN50270 |
3.4. ENVIRONMENTAL SPECIFICATIONS
| Items | Specification |
|---|---|
| Operation Temperature | Transmitter: -20 to 50 °C Sensor: Refer to Sensor Specification |
| Storage Temperature | Transmitter: -20 to 50 °C Sensor: Refer to Sensor Specification |
| Operation Humidity | Transmitter: 5 to 99% RH (Non-condensing) Sensor: Refer to Sensor Specification |
| Pressure Range | 90 to 110KPa |
| Max. air velocity | 6m/s |
4. NAME AND DESCRIPTION OF EACH PART
4.1. COMPONENTS
The TOX Point 2000 Gas Detector has several key components:
Figure 2. Tox Point 2000 Components
Illustration of the TOX Point 2000 components, with numbered parts corresponding to Table 1: Detector Housing Body, Detector Housing Cover, Sensor head, Internal ground, External ground, Conduit connection, Mount holes, Sensor terminal, and Model name plate.
| No | Items | Specification |
|---|---|---|
| 1 | Detector Housing Body | Protects the PCB board within the Sensor and Housing from external environmental changes and shock. |
| 2 | Detector Housing Cover | Assembled with the detector housing body, it protects the PCB board within the Sensor and Housing from external environmental changes and shock. |
| 3 | Sensor head | Detects actual gas leaks, converting the amount of gas leak into an electrical signal and transmitting it to the Amp PCB. |
| 4 | Internal ground (2 sq↑ cable) | Must be grounded to the inside of the detector for protection from external noise or strong electric fields. |
| 5 | External ground (2 sq↑ cable) | Must be grounded to the outside of the detector for protection from external noise or strong electric fields. |
| 6 | Conduit connection | Supplied for inlet of power supply and measurement output signal for the detector during installation. Cable inlet options include PF or NPT 1/2", 3/4" (Default specification is PF 3/4"). |
| 7 | Mount holes (Ø 7 ±0.1) | Holes to fix the gas detector onto an external wall or other installation sites. |
| 8 | Sensor terminal | CN1 serves as the Sensor Connection Terminal. |
| 9 | Model name plate | The model name, measuring gas, serial number, etc., are labeled here. |
5. INSTALLATION
Installation and repair of the gas leak sensor are prohibited for individuals other than approved users or technicians from the head office. Opening the cover of an installed gas leak sensor and manipulating it can lead to serious loss of life and property due to fire, explosion, etc. Before commencing work, ensure there is no remaining explosive gas or combustible material in the surroundings. Power must be turned off.
5.1. DETACHMENT OF HOUSING COVER
To detach the housing cover:
- Turn the slotted set screw (M4 x 1ea) approximately 3-4 turns counter-clockwise (ccw) using a hex wrench (M2). This releases the cover part of the main body.
- Then, turn the cover of the gas leak detector counter-clockwise (ccw) to detach it.
Figure 3. Slotted Set Screw
Close-up illustration of the slotted set screw (M4 x 1ea) used to secure the housing cover, indicating the need for a hex wrench (M2) for removal.
5.2. MAIN PCB CONFIGURATION
After detaching the display parts, the Main PCB terminal layout is visible as shown in the figure below.
Figure 4. Main PCB Key Layout
Diagram of the Main PCB layout, showing connectors (CN3, CN5), switches (SW1, SW3, SW4, SW5, SW6), potentiometers (VR1, VR2), and display (FND1,2). Components are numbered and described in Table 2.
| No | Name | Description |
|---|---|---|
| 1 | CN3 | Program download Connector |
| 2 | SW5 | Zero Calibration Switch |
| 3 | SW6 | Span Calibration Switch |
| 4 | SW1 | Sensor Configuration Switch 1 (Factory Setting) |
| 5 | VR1 | Potentiometer for ZERO Output Adjustment |
| 6 | VR2 | Potentiometer for SPAN Output Adjustment |
| 7 | SW4 | Sensor Configuration Switch 2 (Factory Setting) |
| 8 | SW3 | Mode Control DIP Switch |
| 9 | CN5 | Power & Output Signal Terminal |
| 10 | FND1,2 | FND for Internal Status Display |
5.3. POWER AND SIGNAL TERMINAL CONFIGURATION
After disassembling the display parts, a terminal block is present on the Main PCB. Hold the terminal block and pull upwards to detach it from the Main PCB.
Loosen the 5 terminal fixing screws located at the top of the detached terminal block CN8 (VIS, +, mA, -, ETH) by turning them counter-clockwise using a screwdriver. Connect the DC 18~24 V power to the '+' and '-' terminals, then connect the signal cable to the 'mA' terminal. Tighten the 5 terminal fixing screws clockwise to secure the terminal, ensuring it does not leave its track. Reinsert the Main PCB in the same condition as before disassembly.
