Linespeed: Map % to PPM

LeDude · Feb 14, 2013

Hello there,
steadily learning here with a bunch of SLC 5/04's. AB is new country for me, and I thought I'd ask for some help.

I am currently working on a project, where operators type in a percentage, which is a MAGIC UNIT (according to the programmer).

This percentage is scaled to an analog output, which controls a hydraulic pump, which then propels a conveyor and applies glue on paper ( I guess a 100hp e-motor was too big

). The speed is measured in PPM ( parts per minute).

Minimum PPM and Target PPM are already on the SLC.

So what I am trying to do here is:

Map this % to the PPM. I have a minimum line speed and a target speed.

Idea here is, that the conveyor ramps up to minimum speed (let's say 50% = 500PPM)
But target speed is 700PPM. They type in 700 and the machine ramps up.

So How can I map the speed, that when they type in Target Speed 700PPM, it speeds up to that PPM?

I don't want to use that % as line speed unit, I want actual PPM as unit.

And at 700PPM, but only once reached that number, I want the OP to be able to run faster than that if he wants to.

HMI is an AB Panelview 1000.

THis is rather simple, but my lack of experience makes this more complicated than it probably is.

Thanks for your help, guys.

Lancie1 · Feb 17, 2013

So How can I map the speed, that when they type in Target Speed 700PPM, it speeds up to that PPM? ...which is a MAGIC UNIT (according to the programmer).

The programmer is trying to pull a joke on you - there are no magic PLC solutions. The PLC program has to take your "700" PPM and convert it to a number that your controlling device (Hydraulic Pump Variable Speed Drive, or Hydraulic Pump pressure controller) will understand, such as Speed in Hertz, or Pressure in PSI. That is done for the Allen Bradley SLC 5/04 PLC with a scaling computation, usually the SCP instruction, as described in the Help file:

SCP [Scale with Parameters]
Rockwell Software
Description
This output instruction consists of six parameters. Parameters may be integer, floating point, or immediate data values or addresses containing values. The Input value is scaled to a range determined by creating a linear relationship between input min and max values and scaled min and max values. The scaled result is returned to the address indicated by the output parameter.

Entering Parameters
Input - Enter a value to be scaled. This can be a word address or an address of floating point data elements.

Input Min - Enter a minimum value for the input (low end of range). This value can be a word address, a long (double-word) address, an integer constant, floating point data element, or a floating point constant.

Input Max - Enter a maximum value for the input (high end of range). This value can be a word address, a long (double-word) address, an integer constant, floating point data element, or a floating point constant.

Scaled Min - Enter a minimum scaling value representing the low end of the range to which you want to scale the input. The scaling relationship is linear. The value can be a word address, a long (double-word) address, an integer constant, floating point data element, or a floating point constant.

Scaled Max - Enter a maximum scaling value representing the high end of the range to which you want to scale the input. The scaling relationship is linear. The value can be a word address, a long (double-word) address, an integer constant, floating point data element, or a floating point constant.

Output - Enter an address for the scaled value that is returned after the instruction is executed. This value can be a word address, a long (double-word) address or an address of floating point data elements. If any floating-point file types or floating-point constants are encountered in the above parameters, then the entire instruction is treated as floating point, and all immediate integer data values are converted to immediate floating-point data values.

LeDude · Feb 18, 2013

Yea,
those Magic Units made me laugh.
I will look into your suggestion.
I know I can write 20 rungs or just find the right instruction to make it short. And that's where I rely on guys like you!

Thanks

Linespeed: Map % to PPM

LeDude

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Lancie1

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LeDude

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