My Encoder Fails in over 2000 RPM

[Ronishune]

Hi, I'm using an Encoder with Pulses/Revol.:1024 - Power Supply: 12~30Vdc - Bidirectional + Zero - Line Driver - Radial Cable connector with Maximum load 25Kg. It must be able to operate in 6000 RPM speed and -30~85 degree centigrade. But it gives out false output over 2000 RPM in the environmental temperature. Can this problem be caused by RS232 and the length of the connection? If "YES" please advise me how to check and make sure about this?

 

[karesz]

Hi,
some thing isnt clear! How long is your RS cable?
Can you give us the datasheet/type Nr. pls?
Are you sure pls, that its RS232 system?
6000 rpm & /1kpulses=>6Mpps! Nice for some RS232 & more meter cable...
Maybe you must try it with RS422/485!
K.

 

[Ronishune]

Thanks, the cable length is less than 50m but surely more than 15m. So you believe that RS232 is not capable of handling this range of pulse!?
6000rpm=~100rps => 100kpps or 0.1Mpps.
for 2000rpm it makes 0.033Mpps which I don't know is a great range or not.
Using RS422 is a good idea (I'll go for that) but as the encoder was replaced in a factory, I'm not quite sure that I can use RS422/485. Can you suggest other solutions please?

 

[123jack]

I'm no expert here but a few things suggest themselves if the need is urgent.

1. Telephone the "factory" the encoder was made in and ask what they recommend.

2. Cut the RS232 cable and splice in a re-transmitter or protocol converter

3. Fully define the "pulse train" so you can work out the real data rate etc.

You might also want to stick a scope on it to look at the state of the signal.

Also check the RS232 shield isn't grounded at both ends (easy mistake to make) and define the handshaking and latency involved if timing really is that critical.

 

[IanP]

1024 pulses @ 6000rpm sounds like to high resolution ..
I don’t think you need it ..
Maybe you can replace it with one that produces 360 (or even less) pulses per revolution ..

IanP
:|

 

[karesz]

...000rpm=~100rps => 100kpps or 0.1Mpps.
for 2000rpm it makes 0.033Mpps which I don't know is a great range or not.
...

Hi,
your full right with data rate_my mistake,sorry!
I found some description, what can be interesting for you("With this 'wiring standard' employed distances of over 100 meters at 19200 baud have successfully been implemented, kind of a far cry from 75ft!" The realisation uses: ... every signal uses a twisted pair with one leg being a ground return...):
"Using RS232 over long distances"; http://www.marcspages.co.uk/tech/long232.htm
It seems me with 30-50meter & 30KBps as effective to long distance to be for that standard, but it depends from especially used ICs(RX/TX or line drivers receivers) & cables as others said, GND! of cable shildings too...
K.