[chbot] TTL to Line driver
markaren1 at xtra.co.nz
Sat Sep 12 22:20:18 BST 2020
Have you looked into why your existing encoder is intermittent ? I have
seen problems with damaged seals leading to moisture and dust ingress,
which have in turn clogged the optical wheel. Also failed buffer ICs can
cause issues. Careful optical cleaning, and driver replacement is quite
Assuming that this is not possible...
Your description of single ended to differential TTL conversion sounds
suspiciously like a conversion between TTL and RS422. There are lots of
ICs available to do this conversion including the 26C31, which is a quad
RS422 driver IC. https://www.ti.com/lit/ds/symlink/am26c31.pdf
For optical-encoder type applications a popular signalling format is a
pair of quadrature signals (A+B) along with an index pulse (X). A have
some industrial shaft encoders which require power, and generate 3 pairs
of RS422 compatible outputs carrying A, B and X.
So how many channels do you need ?
From you original posting, it is unclear if you are looking for a
driver IC, an assembled PCB, or a complete, enclosed product.
RS485 is a half-duplex implementation of RS422, so it is possible to
take an RS485 unit, and wire it permanently in transmit. Hence my
original suggestion that https://www.trademe.co.nz/2775249657 might be
of use, but you may need several of them.
Hope you are well,
PS The SN75183 you reference is a dual RS422-like driver, with a rather
odd-ball input arrangement.
My encoder has become intermittent on my CNC mill. I have found that my
Liner scale from Aliexpress has the correct resolution to work with the
The problem I have is the linear scale is TTL output and the connection
I require is differential equivalent to a SN75183.
Anyone know of an off the shelf TTL to differential unit. My searches
don't yield much other than discrete components. Maybe there is another
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