Gas Detection at Well Sites and Stations: Fixed, Portable 4-Gas or Leak Finder?
Short answer: Gas detection comes in three jobs. A fixed detector watches one area all the time and sends its reading to a PLC or alarm panel. A portable 4-gas monitor goes with the person. A handheld leak finder checks joints and fittings for combustible gas. AutomationBotX sells one of each, with the specs below taken from the listings. Read the safety note first: none of these units comes with a hazardous-area or personal-monitor certificate.
Safety note
None of these listings includes an ATEX, IECEx, UL or Class/Division certificate. The portable 4-gas monitor is listed by its supplier as civilian grade. Where your site, your client or a regulator requires certified gas detection (for example for H2S at a wellhead, for confined-space entry or as a crew’s personal monitor), use a certified instrument. The units below are suitable as additional, non-certified monitoring and leak checking, not as a replacement for required safety equipment.
Which one do I need?
| Job | Unit | What it does (per the listing) | Price (USD) |
|---|---|---|---|
| Watch one area all the time and send the reading to a PLC, RTU or alarm panel | Fixed single-gas detector | One gas per unit, chosen as a variant; 4-20 mA and RS485 outputs | from $279.99 |
| See four gases at once while working, with alarms on the person | Portable 4-gas detector | LEL, H2S, CO and O2 together; sound, light and vibration alarms; rechargeable | $100.99 |
| Find a combustible gas leak at a joint, valve or regulator | CGD02A handheld leak detector | 0-100 % LEL / 50,000 ppm; LCD; sound and light alarm | $144.99 |
Prices as listed on 6 November 2026; the product page always shows the current price for each variant.
Specs side by side
| Fixed single-gas detector | Portable 4-gas detector | CGD02A leak detector | |
|---|---|---|---|
| Store SKU | ABX-AE-190158 | ABX-AE-876788 | ABX-AE-721027 |
| Gases and ranges | Choose one: CH4 0-100 % LEL, combustible 0-100 % LEL, H2S 0-100 ppm, CO 0-500 ppm or O2 0-30 % vol | LEL 0-100 %, H2S 0-100 ppm, CO 0-1000 ppm, O2 0-30 % vol | Combustible gas 0-100 % LEL / 50,000 ppm |
| Alarm set points | At the PLC or panel that reads the signal | LEL 20/50 %, H2S 10/35 ppm, CO 50/150 ppm, O2 19.5/23.5 % (adjustable) | Sound and light alarm |
| Output | 4-20 mA + RS485 | Local alarms only | LCD and local alarm |
| Power | Fixed installation | 1800 mAh rechargeable battery | Battery not included |
| Listed accuracy / response | Not stated in the listing | ≤ ±5 % F.S.; T < 30 s | Not stated in the listing |
| Certification | None included | None included; civilian grade per supplier | None included |
Questions and answers
Can the fixed detector trigger a shutdown or a horn?
The detector sends a 4-20 mA and RS485 signal. Your PLC, RTU or alarm panel compares it with your set points and drives the horn, beacon or shutdown. Set and test that logic yourself.
How do I check that the portable monitor works?
The listing asks for a bump test with a known gas before each use and calibration on a regular schedule. It has zero and span calibration functions and is supplied factory calibrated, according to the supplier.
Can I use the CGD02A to clear a confined space for entry?
No. It is a combustible leak finder. Confined-space entry needs oxygen, H2S, CO and LEL readings from an instrument your safety program accepts.
Buy
- Fixed single-gas detector, 4-20 mA + RS485, from $279.99
- Portable 4-gas detector (LEL, H2S, CO, O2), $100.99
- CGD02A combustible gas leak detector, $144.99
Free US shipping on every order. Specs above come from the product listings; if a value you need is not listed, it is not stated by the supplier.