SIC24 - Signal &
Indicator Controller
Tips for Successful Operation
1. The SIC24 requires a regulated 12 volts DC power
supply. Most analog 'Power Packs' will NOT work because
they do not provide smooth (filtered) DC power.
Also SIC24s may not work correctly with switching power
supplies.
2. The power supply must be isolated from the system
ground. That is, it can not have one of it's outputs
connected to ground (booster ground, loconet ground,
house wiring ground, etc). Some wall transformers have a
ground connection. Three prongs into the wall suggests
the negative output of the power supply is grounded.
3. When multiple SIC24s are used they can be all
connected to one power supply. The power supply must be
able to supply the current for all the SIC24s. The
plus and minus of the power supply must be connected to
the same power input terminal on each SIC24.
4. If you have not cut the termination resistor at
described in in the Serial Bus section of the manual, the
SIC24 will operate with out being connected to the bus
(Loconet). Operating a SIC24 in this way may be helpful
in isolating problems.
5. Be sure the LED current limiting resistors are not
less the 470 ohms. This is a general guide line for a
typical LED. LEDs operate with varying currents and
voltages. If you have a special LED you will need to know
it's characteristics in order to use it with a SIC24. You
should limit the current of any single SIC24 output to 20
ma and the total of any connector group of eight outputs
to 50 ma.
Note: Attempting to turn on all eight LEDs at 10 ma at
the same time from a connector group will exceed the
rating. However, typically in signaling and most SIC24
applications all eight outputs would not be turned on at
the same time. If you require more than five LEDs to be
on per connector group than you will have to reduce the
LED current.
6. When multiple SIC24s are used be sure to power up all
the SIC24 boards at once. A SIC24 requires bus (Loconet)
messages to know what it should do. If a required message
is not received for some reason, the SIC24 will not work
as expected. For example if the state message of another
device is sent before the SIC24 is powered up it will
miss the message and not respond correctly even though
the message was sent.
7. When multiple SIC24s are used there is a lot of bus
(loconet) traffic at power on. If possible power up
the SIC24s first and then wait 10 seconds or more to turn
on other devices and track power. The SIC24 delays at
least 4 seconds after power on to start sending messages.
Some SIC24s delay longer because the delay time is a
function of the base address. Also, the time to stabilize
the signals can be long because of all the messages that
are present at power on.
8. If you have been programming logic cells using OPS
mode, you can program CV3 with a value of 1 to reset the
logic state RAM. In many cases this will eliminate the
need to cycle power. If programming other CVs, power will
have to be cycled for those values to take affect.
9. You can alternately flash all the outputs by
programming CV3 with a value of 3. This can be used to
test output LED connections.
10. In some cases, attempting to reset all the CVs to the
factory default value or clear all CVs above nine using
the programming track does not work. This is due to the
fact that some systems do not keep voltage on the
programming track long enough for the SIC24 to complete
the programming of all the 200+ CVs.
11. CV1 is the same as the loco two digit address. Some
throttles like the Digitrax DT300 will not allow that CV
to be programmed higher than 127. In some cases it is
desirerable to program CV1 to greater than 127. There are
several ways around this for the Digitrax user.
1. If you have access to a DT100 throttle, you can
use it.
2. If you have access to a Zerphyr, you can use it.
3. Use addresses starting above 255 by using CV9.
4. Use DecoderPro