A simple, quick-to-install monitoring system developed by Xodus Group for long term unattended use in hazardous areas.

The Hazardous Area Long Term Monitoring System (HALTMS) from Xodus provides a simple and cost-effective solution to measuring vibration, dynamic pressure and stress on pipework and associated structures in hazardous areas.

Incorporating a modified version of our Long Term Monitoring System (LTMS), the HALTMS includes protective Zener barriers required for the operation of sensors in hazardous areas. Mounted in a certified EEx ‘d’ flameproof enclosure, the entire system can be installed and operated unattended in areas classified zone 1 or zone 2, eliminating the need for long cables running from the measurement sensors to a logger in a safe area. This radically reduces the time and costs of deployment and eliminates the need to either install or find additional space in cable transits.

System installation by expert Xodus engineers can take place within seven days, depending on the number of sensors required and site access. Standard configuration HALTMS systems are kept in store meaning most customised options can be assembled in under three weeks.

Sensor types
In its standard configuration, the HALTMS acquires signals from a maximum of 32 sensors at rates of up to 1,000 samples per second. It acquires data from ATEX EEx ia rated ICP accelerometers or dynamic pressure sensors and ‘simple apparatus’ sensor type strain gauges and potentiometric displacement gauges for the dynamic measurements required for vibration analysis. Standard process 4-20mA pressure, temperature and position sensors can easily be installed and recorded.

Weighing approximately 110kg, the system can be bulkhead mounted using mounting bars placed across the back. Alternatively, it can be supplied on a free-standing base that can be temporarily fixed to the installation floor or wall to prevent movement.

Electrical requirements
The electronic hardware is housed in an ATEX rated EEx ‘d’ flameproof enclosure with the circuits to all sensors routed through protective Zener barriers. Power for the system hardware is supplied from a convenient power source capable of being isolated without impacting the operation of other equipment. The HALTMS is configured to run off a 110 to 240 VAC 50-60 Hz supply and consume less than 100 W. Powering the system from other types of supply can be arranged on a case by case basis.

Prior to deployment Xodus can supply all component certificates of conformance, system wiring diagrams and sensor and enclosure hazardous area certificates required to support management of change procedures or other client processes required to allow the system to be installed. System certification is prepared in advance of shipment and installation.

Data storage
All data is recorded on removable 1 or 2 terabyte disk drives. The HALTMS can be programmed to record and store data continuously or for selected durations and time periods. In both cases the data is broken into data files of a user-selected duration. In the event of the removal of power from the system only the current data file is lost. On return of power the HALTMS is programmed to restart and resume recording data at the beginning of the next recording period.

Data formats
Data is sampled and stored in a multichannel Universal File Format (.UFF, .UNV) or .WAV files which can be directly imported into engineering analysis applications such as MATLAB, nCode GlyphWorks, ME’scope or PULSE. For each recording period statistical data results are computed and stored in Comma Separated Values (.CSV) files. The statistical values stored for each recording period for each data channel are the Minimum, Maximum, Mean, Standard Deviation and Root Mean Square. For strain or stress data the 2D Rainflow Cycle Count can also be stored.

In operation the client or supervising engineer can inspect the statistical data results using a spreadsheet application such as Microsoft Excel to rapidly identify the areas of interest, possibly correlating them with the associated process conditions at the time from the process Distributed Control System (DCS) records. Further detailed analysis of the recorded time history data can be carried out by the client or our Vibration Engineering engineers using the associated multichannel time history data.

Data harvesting
Normally the system will operate unattended and store data onto a removable USB storage device for subsequent analysis. The current system status, including the storage capacity remaining, is shown on an illuminated four line LCD display visible through the window on the enclosure.

Data is normally transferred from the system by connecting a laptop or similar portable PC device to the HALTMS system though an Ex ‘d’ rated Ethernet RJ45 connector on the HALTMS enclosure. Data is transferred to the laptop using file transfer commands familiar to Microsoft Windows users. Depending on specific requirements for the operation of portable electronic devices in a hazardous area, data transfer may have to be performed under a temporary hot work permit.

On-line interrogation
A Fibre Optic (FO) ethernet connection can be set-up from a safe area to the HALTMS in the hazardous area. The FO ethernet connection allows a laptop to be connected to the HALTMS and the system to be interrogated and / or configured from the safe area without the need to power down the device or have a hot work permit issued.