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I have to convert a 0-24V (HTL) signal to a RS-422 signal. (It's a signal to enable data acquisition on a device that requires RS-422).

We found a device from Motrona (PU210) that converts our HSL encoder signal to RS422 and it works fine. But I can't find anything for simple signals.

device

Is there a way to do such a conversion with simple industrial components (optocouplers, ...)?

Null
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Simon
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    never heard of "HSL"! is that some kind of analog signal? under which conditions do you want to turn on the RS-422-connected device? – Marcus Müller Oct 05 '21 at 16:04
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    Also note that questions asking for product recommendations are explicitly off-topic, so you should re-formulate it to ask for a solution to a problem, not a product. – Marcus Müller Oct 05 '21 at 16:04
  • Do you have 5V available for the converter circuit? What are the speed requirements? What are the skew requirements between the two complementary outputs? – Mattman944 Oct 05 '21 at 16:16
  • Removed the request for product recommendation (unfortunately, it would be very useful). I'm working in an industrial environment, we avoid designing using chips and basic electronic components. Regarding the speed, it's not to transfer data. As long as in less than 500µs the signal gets converted, that's fine. I do have an isolated DC-DC that converts our 24V to 5V. – Simon Oct 05 '21 at 18:11
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    You still haven't told us what "0-24V HSL" means. "Hue, Saturation, Lightness" is the most common meaning. What exactly are you doing? – Transistor Oct 05 '21 at 18:17
  • Sorry, I meant HTL... (like TTL, but not 5V) Unfortunately I cannot change the question title. – Simon Oct 05 '21 at 18:57
  • Usually the logic levels are dictated by the application, so having an RS422 receiver would imply the use of the sensor of the same level. Makes no sense to install a limited speed HTL sensor and then convert the signal into high speed RS422, rather change the sensor. – Marko Buršič Oct 05 '21 at 19:49
  • It's a photocell (0-24V signal) and a camera that requires a RS-422 signal. I can't change the hardware. – Simon Oct 05 '21 at 20:23
  • Please [edit] your question with the additional details you've provided in comments. – Null Oct 06 '21 at 12:09

2 Answers2

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schematic

simulate this circuit – Schematic created using CircuitLab

Use a fast optocoupler, additionaly add a parallel resistor if 24V is not push-pull (HTL is, so R1 can be ommited), calculate limiting resistor R2. Use a schmitt trigger and RS422 line driver IC.

Marko Buršič
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If the speed isn't important, you can probably do it with just optocouplers and a few resistors. R3 and R4 are optional, but provide some protection against shorts.

And this assumes that your driving signal can drive about 10 mA.

schematic

simulate this circuit – Schematic created using CircuitLab

Mattman944
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