User's Manual

Connecting via RS-232, RS-485, and Modems
4-4 apC/8X Technical Manual
RS-485 Connection
Use the RS-485 serial protocol to connect apC/8X panels in a chain. It is
possible to connect 16 panels on one chain. However, panel activity may
affect performance, so Software House recommends limiting the maximum
number of panels in a busy chain to 12.
Connecting apC/8X panels in an RS-485 chain
If the apC/8X is not the last panel in the chain (no termination):
1. Set S6-1 through S6-8 to Off, On, Off, On, Off, Off, Off, Off
2. Set S11-1 through S11-8 to Off, On, Off, On, Off, On, Off, On
Continue at step 3.
If the apC/8X is the last panel in the chain (with termination):
1. Set S6-1 through S6-8 to Off, On, Off, On, On, On, Off, Off
2. Set S11-1 through S11-8 to Off, On, Off, On, Off, On, Off, On
3. Use twisted, shielded 24 AWG (0.288 mm) cable, Belden type 9842 or
equivalent between the apC/8Xs and the host computer.
4. Tie the shield wires together where the two cables meet, but do not
connect the shield at the apC/8X.
5. Ground the shield wires at the converter board. A converter board is a
small circuit board with attached connectors into which you plug the
connectors from the host and the apC/8X chain.
If the converter does not have an available point to connect the shield
to chassis ground, connect the shield at the chassis ground connection
on only one apC/8X. A daisy chain line can have a total length of 4,000
ft. (1,219 m).
RS-232 to RS-485 Converter
You must use an RS-232 to RS-485 converter to convert the communication
chain to RS-232 at the host. Software House recommends a Black Box model
IC108A or equivalent. Additional information on the converter can be found
on the manufacturer’s web site, http://www.blackbox.com/.