Manual OC32/NG
VPEB
Control your Miniature World
Page 24 of 48
Version 1.0 – December 15
th
, 2017
2017 Leon van Perlo
5.3.6
Connecting multiple OC32/NG’s to a PC – Option 2
If you cannot or don’t want to use RJ45 cables, you can use the green 3-pole wire-end
connector and your own cable/wires instead. Be aware of the following:
•
The “cable” has to run past all modules, you must not create branches;
•
All connectors have the same pin-layout, so pin 1 is connected to pin 1, pin 2 is
connected to pin 2 and wherever necessary, pin 3 connected to pin 3;
The 3-pin connectors make chaining relatively easy. Strip about 2 cm from the insulation of a
wire pair near the intermediate module that you want to connect. Do that for both cable
ends (so the one from the previous and the one to the next module). Twist the stripped ends
of the wires with the same color of the two cables firmly together. Cut the blank parts to
about 1 cm and plug this in pin 1 of the connector. Perform this procedure for the other
wires of the two cables and plug the result in pin 2 of the connector. We assume that all
OC32 are on the same GND and that therefore the connection of pin 3 is only required
between the U485 and one of the modules.
The U485 counts as a ‘just another module’. It doesn’t
matter where in the chain the U485 is placed. Most practical
is at the beginning or end but can also be placed somewhere
in between. In figure 14 we deliberately put the U485
somewhere in the middle to show this. Note that in that case
you may
NOT
activate the terminator on the U485 but
MUST
activate the ones on the OC32’s at both ends of the chain.
Fig 14: Connecting multiple OC32/NG’s without RJ45 cables
Address
U485
PC
RS485 terminator activated
Address
Address
RS485 terminator NOT activated
RS485 terminator activated
RS485 terminator NOT activated
Control your Miniature World
VPEB
Manual OC32/NG
2017 Leon van Perlo
Version 1.0 – December 15
th
, 2017
Page 25 of 48
5.3.7
Connecting multiple OC32/NG’s – Other options
Of course you can combine options 1 and 2 as described above. Since the two RJ45’s and
the 3-pole connector are electrically connected, effectively every OC32/NG can be used as a
‘media converter’ from RJ45 to individual wires. Especially is you use a combination of
OC32’s and OC32/NG’s this may be of value.
5.3.8
The OC32/NG in a Dinamo(/MCC) system
If you deploy the OC32/NG in a Dinamo or Dinamo/MCC system and you use RJ45 cabling,
the OC32/NG is nothing more or less than another Dinamo module in the RS485 bus. So
use one of the RJ45’s to connect to the previous module and the other RJ45 to connect to
the next. See the Dinamo P&P Manual for further details.
If the OC32/NG is the first or last module in a Dinamo RS485 network, be sure that you
activate both terminators (data and clock).
5.3.9
The installation of a “real” RS485 network
The above describes a simple way of connecting a couple of modules to RS485.
In some cases it might be handy to install a “real” RS485 network. The “bus”
implementation is with respect to topology not that handy in all cases and sometimes you
want to be able to connect and disconnect modules at multiple positions in a flexible way.
For the record: a “real” network is not “better” or “more reliable” than a bus, but it can be
more handy and flexible. There are many ways of creating such a network. To prevent this
manual from becoming too bulky and because the matter also counts in a Dinamo system,
we will describe it in a separate document.
5.4
RS232 communication
In theory RS232 is usable with distances of up to tot 15 meters, but in reality you often
reach reliable communication over distances of up to 50 meters. RS232 is the standard
protocol that is offered by the COM-port of a PC or a simulated COM-port by means of a
USB-converter..
Today, the use of RS232 for communication with the OC32 is not recommended. The use of
RS485 is preferred by far. However, should you need an additional channel from e.g. a PC to
give additional commands to control functions for a day/night simulation, RS232 may be a
valuable option.
Fig 15: RS232 communication
pin4
Address
GND (0V)
RS232 TxD
GND
PC
pin2
