Always know what is going on in your plant: Gas detection system Statox 505 - SIL 2 standard


Source: Compur Monitors GmbH & Co. KG

Compur Monitors introduces a new toxic gas transmitter.

Reliability, feedback included

The Statox 505 is a 4 – 20 mA transmitter for toxic gases and oxygen. It complements the Compur portfolio of fixed gas detectors. With this new development Compur responds to an increasing demand for SIL standard gas detectors, mainly from the chemical and petrochemical industry.

Typical for Compur Monitors, they did not base their statistics on sensors for easily detectable gases, when they determined failure rates and error scenarios. They selected sensors for gases which are difficult to detect, like hydrogen cyanide and phosgene. The argument of the engineers was, if the database is good for these gases, it will be on the very safe side for any other gas.

All good stuff

Based on field – proven sensor technology, Compur developed a system that includes everything a state of the art gas detection system needs. It features modern hard – and software, smart sensor technology, heart – beat sensor test, seamless system diagnosis. All that and much more comes with the new Statox 505.

Why SIL?

In process technology the stress resistance of plant components becomes more and more important. The standards DIN EN 61508 and the product standard for gas detectors, DIN EN 50402 finally provides statistics to the user, with which probability a component may fail upon demand. Statox 505 has been designed to comply with these standards and thus provides reliable data to calculate the safety standard of the plant. It complies with SIL 2 according to DIN EN 50402. If it is operated as a SIL 2 component, the Statox 505 must undergo a regular proof - test as specified in the standard: No statistics can replace a test under real world conditions.

What is the benefit of SIL?

SIL standard plant components do not just complete their task - in case of a gas detector this would be to monitor the atmosphere for toxic gases - but also test and monitor all parameters that are essential for proper function. Statox 505 for instance continuously checks numerous parameters, such as sensor „heartbeat“, signal output, zero, ambient temperature, sensor memory, amplifier, CPU and power supply. In case of a problem an alarm is generated. Therefore it is more than unlikely that a system failure can go unnoticed. On the outside of the sensor head a green LED signalizes proper function. Even if safety integrity does not really increase the service life of system or component, it makes potential failures predictable.

Who tells you which product complies with SIL standard?

The necessary database to comply with the standard can be compiled by the manufacturer or by a third party. To excel a manufacturer in public to be SIL compliant, he should be listed by an independent organization, such as EXIDA. This name stands for „excellence in dependable automation“. It is the name of an organization, dedicated to review and check the plausibility of safety – relevant product and plant statistics. Whoever provides a serious database will be listed to comply with SIL standard. This so called EXIDA – List is a very important purchasing tool for engineering companies and end users. Since beginning 2010 the Statox 505 is listed by EXIDA.

Safety Integrity is compulsory – easy operation is the nice to have

The sensors of the new generation are plug- and play technology. This makes installation, start up and maintenance a child's play. They have an on - board FRAM memory, saving all parameters necessary for the operation. As soon as a sensor is connected to a sensor head, it downloads the data, identifying serial number, gas, measuring range, best before date and recent calibration. This converts the neutral transmitter to a specific gas detector, with a defined measuring range. An additional benefit is, that a sensor head can be very easily converted to another gas or measuring range.

The FRAM saves not only the identity of a sensor, but also its calibration and exposure history. This way the sensor communicates to the sensor head when and with which result it has been calibrated, and if it has been exposed to high concentrations.

Minimum time and work in the field

The sensors can be calibrated in the comfort of the workshop. For the user this means he never ever will have to do calibration work in the harsh elements. No more lugging heavy test gas equipment and gas cylinders in the field. All the user has to do after calibration, is to plug the sensor back in. To do that, he does not even need a tool! While the sensor is getting calibrated in the shop, the sensor cartridge can stay in place and protect the interior of the sensor head from dust and rain. Or the sensor is just directly replaced by a freshly calibrated one, this saves going to the sensor head twice.

The display and keys are located well protected inside the sensor head. In case work has to be done on site, these components are always clean and functional. Even the proof – test required by the standard is software supported, to make the users life as easy as possible.

Trouble – free wall or pipe - mounting

The Statox 505 comes with a stainless steel mounting plate for either wall or pipe – mounting. No need to open sensor head for plant installation. This can be important when the installation is done by personnel not familiar with gas detection.

Sometimes years may pass between installation and start up of a gas detection system. Another fact can save money: the sensor head can be mounted without sensor in the first stage, and then be fired up quick and easily by just plugging the sensor in. This provides the maximum operational time of a sensor.

Technical data

  • Product name: Statox 505 Transmitter
  • Manufacturer: COMPUR Monitors GmbH & Co. KG, D-81539 Muenchen
  • Detectable Gases: AsH3, Cl2, ClO2, CO, COCl2, H2S, HCl, HCN, NH3, N2H4,
  • NO2, O2, O3, PH3, SO2
  • Measuring principle: electrochemical
  • Operating temperature:-30°C to +60°C - 22 °F to 140°F
  • Storage temperature:-30°C to +60°C - 22 °F to 140°F
  • Humidity:0 - 99% r.F. (non condensing)
  • Pressure: 900 - 1100 hPa
  • Power supply: 12 -28 VDC, max. 22mA
  • Connection: 2 or 3 - wire
  • Output: 4 - 20 mA, max. load 700 Ohm
  • Service mode: 2 oder 4 mA adjustable
  • System fail: 0 mA at 3-wire, 2 mA at 2-wire operation
  • Overrange: 22 mA
  • Display: 8-digit, 14 segments
  • Dimensions (HxWxD): 200 x 120 x 90 mm (without mounting plate)
  • Weight: . 0,75 kg 1,65 lb
  • Approval: Ex ib IIC T4
  • Application: II 2 G
  • Approval no.: BVS 09 ATEX E 104
  • Voltage Ui:max. 28 VDC
  • Current Ii: max. 93 mA
  • Internal capacity Ci: negligible
  • Internal inductivity Li: negligible
  • EMV: EN 50270
  • Functional : SIL 1 or 2, EN 50402
  • Material:housing ABS chromium plated / mounting plate stainless steel
  • Protection class EN 60529: IP 65

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