s7-1214c Encoder and Signal Board

HI,

I have a encoder that provides 30 ppr at 5v. Knowing that the s7-1214c logic 1 has to be higher then 15vI bought a 5v signal board. This was the recommendation, to solve the problem. What I didn't know is that all the inputs on thesignal boards are sourcing type. Meanign it provides a 5v and is a logic 1 when grounded.

I waswondering if anybody has run into this problem, and if they have found a solution to it. Since I can not change the type of encoder that am using.

Thank you for your help...

Jay R001

HI,

I have a encoder that provides 30 ppr at 5v. Knowing that the s7-1214c logic 1 has to be higher then 15vI bought a 5v signal board. This was the recommendation, to solve the problem. What I didn't know is that all the inputs on thesignal boards are sourcing type. Meanign it provides a 5v and is a logic 1 when grounded.

I waswondering if anybody has run into this problem, and if they have found a solution to it. Since I can not change the type of encoder that am using.

Thank you for your help...

Perhaps they have made a conclusion that this is the most common use with such encoders.

Your encoder shall be NPN open collector and there shall be no problems, other encoder with 5V that I know is RS-422, but it has two wires for each tack.

Post the encoder type.

Sorry it took so long to reply got pulled off to do another job.

The encoder type is a minarik model pk24-5-30. I've talked to the powder feeder manufacture and they "Think" it is a open collector type of encoder.

My next step is just going to be to hook it up and see if it works. Hopefully i get some kind of reading since i had to redo the program from a s7-200 to the s7-1200. They have a little differences, but are almost the same. Will post results soon..

Oh thanks at least that answers the question of what type of encoder it is.

I hooked up the encoder just to see if i get anything. I would get a couple of counts but only when it is turned on or off. onces the motor is runningthe counter stops. And when the motor if off the output stays at a logic 1.

How wouldI connect apull up encoder to a sourcing output?

I've found this :

Encoder output:

Sink 0.8 Miliamperes @ 0.4V (NPN)

That is 10mA @ 5V. This translates into aNPN open collector with 500 ohm resistor in series with collector.

There is little data on SB 1221 and probably also wrong, it says Current consumption 24VDC is 15mA/input + 15mA, but there is no 24VDC, perhaps they meant 5VDC, instead.

15mA @ 5V could mean 330 ohm series resistor, or current limiter. I suppose this is cheap made and series resitor is used, so 500+330=830, when encoder output is low, there should be a current of 6mA sinking into encoder.

For the sb-1221 there are two types of boards. One is for 24v and the other is for 5v. I made sure to get the 5v for my project.

Good news is I got it working. i should of just hooked it up from the start, but i didn't want to take the chance of burning out the encoder.

It seem like changing the input filter to 0.20 did the trick. Now it gives me a constant reading.

I also changed from count to frequency and it gives me a more accurate reading. Which is always helpful.

Thank you everybody for your help.