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IUH-F190-V1-*
Operation
7
Operation
7.1
General
The sections below contain information about the commands that relate to the read/write head
IUH-F190-V1-*. The commands are described using the example of an IDENTControl control
interface with serial interface. All other generally applicable commands and error or status
messages can be found in the manual for your IDENTControl control interface.
7.2
Basic Command Process
Interference Due to Multipath Propagation
The electromagnetic waves radiated by the read/write head do not just follow the direct route to
the tag, but are also reflected off objects in the vicinity, meaning that multiple partial waves
overlap with the waves radiated by the read/write head.
This overlap causes interference (i.e., exaggeration and dampening of the reception field
strength), leading to almost complete degradation. Depending on the environment, several
reflections may occur with differing intensity and distance. These different reflections lead to a
field strength in the measurement range that is difficult to predict. In the areas of degradation,
the prevailing field strength is weaker than the minimum detection field strength of the tag. As a
result, the tag cannot be activated for communication. Exaggeration of the field strength may
lead to unwanted excessive detection ranges.
1. Measurement Range
2. Degradation
3. Excessive detection ranges
The reflections and the resulting inhomogeneity of the field strength depend on the frequency
used. The absolute value of the field strength depends on the transmission power. Since the
tags move in the measurement range of the read/write head, and the environment can change,
it is advisable to repeat the commands at different transmission frequencies and at varying
power. Different transmission frequencies are advisable, since the manufacturing tolerances
and the immediate environment of the tag have an effect the tag's resonance frequency.
Several Tags in the Measurement Range
Each read or write command can access one, several, or all tags in a measurement range. The
process is controlled by filter masks, which are managed via the commands Set Filter Mask
(FI) and Activate/Deactivate Filter (MF). These commands allow you to detect specific tags in
the measurement range. see chapter 7.5.
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