As part of its ISO 17025 accreditation process, the South African Geosciences Council in Pretoria, are required to measure and record a large number of various laboratory environmental parameters in a multi-storey building. As with any data logging project, various monitoring methods are available depending on factors such as the number of measurement points, their location, how often sampling needs to be performed and of course cost.
challenge
Providing appropriate monitoring to the Commission addresses many of the Earth science challenges. Firstly, the head of the instrument needed to do the various types of measurements, including simple room temperature, differential pressure, water conductivity, and even surface temperature, costs as much as a mid-range family car.
Another problem is the layout of the eight floors. The service area was measured at different locations on different levels from basement to roof, all data was sent to a central location on the second floor and easily integrated into the LIMS system.
In addition, the selected system needs to be able to provide alarm notifications to building staff, within certain constraints. While some parameters, such as room temperature, were simply recorded several times throughout the day, others, such as the instrument's head temperature, had critical levels for which alarm notifications needed to be triggered.
Finally, due to the age and design of the building, there is a requirement to monitor flooding. In the past, when the roof's water system failed, expensive and delicate equipment suffered sustained damage. Therefore, some form of flood detection and event monitoring is a key requirement.
options
Requiring data from multiple applications that needed to be sent to a central point for easy integration into Parliament's LIMS system, traditional data loggers were impractical. Each data logger will require periodic manual downloads of data by one or a few workers, which will be labor intensive. An additional problem with this approach is that the data will not be available in real time.
Another option would be a centrally located data acquisition system with hardwired probes that propagate through the building. However, due to the large number of measurement points, and the complex layout of the building, this solution was rejected due to hardware and installation labor costs. It would also be impractical if data collection points needed to be moved at a later stage.
Therefore, the use of this type of data recording system narrows down to wireless data recording systems. Wireless technology holds the promise of making installation simpler than hardwired systems, eliminating the need for individual data loggers to be offloaded across a facility, and allowing simple relocation of sensors.
Solution ZW-001, ZW-003, ZW-005, ZW-006, ZW-007, ZW-008, ZW-RCVR, ZW-ROUTER
ONSET's HOBO® ZW series data nodes ZW-001, ZW-003, ZW-005, ZW-006, ZW-007, ZW-008, ZW-ROUTER are chosen due to some unique features, including software power, and Relatively low cost per measurement point.
These wireless data logging nodes are battery-powered devices that transmit logged data to a central receiver at user-specified intervals. They overcome a major problem in traditional wireless logging systems, which is that each node does not need to communicate directly with the receiver. Each node can be configured in dual-purpose mode by connecting to AC power, as a data logging node, and as a router to pass data from other nodes. Through the combination of routers and data logging nodes, the system forms a self-healing network to ensure that the temperature and humidity logger data reaches the receiver ZW-RCVR through an alternate path, which should not be blocked.
In case of failure of the receiver or dedicated computer, each data node can store a large amount of data in the on-board buffer memory and send it to the receiver ZW-RCVR, again available.
Although the receiver ZW-RCVR and router ZW-ROUTER are normally mains powered, they also have an internal battery backup so that data can continue to be collected even in the event of a power failure. Hence, the potential of collected data being lost is minimized due to redundancy and backups built into the system.
Measurement
As mentioned earlier, the Geosciences Council has a collection of building parameter measurements. Many of these, such as the room temperature and relative humidity ZW-001, ZW-003, ZW-005, ZW-007 integrated probes, specifically measure the nodes used for these measurements. Use a normal thermocouple, connected to the analog input node to measure the higher temperature. Differential pressure sensors measure the entire air conditioner filter and are similarly connected to analog nodes ZW-006, ZW-008, ZW-005, ZW-007. Other parameters, such as water flow, use a third-party flow sensor connected to the node with pulse input ZW-008, ZW-005.
The temperature of the cooling water, as well as the temperature of the expensive instrument head, is measured with a thermistor probe connected directly to the analog input. In addition to environmental monitoring, one of the main requirements of the system is to detect potential flood damage in aging water storage systems on the roofs of buildings. This flood has caused costly damage on several occasions in the past, especially when it occurred on weekends when the building was usually empty. To reduce damage, a gutter system was installed to collect and reroute floodwater. The data nodes act as float switches installed in the sink for the flood detection system. -
Data and Network Management
Helps manage wireless data network nodes and data flows, accompanied by the use of Hobonode® Manager network management software. The software, which is part of ONSET's standard hoboware®Pro software BHW-PRO-CD package, displays a list of all data nodes and measurement points of the network, along with current status and measurement values. Along with this view are other frames that display graphics of selected measurement points, and a frame that is used to configure and display alarms.
The software can be configured to allow automatic sending of periodic remote location via FTP and email data, or to a local network folder.
In real-time graphs, graphs can be grouped by measurement type or displayed individually. The time in the graph can easily be swapped between the last 4 hours, 1 day, 1 week and 1 month using the preset button, while another button allows the graph to be printed to the default printer. This feature is used for geoscience manual monitoring of process time and value, as well as trends and long-term measurement stability.
hobonode also has a "network map" BHW-PRO-CD function that allows builders to import a schematic diagram of the eight floors of a building. The position of each node is superimposed on it. The last measured value from each node can also be displayed. For troubleshooting purposes, lines showing the connections between each node can also be enabled
alarm
Alarm notifications are usually sent by email, although visual and audio indicators on a computer monitor may also be used. Any triggered alarm can be programmed to send a message to any email address and an "alarm cleared" message can also be sent.
A number of system alarms are available to building personnel including "Node Missing" and "Node Battery Low", each measurement can also be set to an alarm level to send a message if it trips and/or the alarm clears.
Building staff primarily receive alert notifications via email for non-critical measurements. However, emergency alarms, such as temperature on X-ray machines and flood detection switches triggered by text messages to mobile phones, reduce equipment damage and economic losses.
in conclusion
Since the network of wireless data nodes ZW-001, ZW-003, ZW-005, ZW-006, ZW-007, ZW-008, ZW-RCVR, ZW-ROUTER has been installed, the Commission Geosciences has been able to meet its survey recording requirements ISO 17025, and being alerted to equipment failure or flooding.
A total of 28 wireless data nodes have been deployed, which measure eight different parameters at a total of 56 measurement points in 20 rooms. Node locations are distributed over seven floors of the building, and all data is returned in real time back to a central collection point.
Data can also be exported into the local LIMS system via the integral web server, to any user on the network, and periodically.
