Honeywell LC13-510 Manual page 68

B.2 RESTRICTIONS TO TOTAL REPLACEMENT
If you are contemplating the replacement of all K4LCN processors in Five/Ten-Slot
Modules, be aware that the Clock Source/Repeater board is the single point ground
connection for the LCN cable shield. Therefore, even if the 12.5 kHz (Subchannel) clock
function is not being used, a CS/R or other grounding means is still required on each coax
segment.
Dual Node Modules can be connected to provide that single point ground without requiring
a CS/R. See Dual Node Module Service in this binder. If there are no Dual Node Modules
on the coax segment to provide that ground, then total replacement can only be
accomplished by replacing two Five-Slot Modules with two Dual Node Modules.
B.3 PREREQUISITES
The system must be up and running on Software Release 500 or later before performing the
processor replacement. You must have an LCN I/O card of revision T or later (either in the
module or in spares). If the card in your module is an LCNFL, it (or one in spares) must
be a revision F (or later).
B.4 NODE APPLICABILITY
Check that the K4LCN replacement is applicable to the intended node:
1. Visually confirm that there is NOT a Clock Source/Repeater (CS/R) board in the rear of
the module. If there is a CS/R board and if it is necessary to replace the processor
board in this node, replace it with the same type processor board. Obtain the same type
processor board from the spare parts supply or from another node in the network. If
you remove a processor from another node, replace it with a K4LCN per this
procedure. Be sure, however, that the memory and other requirements of this
procedure are met.
2. For performance compatibility, processor board types in redundant node pairs should
not be mixed. If you must replace a processor board and the affected node is one of a
redundant pair, a K4LCN processor board must be installed in its partner also. See
subsection B.6 below.
B.5 MEMORY SIZE
Determine the amount of memory in the node, including all memory boards and any
memory on the processor board to be replaced. The replacement K4LCN must have at
least this much memory. Having more memory is not a problem. Because the K4LCN
board is available with different memory sizes, ensure you are installing the right size by
comparing the tab portion (last three digits) of the part number on your board with the
following table:
51401996-100 = 4 megawords
51401996-200 = 8 megawords
Dual Node Module Service
51401996-300 = 16 megawords
B-2
B.2
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