GFK-1322A
Chapter 4 Configuring the LBIM
4-7
4
CPU type
This field allows the user to choose the type of CPU to be used in the system. The choice
of CPU may affect the maximum number of network variables that can be assigned to
each of the registers. While the number of variables that can be assigned will depend on
a number of issues, in some cases the size of the particular register is less than the
number of allowed variables. In this case, the program will default to a maximum size
that corresponds with the register size for the CPU model chosen. If there is doubt as to
which CPU model will be used, choose the smaller (lower model number) of the available
CPUs to assure compatibility. If the number of variables needed exceeds the capacity of a
particular CPU, a larger CPU should be chosen. Keep in mind that there are limits to the
number of I/O references that can be used by any one module on the backplane. The
limit for analog references is 64 inputs and 64 outputs (%AI and %AQ) for all CPUs.
The limit for each discrete register is 1024 for the 351 CPU and 512 for all other CPUs.
Some versions of LogicMaster will not allow assignment of more than 16 analog inputs
or outputs to a single module.
Transceiver
Using a pull-down menu, the program allows the user to choose a particular transceiver
type for the configuration. This is necessary to assure that the proper communications
parameters are specified in the external interface file created by the program. If the
wrong transceiver type is configured, the module will not communicate properly. The
LBIM comes factory equipped with one of three transceiver types as listed below. Be
sure to choose the transceiver type of the module to be used.
Module Number
Transceiver
Description
PE693BEM350
TP/FT-10
Free topology twisted pair @ 78K bps
PE693BEM351
TP/XF-78
Isolated twisted pair @ 78K bps
PE693BEM352
TP/XF-1250
Isolated twisted pair @ 1.25M bps
L
ON
M
ARK
Objects
For information on L
ON
M
ARK
Interoperability guidelines and L
ON
M
ARK
objects, please
see the L
ON
M
ARK
Application Layer Interoperability Guidelines (Version 1.3 or greater)
published by Echelon Corporation.
SCPT_max_send_t
This field allows the user to set a maximum send time configuration parameter. This
parameter determines the maximum elapsed time between network transactions. If a
network variable update has not been sent when this time has expired, an update will be
transmitted. Sending an update will reset the timer. This feature is usually used for two
purposes. The first is to establish a “heartbeat” so that remote network members will
know if the LBIM node is offline if an update has not been received within a specified
time period. The other is to update variables on the network so that new network
members will receive current data within a specified period after being put on the
network. Setting this value to 0 (default) disables this feature.
Summary of Contents for 90-30 PLC
Page 4: ......
