DZ trackside sensor and “We Honest” signal

@Roger Harms posted:

Hi everyone,  I am hoping to use a DZ-1070 trackside sensor to operate a two aspect signal from E-bay vendor, “WE Honest”.  Pre-testing has given me a puzzle.  Testing with a Lionel 1033 transformer, using the accessory posts.  The signal lights when wires attached to the accessory posts.   The sensor sends 10 volts to first the white wire and then the gray wire as expected using the sensor.  When I attach the signal wires to the output wires of the sensor they do not light, however.  I confirmed that both the white and gray output wires from the sensor show 10 volts AC, alternately.  What am I missing?

Wehonest lights are usually DC power, not AC.  I have similar signals that I know are DC powered, is the one you purchased listed as AC powered? 

@Roger Harms posted:

I confirmed that both the white and gray output wires from the sensor show 10 volts AC, alternately.  What am I missing?

According to the Wehonest website, the signals are expecting 3vDC, not 10 v AC.

Thanks for the good suggestions.  In this case, the spec sheet comes with a diagram indicating 9-16 volts.  It doesn’t designate AC, but the signal lights perfectly when directly connected to the accessory posts on the transformer.  (An old Lionel 1033)

Any other ideas?

@Roger Harms posted:

Hi everyone,  I am hoping to use a DZ-1070 trackside sensor to operate a two aspect signal from E-bay vendor, “WE Honest”.  Pre-testing has given me a puzzle.  Testing with a Lionel 1033 transformer, using the accessory posts.  The signal lights when wires attached to the accessory posts.   The sensor sends 10 volts to first the white wire and then the gray wire as expected using the sensor.  When I attach the signal wires to the output wires of the sensor they do not light, however.  I confirmed that both the white and gray output wires from the sensor show 10 volts AC, alternately.  What am I missing?

Looking at this picture and since the sensor has White and Gray wires, it seems like you are using a Z-Stuff DZ 1075.  Here's a link to the online instructions > DZ-1075

Do you have the Transformer, DZ-1075, and Signal connected something like this?

On the Lionel 1033,  for ~ 10VAC operation, connections to terminals B and C may be substituted for Hot and Common in the chart above.

Thanks again, for engaging your time and expertise.  The 1075 has  seven wire connections and I only have five, so I think it is the 1070.  My connection is as you show it, except I don’t have a blue wire to connect.  As currently connected the sensor output is as I would expect.  10 volts from white wire unless sensor activated and then 10 volts at gray wire.  I know diodes need the current to flow a specific direction.  Could there be some phase issue?

Ok, now I see the DZ-1070 Sensor for O or S Gauge on the Z-Stuff Product page here> https://www.zstuffexpress.com/...tputs-o-or-s-gauge-1

However, I don't see it listed on the Instructions Page, only the HO and N version.  That version of the 1070 doesn't have the Gray wire and has a different housing from yours. It would be helpful if you could post a picture of the instructions that came with yours.

Since the signal works when connected directly to the transformer, I doubt there's a phase or polarity issue.  Since there's here's no harm in swapping the transformer connections between the B and C posts with no other layout connections, you could try that to be sure.

The pictures don't show all connections at once.  If you were to post details of all connections between the Transformer, DZ-1070, and signal, this may reveal the issue.

The black transformer eats light, but here is a shot of my connections.  The second wire to C is from the signal.  I tried reversing A and C with no change.

Thanks this is helpful.  Where is the signal's Black wire connected? It also needs to be connected to the Transformer's C Post with the above arrangement.

Yes, it is the second wire connected to C.  I used an extension as repeated testing broke off the resistor in the other signal.  (I have four, all with same issue.).

The only thing left I can think of is that the Signal circuit may be drawing more then the 25mA of current that the DZ-1070 is rated to pass.  If you want to test this, try measuring the current the Signal is drawing when directly connected to the transformer (bypassing the sensor).

If you're unsure how to do this, please post a new picture showing an unobstructed view of the entire front panel of your meter and I can walk you through the process.

