2
\$\begingroup\$

In the process of developing an RDM Compatible DMX receiver board (using a ATMEGA328) and I have been fortunate enough to come across kimliv's most informative answer concerning such a board;

DMX on Arduino with RS485

However I was wondering why (if) it is necessary to use a TTL Compatible isolator? In this case the 6N317 or if perhaps a more traditional repeater isolator style circuit could be implemented using a more common and cheaper isolator for example the H11A1 (which I just so happen to have in stock).

This all said it seems several DMX circuits I have come across utilise the 6N317 but so far as I am aware the transceiver (MAX481) could be used to drive other isolators.

Is there something obvious I am missing here? or anything in particular that makes the 6N317 quite so desirable for its use here?

thank you.

\$\endgroup\$
1
\$\begingroup\$

Is there something obvious I am missing here? or anything in particular that makes the 6N317 quite so desirable for its use here?

According to the data sheet for the 6N137 it can handle data rates up to 10Mbps: -

enter image description here

I took a quick look at the H11A1 and it has rise times and fall times of about 3 us. That informs me that it may be good for data rates of about 100kbps.

That's a big reason in my book for using the 6N137

\$\endgroup\$
1
  • \$\begingroup\$ i had considered this though disregarded it assuming that DMX was at low speeds, turns out DMX requires speeds of 250kbit/sec. thank you for pointing this out. \$\endgroup\$ – Crow Aug 24 '15 at 10:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.