PlantLinc
PLR5000 User’s Guide
P/N 161-09888-001
DATA-LINC
Group
12
Main Menu Option (3): Edit Radio Transmission Characteristics
When option (3) is selected in the main menu, the screen in figure 4 appears, which allows the user to modify
the radio transmission characteristics of the radio modems. As stated in the warning, these parameters are for
the experienced user who has a good understanding of the principles of radio data transmission. They should
be changed only after consulting this user guide.
It is important to note that the radio parameters between any radio modems in communication will be
determined by the settings for the Master (except when in multipoint mode, see (4) RF Data Rate below).
While the settings may be modified for the Remote(s) and/or Repeaters, they will be overridden by the
Master’s parameters.
Figure 4: Radio Parameters Menu
Shown below are example settings. Please refer to supplied configuration sheets for your modem’s
configuration.
(0) FreqKey
Selection (0) in the Radio Parameters menu allows the user to modify the hopping patterns of the radio
modems to minimize the interference with other PLR5000 radio modems in operation in the area. For
instance, if there were 10 pairs of PLR5000s in operation within a factory or refinery, changing the Frequency
Key would ensure that they would not jump onto the same frequencies at the same time for the same length of
time.
There are 15 choices available for the Frequency Key (0-9 and A-E). It is recommended that a list be
maintained of the settings for each Master to ensure that each is set to a different hopping pattern.
(1) Max Packet Size and (2) Min Packet Size Selections
(1) and (2) allow the user to designate the size of the packets (in bytes) used by the radio modem in its
communication link. This may be of particular value when using the PLR5000 with different communications
software packages; you may find that throughput is optimized when packet sizes are restricted by the radio
modem.
Packet size is determined by a combination of the settings entered by the user and the RF Data Rate. In
addition, the Max Packet Size is a function of the setting selected for the Min Packet Size. Tables 2, 3 and 4
provide the packet sizes for each different combination of settings.
