Heidenhain Encoder - strange waveform help request

I hooked up my spindle encoder which is a 420 series Heidenhain to my oscilloscope and even though the encoder is listed as a square wave TTL encoder , I saw a sine wave? Upon rotating the encoder shaft the scope showed what looked like a TTL square wave going on inside of a sine wave. I really dont know what to think of it but would like to know if thats normal. If its normal, is there anything special i need to do with my HAL file to deal with the strange waveform or do I just treat it like its a regular square wave signal. Im using a MESA 7I76 and 5125 for the interface.

Thanks

Try here.
www.heidenhain.us › wp-content › uploads › 349529-2H_Rotary_Encoders_en.pdf

Well oscilloscopes tend to work better when you remember to hook up the probe grounds.....hahahaha...problem solved

Good. All I could find was 5Volt supply TTL square wave in a 420 encoder.

i have a liniair scale LS904 ml 370 from heidenhain on me mile machine  
i'm not sure  if the scale is broken or  the input  of the controle unit fails  
how can i find out if the scale work wel  ?
what is de basic set up ?
just power  5vdc  on  pin 3and  4 ?
when i use a scope between ground and  an output  what signal do i have to find  or do i need a pull up or down  resistor  ?
i found  in an old document  somthing like  15microampere on the output  
do someone know how to test the scale  
 

These encoders typically need an interpolator interface card
(EXE series)

it would be  a sinus output  

is the a way to  controle if the scale  is still ok  ?

Yes, but you will need the interpolator box that converts
the 11 uA Sine/Cosine outputs of the scale to higher resolution
TTL quadrature signals.

These (EXE boxes) are commonly available on Ebay

EXE box 101 o r 102.

 

What controller you have on the machine ?
If it is old Heidenhain controller , then directly supporting the 11uA encoder so no EXE will be present .
If other brand controller obviously there will be EXE to convert into TTL quadrature .
To test whether 11uA scale head is alive , you may check for current flow by applying supply to pin (3)5V & (4)0V .
If no current flow observed then LED is dead and reader head wont work
For other pins 1&2 5&6 7&8 you can check with multi-meter on diode check mode.
or If supply connected to 3&4 , you can observe resistance will change on 1&2 5&6 7&8
This is the simplest method to know scale is working.

If you have access to old Heidenhain DRO you can quickly check the scale