Dräger PointGard 3720, Detection of Carbon Dioxide

The Dräger PointGard 3720 is a complete 1-channel gas detection system for measuring carbon dioxide in ambient air. In its robust yet compact housing with IP66 protection class, you have all the necessary alarm equipment needed.

The PointGard 3720 is the optimal solution for all those who need a gas detection system but who do not want to go through the hassle of assembling all the necessary components. It contains the measuring function of a transmitter, the assessment function of a controller and the necessary alarm equipment, such as flashing lights and horn. The AC versions of the PointGard 3720 can be operated with an optional mains plug at any standard power outlet. For optimal positioning, the PointGard 3720 and sensor can be mounted separate from each other. This allows the PointGard 3720 with its alarm devices and display to be mounted at eye level, while the sensor can be placed as close as possible to the measurement location. The maximum cable length between PointGard 3720 and sensor is 30 m. The Dräger PIR 7200 sensor comes with our PointGard 3720, which is ideal for use in hazardous areas. In addition, appropriate accessories are available for use in pipes and ventilation shafts.

Use the PointGard 3720 where gas concentrations need to be monitored locally. A typical application is the measurement of carbon dioxide (CO2) in unventilated or closed rooms. For this, the PointGard 3720 is installed outside the room at the entrance and the sensor in the room to be monitored. This way, you are informed about the gas concentration before entering the room. If the set alarm limits are exceeded, the PointGard warns you with its integrated alarm devices. It can also trigger automatic ventilation so that the concentration is lowered and the room can be entered again without danger.

Inside the PointGard 3720, 3720, you will find the proven electronics of our Dräger Polytron 8720. Moreover, our Dräger PIR 7200 sensor with SIL2 capability makes it a perfect fit. This infrared transmitter with double-compensated 4-beam optics is characterised by excellent measurement quality and extreme long-term stability. It detects contamination of the optical system and warns in good time before the measurement fails so that the operator can remove the contamination. Depending on local conditions, the calibration interval can be up to one year. With this sensor, the PointGard 3720 is able to measure carbon dioxide in ranges from 0-2000 ppm to 0-30 vol%. The Dräger PIR 7200 allows continuous measurement under atmospheric conditions in a temperature range from -40 °C to +77 °C.

The PointGard 3720 includes visual and audible alarm devices. The bright and long-lasting flashing lights warn of danger from a distance in orange (pre-alarm) and red (main alarm). If a distinction is to be made between safe and unsafe conditions, there are combinations in green (safe) and red (unsafe) or green (safe) and blue (unsafe). The integrated horn has a sound pressure of 85-100 dB. It has been selected for industrial use in noisy environments. You can reduce the volume for less noisy environments, for example in the laboratory.

The PointGard 3720 contains a 120 ... 230 VAC/ 24 VDC power supply. You can also order it with a power cable and country-specific plug as an option. If a local 24 VDC supply is already available, a variant without power supply unit is also available.

The measured value, gas name and measuring unit are permanently shown on the display. If required, the concentration history of the last 15 minutes can also be shown. The display has a backlight in red or green to ensure readability even in poor lighting conditions. The colours are adjustable via a slide switch inside the device. Below the display are three status LEDs in green (ready), yellow (error) and red (alarm). All settings on the PointGard 3720 are made via a password-protected menu. The three-button control allows quick navigation through the menu items. Measuring range and alarm thresholds are already set to the usual values Ex Works. They can also be adjusted at any time.

In addition to the integrated alarm means, the PointGard 3720 also has potential-free changeover relays. These enable additional automated switching measures. Relays are available for A1, A2 and fault. Moreover, an external switching contact, for example a fault contact of neighbouring machines can be read in and thus the green light (safe status) on the PointGard 3720 can be switched off. For integration into higher-level systems (visualisation systems, data acquisition systems, PLCs, central gas warning systems), the analog 4-20 mA current interface according to NE 43 can be used. HART® communication allows you to synchronise settings with a connected Dräger REGARD 3000 or Dräger REGARD 7000. Furthermore, remote access is possible via HART® using Dräger PolySoft software or other HART® HHT.