Rs-485 To Lcn Converter Boards (Klcna, Klcnb) - Honeywell LC13-510 Manual

3.3.8 RS-485 to LCN Converter Boards CLCNA (OR KLCNA), CLCNB (OR
KLCNB)
For information on troubleshooting LCN problems, see Section 4 in LCN Guidelines,
Implementation, Troubleshooting, and Service in the LCN Installation binder.
If replacement of a CLCNA or CLCNB board is indicated, the following points are
important to know. Read all of the following points before beginning the replacement
procedure.
• If the CLCNA or CLCNB being replaced is one which has a coaxial cable
grounding wire on it (refer to Figure 2-6), use the following procedure. Before
disconnecting the LCN coaxial cable from the CLCNA or CLCNB, connect one
end of a clip lead to a metal part of the BNC Tee-connector and connect the other
end of the clip lead to Logic Ground. This procedure maintains LCN cable
ground during the board replacement, allowing communications to continue over
the cable.
• Before removing the CLCNA or CLCNB, disconnect the LCN cable by
disconnecting the BNC tee from the coaxial connector on the CLCNA or
CLCNB. Do not remove the individual cables from the tee—they must remain
connected so that communications can continue among the other nodes.
• The CLCNA and CLCNB boards were designed to be plugged and unplugged
from the I/O card cage with power on. Therefore, it is not necessary to turn off
power to the node during CLCNA or CLCNB board replacement. DO NOT do
this with any other board type or substantial damage may occur.
• While the BNC tee is disconnected from the CLCNA or CLCNB, remember that
there are exposed metal parts on this Tee-connector (and the clip lead if present),
and these parts are at ground potential. Do not allow these metal parts to contact
other components, or errors or damage may result.
The CLCN-A and CLCN-B board assemblies have replaced the CLCNA and CLCNB
board in current production and are functional on the same boards.
Dual Node Module Service 3-12
3.3.8
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