Model-CMS300

Supported Applications

The Dwyer Model CMS300 Carbon Monoxide Transmitter and Switch is designed to monitor carbon monoxide (CO) concentration in underground parking garages, vehicle maintenance facilities, or mechanical rooms. The unit provides a field-selectable current or voltage output proportional to the CO level detected.

Operating Conditions & Performance

The CMS300 operates within an ambient temperature range of -4 to 122°F (-20 to 50°C) and supports humidity levels from 15-90% RH constant or 0-99% RH intermittent. For best sensor life, storage is recommended at 32°F to 68°F (0 to 20°C). The device features an electrochemical sensor with a typical lifespan of 5 years and offers a measurement range of 0-300 PPM.

Performance specifications include:

• Accuracy: ±5 PPM or 5% of reading for 0-300 PPM (whichever is greater)
• Resolution: 1 PPM
• Response Time: <45 s to 90% of final value
• Coverage Area: 7,500 ft² (700 m²) or 50 ft (15 m) radius
• Output Drift: <5% per year in air
• Temperature Effect: ±2% over range

The unit is housed in UV resistant glass filled polycarbonate with an IP64 enclosure rating.

Configuration Options

The CMS300 series supports configurable analog outputs and alarm set points via internal jumpers. Key capabilities include:

• Analog Output: Jumper selectable 4-20 mA (loop powered) or 2-10 V (maximum load 2 kΩ)
• Relay Switching: Single-pole double-throw (SPDT), factory set for direct acting
• Set Points: Jumper selectable ranges of 25, 60, or 150 PPM with a differential/hysteresis of 3% of scale
• Relay Electrical Rating: 30 VDC, 250 VAC; N/O=5 A, N/C=3 A resistive
• Power Supply: 12-40 VDC or 15-32 VAC @ 160 mA max.
• Electrical Connections: P1 (4-pin connector) for power and signal; P2 (3-pin connector) for relay

Field calibration is performed using on-board zero and span potentiometers. The series supports the following accessories: Model GCK-200CO-2000CO2 calibration gas, Model A-507 calibration adapter, replacement CO sensor (part number A-505), and a security enclosure (Model A-GSTA-SE).

Key Product Differences

The series includes the standard CMS300 model and the CMS300-FC variant. Both models share identical performance specifications, measurement ranges, and output configurations as defined in the primary data sheet.