So right now I am about neck deep in roughing in the wiring for the new layout. I am going to use an NCE DCC system and an industrial PLC for signaling, turnout control, and some other functions. I started off planning to use the NCE BD-20 block detectors to send information to my PLC, but after getting 8 of these units I can't find the other 12 I need. I called NCE for some technical information and also asked about when they may be making more available and didn't get any solid answer. The tech guy I talked to actually suggested using a current detector for another company as he said they are all basically the same.
So now I am looking at the Digitrax BD4N block detector. I like the fact it claims to cover 4 blocks in one unit (cheaper) and seems to be available. The spec sheet also says it is usable with other systems and has external outputs for signal systems. Great! Fantastic! From what I have been able to find online it looks like connection to the track power and subsequent tracks are pretty easy, but how about outputs from the detector? And can those outputs be used to drive relays so I can get the signals into my PLC? Better yet can the BD4N outputs handle a 24 volt DC signal so I won't need relays to handle the signal to the PLC? Or am I kind of stuck waiting until NCE gets the BD-20 back into production? I really want to get as much wiring done while there is more access. Once track and scenery start going in the wiring gets more difficult.
Good Luck, Morpar
A partial answer: The BD4N OCC outputs can be used to drive external logic devices. The outputs are opto isolated and designed only to drive other logic devices.They can only supply a milliamp or so. Driving a relay requires an extra transistor but works quite well. The common terminal, pin 10, can be connected to any positive voltage up to at least 12V. I don't know about 24V. The exact ratings of the opto isolators is unknown. Try asking Digitrax directly but good luck on that.
Charlie - Northern Colorado
So I need some help.... What is meant by "drive a logic circuit". I am trying to get feedback into an NCE AIU.
If I put 12v on Pin1/+common what "appears" on pins 7 - 10 (DS1 - 4 out pins). Is it something an Arduino can recognize on one of it's digital pin inputs?
Thanks.
Sorry but I'm not familiar with the Arduinos. I suspect you should connect the BD4N pin 1 to the 5V supply of the Arduino, not 12V. You may need a pull up or pull down resistor on the Arduido inputs. Elsewhere I've seen 22K recommended.
Puma61So I need some help.... What is meant by "drive a logic circuit". I am trying to get feedback into an NCE AIU.
not familiar with either bdn4 or nce aiu, but it sounds like the bdn4 occupancy detector uses opto-isolated transistor outputs and the aiu is a conventional input with a pull-up resistor.
the bdn4 4 outputs should be tied between an aiu input pin (1-14) and gnd to pull the input low. the opto-output has a polarity, the + side to the input pin and - side to gnd.
when reading the aiu, the input will be active low to indicate occupancy
Puma61Is it something an Arduino can recognize on one of it's digital pin inputs?
would be similar for an arduino with a pin configured as INPUT_PULLUP.
greg - Philadelphia & Reading / Reading