Figure 5. CN1 Terminal Configuration
Illustration of the CN1 Terminal Configuration, detailing the connections for Power (+24V/POWER (+)), 4-20mA Source Out (mA), Ground (GND/Power (-)), and Earth (ET).
| No | Pin Name | Description |
|---|---|---|
| 1 | + | +24V / POWER (+) |
| 2 | mA | 4~20mA Source Out |
| 3 | - | GND / Power (-) |
| 4 | ET | EARTH |
Use CVVS or CVVSB 2.0 sq↑ Shield Cable for terminal configuration.
5.4. METHOD TO CONNECT TO EXTERNAL CONTROL UNIT
Connect the 18 V~31 V DC operation power to the CN1 (+, mA, -, ET) Connection Terminal of the gas detector. Then, connect a device capable of receiving 4~20 mA signals to the 'mA' terminal.
Figure 6. External Control Unit Connection Method
Diagram illustrating the connection method between the Gas Detector and an External Control Unit. It shows power (+24V DC) and signal (4-20mA) lines connecting from the detector's CN1 terminal to the control unit.
5.5. INSTALLATION CABLE LENGTH
The maximum installation length between the GTD-1000Tx and the power supply is determined by wire specifications.
The formula for maximum installation length is: Max. Installation Length = VMAXDROP ÷ IMAX ÷ WIRER/m ÷ 2
- VMAXDROP: Maximum Power Loop Voltage Drop (Power Supply voltage - minimum operating voltage).
- IMAX: Maximum Current of the TOX Point 1000.
- WIRER/m: The resistance of the wire in ohms per meter (value available in the wire manufacturer's specification data sheet).
Example calculation for installation lengths using a 24 V power supply and 16 AWG wire:
- TOX Point 1000 minimum operating voltage = 18 Vdc
- VMAXDROP = 24V - 18V = 6V
- IMAX = 0.15A (150mA)
- Using a WIRER/m value of 0.01318 ohms/meter for 16 AWG wire:
- Max. Installation Length = 6V / 0.15A / 0.01318 ohms/m / 2 = 1517.451 meters (approximately 1517 meters).
Figure 7. Calculation of TOX Point 1000 Installation Cable Length
Visual representation of the calculation for maximum installation cable length, demonstrating voltage drop (VMAXDROP), maximum current (IMAX), and wire resistance (WIRER/m) for the TOX Point 1000 with a 24V power supply and 16 AWG cable.
Power cable installation for each cable type is detailed in the table below:
| AWG | mm² | Copper Resistance (ohms/m) | Meters |
|---|---|---|---|
| 12 | 3.31 | 0.00521 | 3838 |
| 14 | 2.08 | 0.00828 | 2415 |
| 16 | 1.31 | 0.01318 | 1517 |
| 18 | 0.82 | 0.02095 | 954 |
| 20 | 0.518 | 0.0333 | 600 |
Table 4. GTD-1000Tx Power Cable Installation Length
A stabilization time of 30 minutes is required from the initial supply of operation power to the sensor for stabilization. Calibration and testing should be performed approximately 30 minutes after the sensor has stabilized.
6. CALIBRATION AND MAINTENANCE
6.1. 4-20mA OUTPUT DIAGNOSIS
The unit supplies 18~31 V and 200 mA current to the sensor. The 4~20 mA current output can be confirmed by measuring the voltage between TP5 (+mA) and TP6 (-mA) of the AMP PCB using a multimeter.
Figure 8. 4-20mA Output Test Terminal
Diagram showing the location of test points TP5 and TP6 on the AMP PCB for measuring the 4-20mA output signal.
6.2. 4mA ADJUSTMENT (ZERO CALIBRATION)
- Check the voltage of 18~31 V DC at both the (+24 V) and (GND) terminals of the terminal block 'CN5'.
- Verify that the (mA) terminal of terminal block 'CN5' is connected to the receiver.
- Set a Digital Multimeter (DMM) to current measuring mode. Connect the DMM's (+) and (-) terminals to TP5 (+mA) and TP6 (-mA) of the AMP PCB, respectively.
- Press the zero switch (SW5) for 3 seconds. The message "[ZE][RO]" will flash three times on FND1 and FND2, indicating entry into zero calibration mode.
- When clean air or 99.9% nitrogen (N2) is injected into the cell part, a 4 mA output should be observed. If the output is not 4 mA, adjust the potentiometer 'VR2 (ZERO)' by turning it left or right to set the output to 4 mA.
- After setting the output to 4.00 mA, press the zero switch (SW5) again for 3 seconds. The result of the zero calibration will be displayed on FND1 and FND2. "[PA][SS]" indicates successful calibration, while "[FA][IL]" indicates failure. In case of failure, reconfirm the sensor and power connections, then repeat the calibration.
Figure 9. ZERO Calibration related Parts
Diagram highlighting components relevant to ZERO calibration: Zero Cal. Switch (SW5) and Zero Cal. Potentiometer (VR2) on the Main PCB.
6.3. SPAN CALIBRATION
- Check the voltage of 18~31 V DC at both the (+24 V) and (GND) terminals of the terminal block 'CN5'.
- Verify that the (mA) terminal of terminal block 'CN5' is connected to the receiver.
