GE 90*-30 PLC Series User Manual

Also see for 90-30 PLC: Installation and Hardware Manual

Contents

GFK-1322A Chapter 4 Configuring the LBIM 4-74CPU typeThis field allows the user to choose the type of CPU to be used in the system. The choiceof CPU may affect the maximum number of network variables that can be assigned toeach of the registers. While the number of variables that can be assigned will depend ona number of issues, in some cases the size of the particular register is less than thenumber of allowed variables. In this case, the program will default to a maximum sizethat corresponds with the register size for the CPU model chosen. If there is doubt as towhich CPU model will be used, choose the smaller (lower model number) of the availableCPUs to assure compatibility. If the number of variables needed exceeds the capacity of aparticular CPU, a larger CPU should be chosen. Keep in mind that there are limits to thenumber of I/O references that can be used by any one module on the backplane. Thelimit 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 inputsor outputs to a single module.TransceiverUsing a pull-down menu, the program allows the user to choose a particular transceivertype for the configuration. This is necessary to assure that the proper communicationsparameters are specified in the external interface file created by the program. If thewrong transceiver type is configured, the module will not communicate properly. TheLBIM comes factory equipped with one of three transceiver types as listed below. Besure to choose the transceiver type of the module to be used.Module Number Transceiver DescriptionPE693BEM350 TP/FT-10 Free topology twisted pair @ 78K bpsPE693BEM351 TP/XF-78 Isolated twisted pair @ 78K bpsPE693BEM352 TP/XF-1250 Isolated twisted pair @ 1.25M bpsLONMARK ObjectsFor information on LON MARK Interoperability guidelines and LON MARK objects, pleasesee the L ON MARK Application Layer Interoperability Guidelines (Version 1.3 or greater)published by Echelon Corporation.SCPT_max_send_tThis field allows the user to set a maximum send time configuration parameter. Thisparameter determines the maximum elapsed time between network transactions. If anetwork variable update has not been sent when this time has expired, an update will betransmitted. Sending an update will reset the timer. This feature is usually used for twopurposes. The first is to establish a “heartbeat” so that remote network members willknow if the LBIM node is offline if an update has not been received within a specifiedtime period. The other is to update variables on the network so that new networkmembers will receive current data within a specified period after being put on thenetwork. Setting this value to 0 (default) disables this feature.