User guide

PlantLinc PLR5000 User’s Guide
P/N 161-09888-001 DATA-LINC Group
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beginning to use a back-off algorithm. When the Remote has failed to transmit the packet the number of times
specified in Max Remote Retry, it will attempt to transmit to the Master on a random basis.
The Retry Odds parameter determines the probability that the Remote will attempt to retransmit the packet to
the Master; a low setting will assign low odds to the Remote attempting to transmit and conversely a high
setting will assign high odds. An example of how this parameter might be used would be when considering
two different Remotes in a multipoint network, one close in with a strong RF link and the other far from the
Master with a weak link. It may be desirable to assign a higher Retry Odd to the Remote with the weaker link
to give it a better chance of competing with the closer remote for the Master’s attention.
Another parameter in a multipoint network is (4) DTR Connect. When set at (1), the Remote will connect to
the Master if it is free when the DTR line goes high on the 9-pin RS232 connector. In setting (2), the radio
modem will accumulate data in its buffer and transmit in a burst when the buffer is full. This mode is valuable
when a network has many low data rate devices and it is desirable to increase overall network capacity. In
setting (0), the radio modem will transmit when RS232 data is received.
The Repeater’s hopping pattern must also be set in a multipoint network; this is accomplished with parameter
(5) Repeater Frequency. Setting this parameter is in contrast with point-to-point mode where the Repeater
automatically uses the Master’s hopping pattern. The Repeater may be programmed to either use the Master’s
hopping pattern selection (0) or its own selection (1).
Option (6) NetWork ID allows multipoint networks to be established without the use of the Call Book. If the
NetWork ID is set to any value lower than the default (255), the Remotes in the multipoint network will
communicate with the first multipoint Master or Repeater heard with the same NetWork ID. When the
NetWork ID is used, multipoint Masters and Repeaters may be replaced without reprogramming all of the
Remotes in the network. In addition, this allows a Remote to establish communications with different Masters
(though not at the same time) without having the call book numbers in the Call Book. This is very useful in
mobile multipoint applications.
Option (8) Remote/Repeater mode allows a PLR5000 in a multipoint system to simultaneously act as a
Remote and a Repeater. When in this mode, a PLR5000 will repeat any packets sent from a Master as well as
send them out the RS232 port. This allows a PLR5000 set as a Repeater to act as a Remote at the same time. 0
disables this mode, 1 enables it. For this feature to work, the modem must be configured as a point-to-
multipoint Repeater.