Help using a operational amplifer as a 2 position latch circuit

djsfantasi

Joined Apr 11, 2010
5,839
Thank Djsfantasi...

I'm familiar with (real) RR traffic control systems...In my former life, I used to design them..:D
I just didn't understand the relationship of the TS's statements...

eT
LOL! Sorry for preaching to the choir.

I don’t understand many of the TS’s statements, as well.
 

Thread Starter

sornjs

Joined Dec 29, 2017
29
I don't recall why a SPDT switch wasn't originally used everywhere.
INFORMATION: The club used the Circuitron switch motors to power the turnout frog. It was discovered that if a wheels caused a short the PCB track used for this purpose became a fuse and disappeared. I recommend anyone using Circuitron in this manner interpose a relay between the Circuitron and the frog.
 

eetech00

Joined Jun 8, 2013
1,740
Thanks again gentlemen. It's been about a year and I am now beginning the process of obtaining components and building some of these units.
I recently found out that after I left the "old" model railroad club they decided to operate more like real railroads.
er..ok..

They decided to operate the "Main Line" using "Dispatch" to control all mainline turnouts (you might call these things "Switches" since they change the direction of a train or maintenance equipment that need to use the railroad to get to where they need to maintain the railroad. It so happens that if the Turnout Control Ground is controlled through a SPDT electrical switch, one of two sets of Push Buttons and Controlled Capacitors can be used (the set selected by the SPDT switch). I don't think I found out about this when I installed the original system.
Care free operation, railroad main line turnouts controlled locally as originally installed. Dispatch control does "not" work",
These main line turnouts may be where two mainlines converge or where turnouts allow movement to storage tracks of many types.
Its been awhile since I been around real train operations, but the Mainline referred to a higher speed, main "route" track. Every few miles there was a slower speed section of parallel track, called a "siding", that is connected to the mainline with "Turnouts" at each end (aka switches) where opposing trains could "meet and pass". This was the sidings' main purpose, although it could be carefully used for other purposes. I think this is what the TS is trying to describe. The switches used for these turnouts were usually electric switch machines that had relatively slow movement.

Dispatch operation, railroad main line turnouts "can not" be controlled locally, only by the dispatcher has control.
Not true. Real railroads usually had a way to locally control a control point in the event of an emergency (if dispatcher control was unavailable, for example). A local control system would allow a signal maintainer to control switches and signals as if controlled by the dispatcher, while being in radio communication with the dispatcher.

I noted a question concerning

This same system was not used on or "yards" where train cars and engines are stored since storage may be over turnouts and random or "normal" turnout positions may cause problems to turnouts, tracks or rolling equipment. These model railroad turnouts were controlled with toggle switches. Real railroad yard switches were controlled locally, manually.
Yes...the same switches were not used. In Yards (like Classification Yards) the switch machines were pneumatic and were extremely fast!
The switch points would throw in a second or two.:eek: In Classification yards, they used to roll train Cars down an inclined section of track to get them coasting and throw switches in front of them to separate the cars into trains based on the final destinations. There was also sections of track with pneumatic braking. However, the switch and signal control logic circuits prevented any invalid switch positions. This was true for yards or mainline territory.

Anyway...this might be why toggle switches were used for the model RR....to eliminate any delay.

eT
 

djsfantasi

Joined Apr 11, 2010
5,839
Anyway...this might be why toggle switches were used for the model RR....to eliminate any delay
Good theory, except that it was explicitly stated that he was using Circuitron Tortoise switch machines. The name includes “tortoise” for a reason. They cannot be operated quickly. Like a tortoise, they are slow motion and their mechanical drive prevents them from operating w/o delay. Note that SPDT or DPDT toggle switches are specified in their wiring diagram.
 

eetech00

Joined Jun 8, 2013
1,740
Good theory, except that it was explicitly stated that he was using Circuitron Tortoise switch machines. The name includes “tortoise” for a reason. They cannot be operated quickly. Like a tortoise, they are slow motion and their mechanical drive prevents them from operating w/o delay. Note that SPDT or DPDT toggle switches are specified in their wiring diagram.
Yes...except the TS is trying to make a distinction between yards and something else for some reason. I’m trying to understand the TS’s statements...maybe I should stop..LOL

eT
 

djsfantasi

Joined Apr 11, 2010
5,839
Yes...except the TS is trying to make a distinction between yards and something else for some reason. I’m trying to understand the TS’s statements...maybe I should stop..LOL
We are in page 5 of this thread. I’ve asked several times what the distinction is. I have yet to get an answer.

IMHO, he doesn’t know. He’s been given verbal descriptions and is trying to make. distinction, without understanding why. Electronics and model railroading are both hobbies in which I participate. The distinctions he is trying to work with are unrelated to the wiring requirements. At best, they affect the electrical switch physical location and do not affect the wiring.
 

Thread Starter

sornjs

Joined Dec 29, 2017
29
56 65
First, I would like to thank all for their assistance.

Second, I would appreciate answering any questions any may have.

Finally, I would like to know who prefers (circuit POST 56) OR (circuit POST 65). (SOME CONSEQUENCE HERE)
 

xox

Joined Sep 8, 2017
382
56 65
First, I would like to thank all for their assistance.

Second, I would appreciate answering any questions any may have.

Finally, I would like to know who prefers (circuit POST 56) OR (circuit POST 65). (SOME CONSEQUENCE HERE)
Neither. The circuit from post #14
is probably the most stable, low-wattage switch for the job. You'd need two LM324's for two sets of switches but still better in the end. Driven by momentary switches and gives you two out-of-phase outputs (just run a line from the output of the second inner opamp to a voltage follower just like the other inner opamp does). Nice impedance profile too.
 

djsfantasi

Joined Apr 11, 2010
5,839
This is the second or third time I’ve asked and have yet to receive an answer. The manufacturers instructions call for either an SPDT switch (with a bipolar power supply) or a DPDT switch (with a simple 12VDC supply). Here are the manufacturers instructions!

What is the reason for using anything else?
 

xox

Joined Sep 8, 2017
382
This is the second or third time I’ve asked and have yet to receive an answer. The manufacturers instructions call for either an SPDT switch (with a bipolar power supply) or a DPDT switch (with a simple 12VDC supply). Here are the manufacturers instructions!

What is the reason for using anything else?
Ha! I was thinking the TS was simply referring to the one button for off and the other for on sort of problem. Maybe not.
 
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