step7 : what is the problem with my code?

cardosocea said:

Wow... this is a first for me.

A piece of code shows up on PLCtalk that I am 99% sure I know the author of.

Is the system called SoftSpeed or SoftTorque? I recognize the DB numbers and naming... the name of the program gives away the other clues.

Click to expand...

No this is not soft torque, i am studying the original program and using some blocks from there to simulate one by one by copy and paste from there to understand how the program works. my program is very simple but the original program has some function blocks which i can use in mine

now when i turn pot value changes from 1-100 in step of 10
but the value is shown as 10,20,30 and not as 1.00e01,2.00e01,3.00e01
what is the difference, the data type is real why the representation is different

can it make any difference to the program?

The value is actually shown as 30.0, not 30. Therefore it is in floating point format. The e representation only appears if the value is higher than a certain number (can't remember which right now).

Good luck with your Top Drive.

Yes this is a program to control a top drive which has two DC motors . the problem is that the torque output is not precise and needs to be fixed.

How did you measure actual torque?

I have not been to site but from the information conveyed to me they used a calibrated torque tube and found a 10% difference in what they set and what they get, so i was looking into the program how that can be fixed because the motor have a current to torque curve and if i am giving motor x amps of current it will output fixed amount of torque which can be determined from the curve

if i can manipulate the signal sent to the DC current producing unit called SCR then i believe it can be fixed, i think the scaling is not right . in scaling block it is using a constant which is fixed, i intend to vary the values of this constant depending on the pot values slightly to make a more accurate scaling.

Not trying to be funny... but who installed the calibrated torque test tube? Because the fact it is calibrated means nothing if the installation isn't correct and a slight angle can make a difference in the torque reading.

I've had this in the past and it was simply ridiculous as it was clear the tool wasn't installed correctly and the drive was (in my view) far more precise than that tool would ever be in that condition.

Obviously, with SCR's you'll only have a read out of current which can be translated to torque.

i have been told that there is no angle associated with this torque tube this things holds the pipe in the center and it is very accurate and no angle is involved,the angle is of concern when they use another equipment called Torque tong, well i am not a mechanical engineer but i have the info that this measurement is not prone to error because of angle as it does not apply to this mode of measurement.

Don't know the amount of time you've worked with or around offshore drilling, but in general you simply can't trust anything they say.
I don't know the people you're working with but after 9 years in that industry on both client and supplier side, unless I see it, I don't believe it.

I agree. Will update when i visit site.