Block detection - Digitrax or RR-CirKits?

[Bill H]

Group:
I am starting to wire for block detection and was wonder about your experiences and preferences. I am using Digitrax DCC on my layout with JMRI Dispatcher Pro. I have operated on some layouts using Digitrax BLD 168s or smaller variants and have heard how great they are - and then heard horror stories on other layouts. Seems the BLDs they work well - when they work. RR-CirKits, well I have used the locobuffers for years and always had good support.

Thoughts? Recommendations? I would really like to hear from those with actual experiences.

Kind regards,
Bill

[John]

I have BDL-168s, BD-4s,  and the original RR-Circuits BD1's   



They are both current drop detectors .. and work very well on my layout .. which is pretty large ..  I haven't noted too many performance hits .. the biggest draw back is you have to run extra wire for the block bus

Gary Hinshaw has the RR-Circuits coil based detectors .. I'll let him respond how well they work.

[superchief]

I run 4 BDL 162 with a total of 59 detected blocks for about 13 years now and have had no problems on my Santa Fe-All the Way layout. I also have a JMRI dispatchers panel on 3 screens still a work in progress. Gordon

[jagged ben]

We have RR-Cirkits coil (CT) based detectors at the club.  They work great, even on DC. (I assume that they work on DC because our DC supplies are PWM types.  But I digress.)  I believe they are quite a bit more economical than the Digitrax, and I doubt there are any practical drawbacks compared to the Digitrax BLD bit ai have no direct experiencewith the latter. If you're going to use JMRI to handle your signaling I think there's no reason to be beholden to Digitrax.

[bdennis]

Have always used the BDL168 with no issues on my layout or about 5 others that I operate on that use the BDL168. Block for block the BDL is fairly economical.
I have RR-Cirkits TC64 for driving signals etc and function perfectly on the Loconet. So would recommend anything from RR-Cirkits.

I had issues with the earlier BDL162 with newer decoders with false detection about 10 yrd ago with what was then fairly old BDL162's. This was a known issue with the BDL162 and they are long gone, unless you pick some up on ebay.

[GaryHinshaw]

I have a Digitrax command station but I use RR-CirKits for all my stationary functions (Motorman for turnout control, Watchman for block detection, Signalman for signal driving) all hanging off a Simple Serial Bus that ties into Loconet, and all interfaced to JMRI and CATS.  Very happy with the whole package.  My only comment about RR-CirKits is that the programming documentation can be pretty opaque.  But once you have it figured out for one DCC address, the rest is simple.

I imagine the BDLs are fine too - it probably boils down to cost & convenience.  A watchman plus 8 CT coils will handle 8 blocks and cost about $60 USD, ~$7.50 per block.  Not sure what the Digitrax costs.

[John]

  A watchman plus 8 CT coils will handle 8 blocks and cost about $60 USD, ~$7.50 per block.  Not sure what the Digitrax costs.

A BDL-168 is $120 at modeltrainstuff.com ...   It has 16 detection sections ..  also ~ $7.50 per block ..   so cost is a wash ..

[GaryHinshaw]

A BDL-168 is $120 at modeltrainstuff.com ...   It has 16 detection sections ..  also ~ $7.50 per block ..   so cost is a wash ..

This raises an additional point to consider: the Watchman boards are only available in an 8-block configuration.  It's worth thinking about where your detection coils need to be and how the leads back to the board will work.  On my layout, and 8-block unit was fine, but a 16 block unit would have been pretty inconvenient.  On the other hand, if the BDL boards come in smaller units, then you'd have more flexibility, but maybe at a higher cost?

[John]

I think the rr-circuits block detectors have more flexibility .. a 16 block BDL board means you have to run more bus wires to a central point, where you have the ability to just branch off the main bus, and then  put the coil where it makes better sense ..

[Bill H]

I think the rr-circuits block detectors have more flexibility .. a 16 block BDL board means you have to run more bus wires to a central point, where you have the ability to just branch off the main bus, and then  put the coil where it makes better sense ..

John:
I was having a similar concern, my layout is over three rooms and the mainline runs 240'. The BDL 16 might be more economical but I would have to run a ton of wires a very long distance and aside from that inconvenience, I assume there must be some sort of limit to how far I would have to run each of the feeds from each block. With the RR-Cirkits I can put the sensors right near each block feeder, or alternatively use a lot of BDL 4s scattered around the layout rooms.

Thoughts?

Kind regards,
Bill

[eric220]

I think the rr-circuits block detectors have more flexibility .. a 16 block BDL board means you have to run more bus wires to a central point, where you have the ability to just branch off the main bus, and then  put the coil where it makes better sense ..

This. With the BDL, you will be routing track power from all 16 blocks all the way back to the detector. With the RR CirKits stuff, all you have to do is wire the feeders within a block together, and then connect the group to the bus. You’re trading running signal wires for running track power wires, but you’re also isolating your detectors from the power routing. If your Watchman goes down, track power doesn’t care; if the BDL goes down, it could take your track power with it.

[Bill H]

Eric:
That sounds logical, is there a limit as to how far the wire can run from the coil/detector back to the Watchman?

Kind regards,
Bill

[jagged ben]

Eric:
That sounds logical, is there a limit as to how far the wire can run from the coil/detector back to the Watchman?

Kind regards,
Bill

Not as far as I know.  We've run some as much as 20ft on the club layout.  (We're using older tower controller boards, actually, but I would imagine the electrical specs between the coil and board have not changed.)   Distance might affect the sensitivity adjustment of the detector, but then, I guess that's part of why you have that adjustment.

[GaryHinshaw]

I have a block on my layout with a 20 ft run from coil to Watchman, using CAT5 wire.  It works fine with the nominal sensitivity settings, including detecting a single car with a single 10K resistor @ ~1 mA.

[John]

My layout is two levels, and I kind of pieced things together over the years.  I have two BDL168s, 5 DS64s, 4 SE8Cs and a few others. I also have a mix of detectors.  I built 30+ of the original BODs from RR Circuits which are connected to the DS's and SE8s via CAT5 wire pairs stripped from the cable.  There are also some of the newer old version BODs that Dick made on his circuit board machines, but not sure if he is still selling them.

The BDLs are located on the lower level, centrally located in two clusters where there are large numbers of blocks in a smaller area.  I've also used some of the remote RD2 diodes that digitrax sells that allow me to have a longer run to the detection section, but not require me to have a buss wire to the block from the BDL, just some CAT5.  http://www.digitrax.com/products/detection-signaling/rd2/

The BOD detectors from RR-Circuits are supplemented by some BD4s .. 

All of this feeds my JMRI setup through a locobuffer, which powers a CATS CTC panel running on a Raspberry Pi .  CATS was easier for me to set up for CTC than PanelPro


Bottom line, there are lots of ways of doing this .. if you are a tinkerer, then something like I have will keep you entertained .. if you want something straight forward then just pick on or the other .. Both manufacturers have integrated product lines that work well ..  I like Digitrax for its simplicty, but their detectors are current drop. Thats not an issue .. but some may prefer something else.  RR-Circuits is a good product, but they do seem to change technology periodically ..  The coil based detection may be more sensitive to hook up, but it;s much simpler ..

YMMV .. JFTRT
https://tonystrains.com/product/rr-cirkits-block-occupancy-detector-1-bod-1
http://www.rr-cirkits.com/picpcb.jpg