RollPCI User Manual
Hardware Installation
Issue 3 Rev 1
Page 10
© 2015 SAM
2.4 RollNet Over RS485
RollNet coaxial segments may be joined by ‘RS485’ links to over come the 64 unit load limit.
The ‘RS485’ link is connected between two RollCall units that support ‘RS485’, and each of
these two units is connected to a different RollNet coaxial segment. The RollCall units at each
end of the ‘RS485’ link monitor the signals on the link and regenerate the signal on the
RollNet cable; and vice-versa. A unit (or an oscilloscope) connected to the RollNet will not be
able to distinguish signals from units on the RollNet segment from those transmitted via the
‘RS485’ link. The RollNet segments and the ‘RS485’ link appear to be a single cable run.
Unit Type
Unit Load
IQ 3U Box (IQ3A)
2
IQ 1U Box (IQH1S)
4
IQ 1U Box (IQH1A)
2
Roll PCI
1
