Electrochemical Carbon Monoxide Sensor

Electrochemical COppm sensing principle

DC 12～24VTypical supply

RS485Isolated digital output

0～5000 ppmTypical range

Product Overview and Engineering Role

The SimtoLink electrochemical carbon monoxide sensor is for carbon monoxide (CO) at ppm. The cell is electrochemical. That is a different gas, a different unit, and a different cross-sensitivity from the usual carbon dioxide (CO₂) infrared (NDIR) analyzer, so do not mix the copy or the point table when you select. An electrochemical CO cell drifts with cross-sensitivity and with age. Temperature and humidity compensation, a scheduled zero calibration, and a replacement cycle are what keep it inside fire and occupational-health alarm limits. Terminals are pluggable, the communications and power ports are protected and isolated, and the firmware can back up parameters and be maintained remotely.

The interface is isolated RS485, typically with a Modbus RTU point table, into a PLC, a gateway, or SCADA. A wide DC range can be taken from the cabinet bus or from a supply on site. SimtoLink supplies a register description and sample messages. Volume jobs can take enclosure silkscreen, a set harness length, a protocol map, and a calibration certificate. For CO₂ volume concentration or fresh-air energy control, use the dedicated CO₂/NDIR line. Do not apply the figures on this page to CO₂.

Reliability and Site Conditions

On electrical safety and EMC, the sensor has passed the IEC 61000-4 level 4 items that apply. Ports have surge and reverse-polarity protection. A reinforced ground and a partitioned layout keep ground loops and common-mode noise down. Outdoor or coastal sites can take a higher ingress rating and a corrosion-resistant coating.

Parameters can be loaded in batches, thresholds can be set, and event video or waveforms can be stored when the model allows it. OTA carries configuration and firmware. Site acceptance is three checks: a power-on self-test, time alignment on the communications link, and a spot check of samples. For metering or safety duty, SimtoLink helps with submission to a third-party metrology institute and with the type-test file.

Key Hardware Parameters

The table is this sensor in a typical build, for selection and for the technical clauses of a bid. A wider range, redundant power, or an intrinsically safe explosion-proof variant is available from SimtoLink with the Hardware Specification and the Installation and Commissioning Guide. Order codes in the same family can differ slightly; the nameplate and the papers shipped with the unit govern.

Parameter	Specification	Remarks
Sensing principle	Electrochemical	Temperature compensation
Range	0～5000 ppm	Can be calibrated
Resolution	0.1 ppm	Digital output
Repeatability	±3.9 %FS	Constant temperature and humidity
Zero drift	<6.1 ppm/month	Clean air
Supply	DC 12～24V	Reverse-polarity protection
Communication	RS485	Isolation 3kV
Warm-up	<140 s	Cold start
Operating temperature	-21～56 ℃	Industrial grade
Explosion protection	Ex ia IIC T4	Optional

Typical Deployments

Three ways this sensor shows up in an IoT project, for laying out a design and for judging the payback:

Manufacturing and Energy Sites

On a line or in a power room, the sensor can hand readings to an MES or an EMS, so key process values or energy data are collected at the edge and sent up.

Municipal and Utility Sites

For scattered points and outdoor cabinets, the hardware covers wide temperature and lightning protection, which suits a long run and a low-latency watch on water, gas, and street lighting.

Campuses and Buildings

Bring the sensor into campus energy management or building automation for sub-metering, abnormal alarms, and linked actions, and cut manual reads and patrols.

Installation, Grounding, and Maintenance

Before power-up, confirm the supply range and polarity. If the feed is uncertain, check bus voltage and breaker rating with a multimeter.
Use shielded twisted pair for the communications run, bond the shield at one end, and keep it out of long bundles with high-power cable.
For first go-live, prove two-way read and write and the threshold triggers against the platform in the lab, then move the sensor to site.
Outdoors, drainage and airflow come first. Inspect the sealing faces on a schedule, and hold lightning-protection earth resistance to the local code.
In continuous service, spot-check samples and archive logs every 12 months.

Ordering, Documentation, and Support

SimtoLink supplies the hardware specification, an outline drawing, a wiring table, and a sample project. Volume orders can include a sample review and inspection at the factory. Warranty and calibration follow the contract and the documents shipped with the sensor.

Where Carbon Monoxide Is Watched

Carbon monoxide is a colorless, odorless asphyxiant. The watch is on poorly ventilated spaces and on incomplete combustion. The jobs below turn on mounting height, a link to the extract fans, and the maintenance interval, so the alarm stays inside the relevant GB limit and the IoT platform can take the event.

Underground Garages and Mechanical Ventilation

Place sensors on the drive lanes, in the dead corners, and on the fire-compartment boundaries. When CO crosses the threshold, the fans change speed, the zone valves move, and the entrance sign updates. Sharing poles and power with parking guidance and lighting-efficiency systems avoids paying twice for the ELV.

Boiler Rooms and Distributed Energy Stations

Watch the burners, the flues, and the duty area with redundant sensors. Readings go to the energy platform, the fire graphic display, and the work-order system. Inspect and replace the electrochemical cell on the annual cycle the code requires, and keep the calibration and replacement record for the fire-maintenance file.

Power Compartments in Utility Tunnels

Combine the CO reading with temperature, oxygen, and combustible-gas zone alarms. An edge gateway runs the local interlock and a delayed confirm, so the tunnel needs less long hardwire. Event video and the trend support the review after an incident.

Energy-Storage Compartments and Battery-Swap Stations

One input to early thermal-runaway detection, together with smoke, hydrogen, and VOC probes. Explosion-proof glands, armored cable, and equipotential bonding follow the hazardous-area classification, which is what a battery-swap safety review asks for.