The Dräger PointGard 3700 is a complete 1-channel gas detection system for detecting combustible gases or vapors in ambient air. In the robust yet compact IP66 housing already contains all the necessary alarm equipment.

The PointGard ­3700 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 controller and the necessary alarm equipment such as flashing lights and horn. The AC versions of the PointGard ­3700 can be operated with the optional mains plug at any standard power outlet. To be able to position the PointGard ­3700 and the sensor optimally, they have been separated from each other. This allows the PointGard ­3700 with its alarm devices and display to be mounted at eye level, while the Dräger ­PIR ­7000 sensor can be placed as close as possible to the measurement location. The maximum cable length between PointGard ­3700 and sensor is 30 m. The sensor Dräger ­PIR ­7000, may be installed in hazardous areas. Appropriate accessories are available for use in ducts and ventilation shafts.

Application

The PointGard ­3700 is used where a gas concentration needs to be monitored locally. A typical application is the measurement of flammable gases and vapors in unventilated or closed rooms. For this, the PointGard ­3700 is installed outside the room at the entrance and the PIR 7000 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 the integrated alarm devices. It can also trigger automatic ventilation so that the concentration is lowered and the room can be entered again without danger.

Sensor Technology

Inside the PointGard ­3700, the proven electronics of the Dräger ­Polytron ­8700 are used. Both hardware and software have been evaluated by TÜV (Nord) and have provided evidence of SIL2 capability. The sensor is the Dräger ­PIR ­7000, which has been tested for suitability for measurement and is SIL2-capable. 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. The use of gas-specific absorption curves allows the target substance to be switched without subsequent recalibration. Depending on local conditions, the calibration interval can be up to one year. With this sensor, the PointGard ­3700 is able to measure a wide range of explosive hydrocarbon gases and vapors in a range of 0 – 100 % LEL (lower explosion limit).The Dräger ­PIR ­7000 allow continuous measurement under atmospheric conditions in a temperature range from -40 °C to +65 °C.

Integrated Alarms

The PointGard ­3700 already includes visual and audible alarms. 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. The horn volume can be adjusted to suit either industrial or laboratory applications. The side mounted horn silence button can be set to reactivate the horn in 3 minutes, 6 minutes, or permanent off until the next gas alarm.

Power Supply

The PointGard ­3700 contains a 120 … 230 VAC/ 24 VDC power supply.It can optionally be ordered with the power cable and country-specific plug. If a local 24 VDC supply is already available, a variant without power supply unit is also available.

User Interface

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 ­3700 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.

Interfaces

In addition to the integrated alarm means, the PointGard ­3700 also has dry contact switching relays. These allow additional automated switching measures. Relays are available for A1, A2 and faults. In addition, an external digital input such as a fault contact of neighboring machines, can be read in and thus the green light (safe status) on the PointGard ­3700 can be switched off. For integration into higher-level systems (visualization 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 synchronize settings with a connected Dräger REGARD 3000 or Dräger ­REGARD ­7000. In addition, remote access is possible via HART® using Dräger PolySoft software or other HART® communications device.