[jimairth]

those traces look great to me, they are from the output of the 7414 i assume? before or after the caps installed? (just so I can learn a little too)
I was reading the pokey manual a little- there is a lot of settings in there!! What do you have pin 13 set as in the encoder configuration?
and how is the cheetah board connected to the pokey board?

[jkcab95]

No! I could not get the 7414 to output anything but a steady 1.25v. I don't think I was using the proper resistor capacitor combination? The trace is with the two resistors for the cyn70 and a .1uf cap across the signal and 0v. The filter cap had little effect if any!

The pokeys manual is a bit confusing and almost seems contradictory. I say this because you need to look at the plug in manual as it has much fewer settings. You are not able to use a lot of the settings in pokeys outside of Mach3 plugin. There was a post in the Mach support forum about this problem. The poster used a different sensor but with the 7414 for filtering. He finally solved his problem with some setting adjustments but they were in the Mach4 plugin and Mach3's plugin dose not have those settings. Every time I try to post over there it gives me an error and then when you try to post later it says you have already posted yet it has been 48 hours and I do not see my post?

I sent a new ticket into Pokeys support and hope they will answer today! Sometimes you get several reply's in a day and other times you need to wait a few days? They are real slow with Mach3 problems as they are expending all their efforts on Mach4. I have several machines running Mach3 and am reluctant to trade one set of problems for a different set. I purchased the board from Arturo at CNC4PC and he tried to help with some of the issues but would prefer I switched to Mach4. I would then have to learn LUI language and rewrite all of my visual basic scripts.

I built a tool changer and wrote the script for it and it works well except it will not do a tool change in MDI? It works great inside a program though? Well I digress I need to solve this problem so I can move on to the next one. I am still trying to decipher Poblocks so I can figure out how to make the spindle closed loop with PID. They do not support it but say it can be easily done with Poblocks. I say everything is easy if you know how!!!!

Thanks,

Jeff

[jimairth]

1.25 V is not either of the 2 possible outputs for the 7414!! -is the pokey terminal 13 set for an output vice input?
Your square wave looks perfect-drop the caps and 2k output resistor on the 7414.
try disconnecting the pokey term 13 and hook the oscope up to the 7414 output solo-to make sure the 7414 isn't blown.
if it is at least you have 5 more to play with!!

[jkcab95]

Well I am fried! I just don't understand what I am doing wrong. Pokeys plugin only gives the option of Index pulse input! I stayed late after I received your post and bread boarded the 7414 again. I had read a post over at the Mach form (PoKeys57CNC, spindle speed measurement jumps like hell) and this guy had the same problem but was using Mach4. If you have the time please take a look. It is one paragraph and a schematic with photos of his scope trace. His trace was better then mine before he added the 7414 and he was having problems.

I tried his schematic on the bread board and it was a no go. The only difference is he is using a cyn37. I think I am using the wrong set of resistors and caps and am having a current problem. I am guessing here? My power supply for my bread board is a 5v 1 amp wall wart. I have a bench supply but I don't drag it out for a small circuit. Am I feeding the 7414 too much current and blowing it? I can not find a max current for the supply voltage. It just says 7v max. I tried all three that i had purchased with the same results. 4.5v with the new layout.

I came home tonight and looked through my component drawers thinking I would try a two transistor schmitt trigger. I found a dozen 7414 I did not know I had! I waited three days for the one's I ordered.

I told you I posted to Pokeys support. They replied with a copy of the guys schematic I am asking you to look at! I replied back that I already did that and then they told me to go out side the Mach plugin and try adjusting the filter slider for fast encoders? I did that and it had no effect so I replied with that.

I'm lost and am wondering why this seems so difficult?

Jeff

[jimairth]

Carsten's circuit looks fine-putting the load resistor on the other side of the phototransistor allows you to get closer to 0volts when off at the expense of a lesser on voltage. note that he is using 1k ohm load resistor to bump up the current, higher currents tend to swamp out any noise and improves the delta V between on and off of the phototransistor
the 0.1 uf cap on the 5V supply is common and a good practice. low pass filter looks good as well, but i would still like to see an oscope trace on the 7414 output when connected and unconnected.
the 7414 hardly draws any current- 10-20 ma, any 5 V source would do.
edit-i'm still confused on the 1.25V output of the 7414, could you be in oscillation? oscope would show that.

[jkcab95]

Jim,

I came in early to breadboard the circuit as Carsten drew it. I decided to power it with The pokeys board and then check it with the scope both connected and disconnected. I

I had powered down the system last night and shut down the computer. I finished the circuit and started the computer, powered the system and warmed up the scope. I went to connect to the pokeys board and When I started Mach3 no Pokeys found! Closed out of Mach and went to the Pokeys software and no Pokeys found. I have but a few hairs left on my head to pull out!!!

I had to restart everything and attach the Pokeys via USB as it no longer recognizes Ethernet?

Back to the test. No good! I get a flat line steady dc signal. I tested after the 1k ohm resistor with the rest of the circuit disconnected and I get no voltage swing. The problem is the CYN 70 must have a different rating then the CYN 37 he is using? As for the led resistor the higher the resistance the lower the current. The CYN 70 need somewhere in the neighborhood of 180 - 220 ohm to be bright enough to reflect back to the photo transistor. As to the photo transistor's load, 1K ohm is not enough to get a swing in voltage to feed the input of the 7414. The original load I started with was 33K ohm and it looked great until I connected it to the Pokeys board. After much back and forth with Pokeys support it was determined that the 33K ohm caused too high an impedance. Reffering back to the CYN 70 data sheet I decided to use the 10K ohm they show in there example. After doing so and then adjusting the distance of the sensor to the black and white surface I finally got what you saw on the scope.

Now when I hooked that signal into the 7414 I got 1.25 v. If I add the Carstens filter before the 7414 and the .1 uf cap I get 3.05v. If I change the load resistor from my 10k to 1k I get over 4v. No matter what I do I get a steady dc signal from the 7414??????????

So now I am back to square one with Pokeys with no Ethernet connection! and I am still in electronic hell with feed back and I am sure they are going to get frustrated with me again.

I do diagnostics all day at work to determine the cause of a problem. I always take the scientific approach and try to determine what variable changed. when I attempt to repair the problem or process I try to stick to one variable at a time. Not having the knowledge base in electronics I feel like I am stabbing in the dark.

I am so sorry for the long post and I hope you are not growing weary of trying to help me. I really do appreciate all your help thus far.

Jeff

[jimairth]

Well, this IS confusing for an armchair quarterback- if the 7414 output is disconnected from the pokey then the only 2 states it can output iare 0.3 V or 3.3 V, if its anything else
then its broken-maybe only 1 inverter maybe all of them(if the 5V supply was bad)
I like your approach-1 thing at a time-lets return to what works-10 k load resistor on photo transistor-verify it works
2. switch load resistor to emitter side-check on and off volts(this will bring the off volts down which I think was part of the prob initally)