Sensor Network: What is the best radio connection for pharmaceutical rooms?
Setting up the ideal pharmaceutical temperature monitoring system has everything to do with the radio connection through the wireless sensor network. Currently, using wireless temperature sensors in GxP-compliant temperature monitoring solutions is the way to go, as the positive results speak for themselves.
Setting up the best radio connection is not particularly easy. There are various factors like the type of infrastructure, interference, the wireless performance for the radio connection, and frequencies that should be used that might work against successful implementation if not done correctly.
Below are highlights of those factors and how to work around them for the ideal radio connection for your pharmaceutical room.
Before finding out which is the finest radio connection, it is important to find out how the sensor network works. For a temperature monitoring solution that is GxP compliant, the temperature is first measured by a sensor.
This data is then transmitted through a device known as a bridge and lastly ends up in a software where the data is archived, and the reports can be generated. This procedure can be done in five different ways, with only one using a wire as a communication protocol.
First, both wireless and Bluetooth® data loggers use Bluetooth® as their communication protocol to generate PDF reports through the sensor network.
Secondly, both proprietary antenna and public antenna wireless monitoring solutions use non-wired communication bridges like signals to send information from the sensor.
Lastly, there is a wired monitoring system that uses a wire to communicate in the sensor network, as the name suggests. Using a proprietary antenna in the 868MHz in the US and 915MHz in the EU is the most commonly used frequency band and setting up a good radio connection starts with this.
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Private vs. Public Infrastructure
The next step in using radio technology for a pharmaceutical room is choosing the right protocol and infrastructure. This entails knowing if the communication protocol is of a defined standard and if one should use a public or private antenna network.
There are several advantages and disadvantages that come with using either a private or public antenna network for your sensor network.
The main disadvantage of using a private antenna network is having to own an antenna at every point one wishes to communicate to and from. When it comes to Bluetooth®, one has the choice of using an available antenna, but will further have to install an app to pair the antenna to the device.
The huge advantage of using a public antenna network, on the other hand, is the benefit of using infrastructure that is already there. The newly available Mobile-IoT protocols LTE-M and NB-IoT are very promising and expected to be widely available in most industrialized countries.
Signal strength and wavelength are the two most important factors when it comes to comparing the radio strength of different frequencies. The performance parameters of the two frequency bands are highlighted below.
For Bluetooth®, whose frequency is 2.4GHz, the range and wavelengths measure about 50 meters and 12cm, respectively. This frequency band is ideal for the transmission of large amounts of data like documents over a short distance, which could be the device and the antenna. This is the reason why several peripheral devices like speakers use this technology.
As for the 915MHz/868MHz band, the range and the wavelengths measure 1000m and about 35cm. This band is perfect for the transmission of tiny amounts of data over a long distance. It is mainly used in various industrial applications such as the security or fire system. Due to its long-distance characteristic, it is the perfect frequency band to use for your wireless temperature monitoring system.
Micro Positioning of the Sensor
As mentioned earlier, different frequencies have different wavelengths. This, therefore, means that as the wave peak and wave base are moving in a room, they are subject to some interference depending on the size of the wavelength.
Under the perfect conditions, which are no absorption, no reflection, and no wave interference, the wave base, and the wave peak should be able to move freely to all the points within the RBR range.
One can only move a sensor that is already in this range if there is a standing wave that has resulted from a zone of interference. Standing signal waves and interference are the two major causes of a weak signal. Moving the sensor out of this zone will significantly improve sensor connection.
Interference Factors and Their Mitigation Measures
There are several inhibitors to good sensor communication that can either temporarily or permanently influence the connection. Radio systems are always used in dynamic environments, which means that the people or objects within that environment are continually moving, and so are those interference factors.
Below are several interference factors and how to mitigate them.
Walls and Racks
Most walls are made with concrete and metal, which can partially absorb or reflect signals between the data loggers and the transmitters, which can significantly weaken the radio signal.
One way of dealing with this is ensuring that the transmitters and the data loggers have direct intervisibility.
Pallets and Products
Any mass between the transmitters and the data loggers significantly weakens the radio signals.
Mitigation measures include waiting till the facility is fully loaded then determining the final position of the transmitter to avoid any signal interference. If this doesn’t solve it, one can move the transmitters slightly.
Forklifts, Loaders, and Humans
These components are continually moving and blocking signals, which may cause short disruptions on the signal. Brief interruptions on radio connections are inevitable, and there is little one can do to mitigate this. It simply cannot be done without the workforce and machinery.
What one can do, however, is install an alarm delay so that temporary loss of connection is not interpreted as sensor failure by the system. Sensors usually have buffer storage that will send the data once the connection is back up again.
Other Radio Systems
Some devices present in the workplace may emit radio signals that are the same or close to that of the temperature radio system causing short interruptions. This problem can be dealt with in the same way as the forklifts, loaders, and human problems.
Having a good radio connection for a pharmaceutical room has numerous benefits for both the facility and the end-users. Following the practices mentioned above will ensure that a pharmaceutical room remains how it was designed to function.