Honeywell Midas-M Multi Gas Transmitter

Alarm 1: Relay 1 is activated, 4-20mA varies with concentration, corresponding to a constant red light on the channel and a red backlight.

Fault: Yellow light on, 4-20mA output 1mA, fault relay activated.

Suppression: Output 2mA, green light flashes, alarm output is suppressed.

Setting mode: Enter by long pressing the up and down keys to configure key parameters:

Alarm settings: Each channel can define 2 levels of alarm thresholds, hysteresis, delay time, and lock/unlock modes.

4-20mA output: Map 0-100% range to 4-20mA, supporting special state outputs such as fault (1mA) and suppression (2mA).

Network configuration: Supports static IP or DHCP, default IP is 169.254.60.47, subnet mask is 255.255.255.0.

（2） Calibration and maintenance functions

Calibration process:

Zero point calibration: It needs to be performed in an environment without target gas, and confirmed after the reading stabilizes. It is suitable for sensors other than O ₂.

Range calibration: Introduce a known concentration standard gas and confirm after the reading stabilizes. The O ₂ sensor is calibrated with 20.9% air as the calibration point.

Flow calibration: Adjust the pump speed to stabilize the flow at 600cc/min, and recalibrate after replacing the pump or filter.

Bump Test: A functional test to verify the responsiveness of sensors. The steps are: enter test mode → enable collision testing → introduce test gas → confirm alarm triggering → reset ventilation. It is recommended to use target gas or cross sensitive gas (such as O3 can be replaced by NO ₂) every 6 months.

（3） Network and Remote Management

The device is equipped with a built-in web server that supports access through browsers such as IE and Chrome. Its features include:

Status monitoring: Real time display of concentration, flow rate, temperature and other data for each channel.

Configuration management: remotely modify alarm thresholds, network parameters, and other settings.

Log query: View event records such as alarms, faults, calibration, etc., and support graphical display.

Certificate Management: When enabling HTTPS secure access, device certificates need to be installed (detailed steps apply to Chrome and IE browsers).

Maintenance strategy and fault diagnosis

（1） Preventive Maintenance Plan

Component maintenance project frequency note

External filter replacement takes 3-6 months. Corrosive environments require a shortened cycle

Internal filter replacement 2-year model 780248

Pump module replacement 2-year model MM-PM

Leakage inspection, pressure testing for 6 months, sealing of inlet/outlet after component replacement, verification of flow failure alarm

Adjust the pump speed through flow calibration and replace the pump or filter to ensure a stable flow rate of 600cc/min

（2） Common fault handling

Flow failure (F41): manifested as a flow rate<70% of the nominal value for 24 seconds. Troubleshooting steps: check if the filter is clogged → confirm that the pipeline connection is tight and leak free → check the pump operating status → replace the pump module.

Sensor malfunction (F50): REFLEX ®  Test failed, possible reasons: sensor aging → exposure to interfering gases → physical damage, the solution is to replace the sensor box.

Communication failure: Web access failed, check network connection → verify IP configuration → restart device → update firmware.

Technical parameters

Dimensions: transmitter 136mm × 83mm × 152mm, relay module 137mm × 84mm × 41mm

Weight: transmitter 1.3kg, sensor box 0.17-0.22kg

Working environment: temperature 0-40 ℃, humidity 20-90% RH (non condensing), pressure 700-1300hPa

Certification: CE (EN 50270), ETL (UL 61010-1), PoE (IEEE 802.3af)

Application scenarios and selection suggestions

Midas-M is suitable for scenarios that require simultaneous monitoring of multiple gases, such as:

Semiconductor cleanroom: detecting special gases such as SiH ₄ and HCl

Chemical storage tank area: monitoring toxic gases such as NH3 and H2S

Laboratory ventilation system: monitoring O ₂ content and VOC leakage

Pharmaceutical production workshop: detecting process gases such as CO and Cl ₂