BTW, for testing circuits, I find alligator test leads to be very helpful in making temporary connections.  A close second are Wago 221 series lever nuts.

Alligator test leads sound like a great idea!  Thanks.

Here is my meter.  I hope it is adequate for this assignment.  

Unfortunately, this meter is not designed to measure Amps directly. However, if you still want to figure this out, there is a way to calculate the current using Ohm's law.   First, you'll need to measure and record the exact AC voltage ( V ~ setting on the meter ) across the resistor (one meter probe on each resistor lead) with the Signal connected directly to the transformer as before.

Next, set the meter to the 2000 Ω position and touch the meter probes together. If the value is not very close to Zero, note this calibration reading.

Then disconnect the Signal's wires from the transformer and measure the exact resistance of the resistor, with the meter's probes connected to the resistor leads as in the previous step.  Subtract the calibration resistance from this reading.  The difference is the actual resistance of the resistor.

Ohm's law is V = I x R; where V = Voltage, R = the resistance in Ohms, and I = the current in Amps.

Solving for current, divide the measured voltage by the actual resistance.  You should get a decimal value, which when multiplied by 1000 gives you the mA (milliamps) that one signal LED circuit is drawing.

If this is close to or greater than 25mA, then the DZ-1070 may not be up to the task of driving these WeHonest signals. It's possible that lowering the transformer voltage to 9 volts would lower the current enough for this to work, or maybe not.

My suggestion would be to contact Dennis Zander at Z-Stuff and get his opinion.  Unless I'm overlooking something, you may also need to consider using a DZ-1075 or some other Sensor.

Thanks again. I believe you have hit the nail on the head.  Calculation was way over 25 mA.  So before I let you go, would I be correct in my application of Ohm’s law that I could drop the amperage into target by adding a resistor to the circuit to bring it down below 25 mA?

I greatly appreciate your time and expertise.  I have learned a lot even if I can’t get these things to work!

Rog

Adding resistance (edit - meant to say ) *in series* with the LED will decrease the current flowing through the circuit.  It will also decrease the LED's brightness and at a certain point prevent it from illuminating at all.

This is unrelated to your problem, but when you solve it, you should change to a 9-16VDC power source for the signals.  The instructions show the power source with a +/- indicating it is DC.  While AC will work, it can significantly shorten the life of the LEDs.

Bob

I was not aware of AC impact on LED’s.  I have several DZ signals with sensors in the base distributed around the layout on an accessory bus coming from the AC transformer.   Sounds like I better change those out.

Thanks again to all contributors!

Roger, Depending on the other DZ sensors and or signals in use (some of which are designed to work correctly on AC or DC), it may be better/and/or less work to wire a rectifier diode (such as a 1N4001) in series with each LED unprotected from reverse voltage, such as the WeHonest signal or other plain off the shelf LEDs.  This extra series diode does several things.  It converts the AC from your transformer into half-wave pulsating DC before the LED, protects the LED from reverse current flow (LED longevity) and significantly drops the voltage across the LED.  Depending on the source voltage applied, it may also allow using a lower value resistor in series with the LED.

Here's a link to a good beginner's overview on using rectifier diodes> Diode Guide for Beginners

However, all this may still not be sufficient to get the DZ-1070 sensor to operate these WeHonest signals.  Out of curiosity, what was the calculated current flow you found yesterday?

Thanks again.  Will learn about rectifiers, thanks to you!  

The resistor did not register on 2000K, but read 0.96 on the 20K setting.  The cables themselves read zero resistance on all settings.  So V = 10 coming out of the DZ white wire, R = 0.96 ,  That is clearly a bit more than 25 milliamps.

So today I tried a 12 volt DC source.  (HO transformer). The DZ worked with that as well but only sent 5 volts to the white and green wire.  Unfortunately the WeHonest signal still wouldn’t light.  Directly testing from the HO transformer had them glowing nicely again, but I had to reverse polarity.  The DZ doesn’t work with reverse polarity, so I don’t think this is going to work.  Will need to try another sensor.