Single to Quad converter

[Maint_1]

I’ve got a single to quad encoder converter on one of my retrofit kits serial A50398. Since day one the operators have been reporting that the spindle would just shut down for no reason. I’ve checked the error log in my spindle amp and found that I have a high number of latching faults due to feedback error. I checked my voltages at the board DC 4.98 pins 2-9. I checked my single ended signal from the encoder going into the converter 4.8 volts. Coming out I’m at 2.9-3 volts. I’m thinking this is my problem. Can I get the converter replaced?

[CNC-Global]

I used this Simple IC to convert Single Ended to Quad with amplification
IC number : AML26LS31

aml26ls31.pdf

(559.21 KiB) Downloaded 325 times

Ajax has a TTL2DIFF board you can use it also

[CNCguy]

I believe that the differential levels normally range between approximately .5 V to around 2.5V (or more),
not necessarily 0V to 5V like is commonly assumed. Are you using a scope or just a meter ?

[Maint_1]

Using a scope. I would expect the quad output to be 5 volts.

[Maint_1]

See comments here.

http://www.ajaxcnc.com/ajaxbb/viewtopic.php?f=20&t=380

[CNCguy]

Differential quadrature outputs are not 5V signals.

http://www.ajaxcnc.com/ajaxbb/download/file.php?id=297

[Maint_1]

So I hooked up a scope to see what I would get directly out of a Dynapar encoder that Ajax and Centroid sell with their kits. What I found is the incremental pulses where roughly 1 volt less then VCC or 5 volts. If I set my power supply to 5 volts exactly my signals were 4 volts, 4.9 then 3.9 and so on. So with my 4.98 at the TTL to DIFF converter I would expect 3.98 not the 2.98 I'm seeing. I'll test the new converter when it gets here to see exactly what the input versus output is.

[Maint_1]

New TTL to DIFF converter installed last week and I'm now getting a half volt higher out put, about 3.5. I'm hoping this solves my problem.