CH₄
Methane
- 0–5000 ppm±10 ppm below 500; ±2 % above
- 0–100 %vol±0.05 %vol below 1 %vol; ±3 % above
Supplied and adapted by Specvaltech · Instrument integration
Box-level Extractive TDLAS Gas Measurement Module
This module goes inside your instrument. It is a 140 × 110 × 96 mm box running on 12 V at up to 3 W, with two stainless steel fittings for sample in and sample out, and a configured RS232, RS485 or 4–20 mA output to your controller.
Standard Gases
CH₄ / CO₂ / CO / NH₃
Four gases, each with its own accuracy figure per range.
Supply & Power
DC 12 V · ≤3 W
Steady state; no intrinsic safety rating.
Dimensions
140×110×96 mm
Matte black metal enclosure for installation inside an instrument.
Output
RS232 / RS485 / 4–20 mA
Configured per project; not all three simultaneously.
Extractive, inside your instrument
Where the module sits, and where you sit
The module is one element in a measurement chain that you own.
Sample gas is drawn from your process by your pump, travels through your line, passes any filter or condensate stage you have fitted, and arrives at the module inlet at a flow you control. The module measures what arrives. It reports a concentration to your controller and returns the gas through the outlet fitting.
It does not take its own sample. The pump, the sample line, the conditioning and the flow control are yours. That boundary is where most disappointments in this kind of integration come from, so it is set out explicitly below.
It measures four standard gases: CH₄, CO₂, CO and NH₃, each with its own accuracy figure per range.
Four standard gases
Accuracy per gas, per range
All figures at 1 L/min, 25 °C, ambient pressure, nitrogen balance, after warm-up. Each gas has its own accuracy figure because the measurement physics differ.
CO₂
Carbon Dioxide
- 0–5000 ppm±10 ppm below 500; ±2 % above
- 0–100 %vol±0.05 %vol below 1 %vol; ±3 % above
CO
Carbon Monoxide
- 0–1000 ppm±3 ppm below 100; ±2.5 % above
- 0–5000 ppm±10 ppm below 500; ±2.5 % above
NH₃
Ammonia
- 0–100 ppm±0.5 ppm below 10; ±3 % above
- 0–1000 ppm±3 ppm below 100; ±3 % above
Why there is no single accuracy figure on this page
A ±1 % of full scale specification was on an earlier version of this datasheet and we withdrew it. Full scale changes by four orders of magnitude between the 0–100 ppm range and the 0–100 %vol range. The same percentage means a completely different absolute error at each end.
Platform specification
Full specification
Figures apply at 1 L/min, 25 °C, 101.3 kPa, nitrogen balance, after warm-up.
| Parameter | Value |
|---|---|
| Standard gases | CH₄, CO₂, CO, NH₃ |
| Sampling | Extractive, external pump. Two stainless steel sample fittings: IN from the conditioned sample line and OUT to the host return/exhaust path |
| Nominal sample flow | 1 L/min at 20 °C and 101.3 kPa |
| Response, T90 | ≤30 s at 1 L/min |
| Accuracy | Segmented, per gas and per range — see table above |
| Supply | DC 12 V |
| Power | ≤3 W steady state |
| Output | RS232, RS485 or 4–20 mA, configured per project; do not assume all three are populated together |
| Operating temperature | 0 to +45 °C |
| Dimensions | 140 × 110 × 96 mm |
| Housing | Matte black metal |
| Ingress protection | Designed to IP40, for installation inside an enclosure — Design objective |
| Explosion protection | None. See “Where this module does not go” below |
When this module fits
Three conditions that confirm a fit
Inside an instrument
The module is designed for installation inside an analyser or detection instrument. The enclosure provides the mechanical protection and the sample conditioning stage.
Sample system already exists
Your instrument already has a pump, a sample line, and a conditioning stage. The module receives conditioned gas at a controlled 1 L/min flow. If the sample system does not exist yet, that is the first thing to design.
One of the four standard gases
CH₄, CO₂, CO or NH₃ at a range that matches the accuracy table above. Other gases are possible as project work but do not share this module’s optical stack.
Limits
Where this module does not go
No mine use — no intrinsic safety
The module runs on 12 V at up to 3 W. The input power envelope for Ex ia I Ma is 0.688 W. A 12 V, 3 W module cannot be made intrinsically safe — this is arithmetic, not a certification we have chosen not to pursue. For a coal mine or any Ex-classified installation, use the Pipeline Insertion module.
Not for direct in-pipe measurement
The module expects conditioned sample gas arriving at a controlled flow. Placing it on a process line without a sample system is outside what it is built for.
Oxygen and other non-standard gases
Oxygen absorbs near 760 nm, which needs a different laser and detector from the four gases above. It is possible as project work, and it does not share this module’s optical stack. → What a multi-gas TDLAS platform can and cannot share
Above +45 °C or below 0 °C
The module is specified for installation inside an enclosure. If your enclosure runs hotter, the operating temperature is a project condition to resolve before anything else.
Delivery boundary
What we deliver, and where responsibility ends
| We deliver | We do not deliver |
|---|---|
| The measurement module, configured to the agreed gas and range | The sample system: pump, line, filter, condensate handling, flow control |
| Calibration data and algorithm firmware | Your instrument’s certification |
| Self-diagnostic output | Host-side application logic, alarms or display |
| Communication protocol stack and integration documentation | On-site installation and field calibration service |
| Bench test report with the test conditions stated | |
| Component traceability documentation |
What we need from you
Target gas and measuring range · Background composition, including moisture · Sample flow you can deliver, and whether it is controlled · Sample conditioning already in your instrument: filter, condensate handling, heating · Enclosure temperature range at the module location · Supply, output interface and host protocol · Physical space and mounting orientation · Whether your instrument carries any certification the module has to fit into.
Items you can answer move into qualification. Items you cannot are recorded as unknown with a way to resolve them. We do not close an unknown with a customisation promise.
Take the Next Step
Send us the gas, the range, the background composition and the interface.
What comes back is one of four things: which structure may fit, what is already confirmed, what still has to be verified, and whether the next step is a technical discussion, a sample test, a quotation, or stopping. If a fit does not exist, that answer usually arrives faster.