When installing interrogators, not only is the optimization of the interrogation field important but several other considerations must also be taken into account. They are
- Ensuring equipment safety
- Ensuring employee safety
- Maintaining proper functionality
- Making proper connections for power and data
- Understanding the environmental limitations of the equipment
One of the important decisions you have to make is where to locate your interrogator to minimize the risk of damage. In the case of a dock door interrogator, for instance, knowing that a material-handling device, such as a forklift, may miss the door from time to time helps you choose the optimal location to ensure the interrogator is out of harm's way.
Initial attempts by major RFID manufacturers to build prefabricated door portals showed that these manufacturers had given little thought to these real-world situations. Interrogators in these early solutions were mounted about six inches off the floor, and they were not only difficult to access for troubleshooting, but the devices and their connections were also easily damaged by moving vehicles such as forklifts.
Careful consideration should be given to employee safety when determining where to place interrogators. Units should not be placed in locations where they can be an obstruction or a trip hazard. If the interrogator is being mounted on a vehicle, neither the interrogator nor its antennas should affect visibility or operator maneuverability during the operation of the vehicle.
Ideal placement of an interrogation zone is vital for proper functionality. To determine this, the intended primary function must be defined; only then can it be determined where the interrogator and antennas must be placed as well as how the antenna must be oriented to achieve maximum accurate reads. Ensuring that the expected read is realized is critical to the success of the operation.
Clean power and data connections are also important. For a small price you can buy a basic power analyzer at any major retail department store. This tool determines that the power circuit is wired properly and grounded. Usually, this device has a series of three to four LEDs on it that, when plugged in, light up to indicate various conditions in the wiring. These conditions can include
- Ground fault
- Reverse neutral/hot
- Reverse neutral/ground
If more serious problems are suspected, a qualified electrician should be called in. He or she will bring a more advanced power analyzer that detects conditions such as
- RMS voltage quality (sags, swells, flicker)
- Impulsive voltage quality (transient voltage)
- Harmonic voltage quality (harmonic voltage, harmonic current, harmonic power, inter-harmonic voltage, inter-harmonic current, harmonic phase angle, total harmonic voltage distortion, total inter-harmonic current distortion)
Normally, this level of investigation is not required. Most sites already have certified wiring. However, in the odd situation in which the equipment repeatedly fails, it might be a power issue. When this happens, a certified professional should be consulted.
When installing RFID systems, best practice is to use an uninterruptible power supply. This will prevent system failures in case of power shut downs.
Using a network analyzer to ensure connectivity and throughput are consistent and reliable is also always a good idea. A network analyzer enables you to capture and examine data from your network. You can browse the captured data and view detailed information for each packet that has been captured. A network analyzer also provides detailed information about current traffic, as well as overall protocol statistics and more. Many network analyzers support various protocols including IP4, TCP, UDP, IEEE 802.2 frame, Ethernet II frame, NetBIOS, IPX, and others. In addition to real-time monitoring, most network monitors include an extensive array of filter options that allow you to limit capture based on IP address, port, protocol, MAC address, packet size, and other criteria.
If the interrogator is not communicating with the network systems, the data that is critical to the business will be lost; this is why using a network analyzer is important.
Consideration should be given to the environmental conditions of the physical site where you will be locating the interrogators. Several factors need to be evaluated when assessing the environmental conditions, such as
- Temperature minimum/maximum
- Chemical exposure
- Splash conditions
Not many of the "off the shelf" interrogators will survive all these extreme conditions. Making the choice of a proper interrogator for your specific environment is critical in reducing the costs involved with replacing frequently damaged equipment and the downtime associated with hardware failure. A thorough environmental study is always recommended even if the conditions seem to be readily apparent.