Manual OC32/NG
VPEB
Control your Miniature World
Page 34 of 48
Version 1.0 – December 15
th
, 2017
2017 Leon van Perlo
Each pair can provide 4,8A as an absolute maximum
Take Care: this is a peak current. Continuous load shall be kept below 1,5A per channel
and below 2,5A total current for each driver module.
There is no current limitation in the OC32-ADM, so you have to take care of that
Fig 22: An installed ADM
6.1.9
Identifying the different ADM’s
If you have an ADM and it does not have a type description on it, you can identify which
version you have by the following:
•
OC32-ADM/SI: At the top-side the TBD62083 is present, the TBD62783 is missing and
at bottom-side the 4 IC’s next to “P” are present.
•
OC32-ADM/SO At the top-side the TBD62783 is present, the TBD62083 is missing and
at bottom-side the 4 IC’s next to “N” are present.
•
OC32-ADM/MX At the top-side both TBD62783 and TBD62083 are present, at bottom-
side 4 IC’s are present, 2 in the “P” row, 2 in the “N” row.
•
OC32-ADM/FH All components are present.
Fig 23: ADM’s, top-row=bottom-side, bottom-row=top-side
from left to right: SI, SO, MX, FH
Control your Miniature World
VPEB
Manual OC32/NG
2017 Leon van Perlo
Version 1.0 – December 15
th
, 2017
Page 15 of 48
risk to re-use equipment designed for other purposes, especially if your electronic skills are
limited.
2 Amps is a good start since the current cannot do too much harm if you make a mistake. It
may not be enough to power all the devices in your miniature world, especially if your
ambitions are virtually unlimited. In that case you can always buy a more powerful power
supply later on and use the 2Amp supply to service your OC32’s. More on multiple power
supplies later on, but the message for now is: Unless you already know exactly what you
need/want, a simple and standard 2Amp DC power supply is probably the best option to
start.
4.3
GND or reference voltage
We assume that you have a connection point in your miniature world that we can call 0V,
Ground (GND) or reference voltage. It might be that this “reference voltage” cannot always
be found easily, but in a layout controlled by a PC, this reference voltage often is the “GND”
of the communications port that your PC uses to control the layout.
The 0V/GND (as stated above) of your miniature world has to be connected to the GND
connection of the OC32. All points in figure 6 that are labeled “GND” are interconnected on
the module itself.
If your skill level on electronics is insufficient to find the reference point, then choose for a
separate power supply to power the OC32(‘s). In that case the OC32’s form a separate
subsystem within your miniature world and you won’t have to worry about the issue above.
4.4
Connecting power to the OC32
The power supply for your OC32 has to be a DC power supply with a Voltage level between
7V and 20V (preferably 15V max). The power needs to be smoothed but not necessarily
stabilized.
4.4.1
The standard method: through K1
Connect the minus-pole of your power supply to the connection of K1 marked GND/GD.
Connect the plus-pole of your power supply to the connection of K1 labeled PWR (figure 6)
If you leave the “Power” jumpers Jp1 and Jp2 on the module (as delivered ex-factory) the
supply voltage as provided on K1-PWR will become available on the 20-pin connectors K5A
and K5B on connections Vp1 and Vp2 (plus) and GND (minus), so you can feed your
connected devices with this. For detailed pin-out, see figure 24.
4.4.2
Use of separate power supplies for OC32 and connected devices
If the item to control requires a high supply voltage or may cause a lot of interference (e.g.
turnout coils with endstop), it can be wise to separate the power supply of the OC32 from
the one for the devices to control. You will then power the devices with e.g. a voltage of 18V
and the OC32 itself with e.g. 9V. This has 2 advantages:
•
Possible interference signals and noise from connected devices will not interact that
easily with the electronics. So therefore
in some cases
it can improve stability.
•
The voltage conversion on the OC32 will waste less energy and therefore there will be
less dissipation. While reducing the voltage from 9V to 5V less energy will be dissipated
than when the OC32 needs to reduce 18V to 5V
On the OC32/NG you’ll find two “Power jumpers” JP1 and JP2. These jumpers forward the
PWR power you supply to K1 to the Pin connectors. JP1 connects PWR to Vp1 on K5A, JP2
connects PWR to Vp2 on K5B. If you remove JP1 or JP2 the respective Vp will be separated