- Set a Digital Multimeter (DMM) to current measuring mode. Connect the DMM's (+) and (-) terminals to TP5 (+mA) and TP6 (-mA) of the AMP PCB, respectively.
- Press the span switch (SW6) for 3 seconds. The message "[SP][AN]" will flash three times on FND1 and FND2, indicating entry into span calibration mode.
- When the standard calibration gas is injected into the cell part, a 12 mA output should be observed. If the output is not 12 mA, adjust the potentiometer 'VR3 (SPAN)' by turning it left or right to set the output to 12 mA.
- Adjust the 'SPAN' potentiometer to achieve the correct current output for the standard gas, which should be displayed on FND1 and FND2.
- When the span switch (SW6) is pressed for 4 seconds after setting the desired output, the result of the span calibration will be displayed on FND1 and FND2. "[PA][SS]" indicates successful calibration, while "[FA][IL]" indicates failure. In case of failure, reconfirm the sensor and power connections, then repeat the calibration.
Figure 10. Span Calibration related Parts
Diagram highlighting components relevant to SPAN calibration: Span Cal. Switch (SW6) and Span Cal. Potentiometer (VR3) on the Main PCB.
7. DRAWINGS AND DIMENSIONS
The document provides examples for output calculation methods for NH3 and CO. For NH3 (Range: 0-150ppm, Output signal: 4-20mA), using 100ppm NH3 as standard gas, the calculation is (200-40) × (100ppm NH3 / 150ppm NH3) + 40 = 14.7 mA. For CO (Range: 0-150ppm, Output signal: 4-20mA), using 100ppm CO as standard gas, the calculation is (200-40) × (100ppm CO / 150ppm CO) + 40 = 14.7 mA.
Figure 11. TOX Point 1000 Drawing
Mechanical drawings and dimensions of the TOX Point 1000, showing front and side views with key measurements such as height (166 mm), width (136 mm), and depth (95 mm).
8. PRECAUTIONS BEFORE INSTALLATION
8.1. SELECTING A PLACE FOR INSTALLATION (OCCUPATIONAL HEALTH & SAFETY ACT DATA)
A gas leak detector alarm should be installed in the following locations:
- Around chemical equipment and accessories that may have gas leaks, including compressors, valves, reactors, and pipe joints, both inside and outside buildings handling combustible and toxic materials.
- In areas where gases are likely to accumulate, such as around manufacturing facilities with ignition sources like heating furnaces.
- In areas around equipment used for filling combustible and toxic materials.
- Substations, panel rooms, control rooms, and other locations within explosive areas.
- Other areas where gases are prone to accumulation.
8.2. SELECTING A SITE FOR INSTALLATION (HIGH-PRESSURE GAS SAFETY CONTROL ACT DATA)
Gas leak detector alarms must be installed as close as possible to areas with potential gas leakage. However, in areas where direct leakage is not expected but leaked gas might accumulate, the detector should be installed at the following points:
- For outdoor installations, position the alarm where gas is likely to stay, considering wind direction, wind speed, and the specific gravity of the gas.
- For indoor installations, place the alarm near the floor if the gas is heavier than air, or near ceiling ventilation if the gas is lighter than air.
- Alarms must be installed at sites where the gas detector is located and where workers are present.
8.3. PRECAUTIONS DURING INSTALLATION
Avoid areas with electrical barriers such as exposure to rainwater. It is recommended to install in areas that are easily accessible for regular maintenance. Avoid areas with vibration or shock, as these can affect output values. The sensor part must be installed facing the direction of gravity.
- This equipment features explosion-proof construction for internal pressure and belongs to GROUP II for gas and vapor in general work sites and chemical plants. It can be used in ZONE 1 (ONE) and ZONE 2 (TWO) hazardous sites.
- The allowable temperature is 85 °C or below, corresponding to T6.
- Use within a surrounding temperature range of -20 °C to 50 °C.
- Installation Height: 1,000 M below sea level.
- Relative Humidity: 5% ~ 99%.
- Installation Site: Indoor and Outdoor.
- Explosion Ignition Group for Target Gas or Vapor: Ex d IIC T6.
- During wiring, use explosion-proof cable glands at cable inlets or tightly seal cable conduits during metal cable wiring construction to prevent flame spread in case of explosion or gas movement through the conduit (within 50 mm).
- When connecting the equipment with cable, ensure the screw thread is tightened 5 threads or more.
- Work must comply with other relevant standards, such as [Standards for Selection, Installation, and Maintenance, etc. of Explosion-proof Electric Machine and Equipment Wiring, etc. at Work Site].
- All materials used for cable inlets, such as cable glands and sealing fittings, must pass verification, especially for unused inlets.
Figure 12. High-Pressure Packing Type
Illustration of the High-Pressure Packing Type for cable entry, detailing the arrangement of sealing rings, washers, and connectors.
Figure 13. Y Sealing Compound
Illustration of the Y Sealing Compound method for cable entry, showing the charging compound and cable-fixing device.
9. REVISION HISTORY
| VERSION | CONTENTS | DATE |
|---|---|---|
| 1.0 | * Manual Initial Revision | 28.07.2025 |
