Hello, I am working with a 5V train pulse encoder (Scancon), and I would like to use this same signal in some different devices, four tracking cards, two PLC's... Does anybody know if there is an industrial commercial repeater to do it? The encoder has six signals A,
-A, B, -B, Io, -Io. I want to repeat these six signals in order to use them in different devices.
Hi, Haritztolete. You'd have to be a little more specific:
Encoders with 5V outputs usually have one of 3 types of outputs -- totem-pole (similar to a standard TTL output), open-collector (similar to an open collector 7406-type output) or line driver. Since you didn't specify the encoder, you should at least be able to tell that.
No matter which type of output you have, you might first check if there are going to be ground loop problems. If you're going to four tracking cards and/or two PLCs, it's possible they may be at different ground potentials. If they're at the same potential, and they're all the same type of input, why not just drive all four of them with the one encoder output? And if they're at different potentials, you might want to use optoisolation to avoid ground loops which might interfere with your signal at best, and may destroy your equipment at worst.
To be honest with you, despite the almost monomaniacal insistence of many people on only installing purchase parts, there comes a time when the blivet box is a really good idea, and this looks like it might be one of those. Assuming standard totem pole output/input, I'd just use four 74C914s at the input (with small series resistor at the input, and a 1K pullup if you've got an open collector output from the encoder), and follow them with four 74(HC/LS)04s to double-invert and send the signal out to your four destinations (or 7406s if you have current sinking or opto inputs at the card). You can always use a fancy connector and screen something on the blivet box to make it look store-bought for the customer if required.
| | VCC | + | | | .-. | 1K | |(If O.C. Output) | | | | '-' | IN | ___ |\\ |\\ OUT | o-------o-|___|--| >O--| >O-------o | 100 |/ |/ | 1/6 1/6 | 74C914 74LS04 | (or 7406 if req'd) | (created by AACircuit v1.28.6 beta 04/19/05
After all, the customer has to buy it from somebody. Call yourself a manufacturing company, sir. Your custom blivet box is now a store-bought item. Voilla!
If your job absolutely requires something manufactured by someone else, you might want to follow up with telling what type of output your encoder has, what type of input your cards have, and whether there's going to be a ground problem. Either that or better, try posting that information at sci.engr.control -- they're the PLC experts.
Good luck Chris
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