Mark V - Define the new Scale Type


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I want to add the new scale type for the Mark V's <I>.
By the GE's application manual(GEH-6195), page C-16, when I add the new scale type, defining the scale type in the scaling(*.SCA) files and "SCLEDATA.DAT" is needed.

There are 4 kinds of the scaling files (ENGLISH.SCA, METRIC.SCA, CUMSTOM.SCA and HARDWARE.SCA).

When you look at these files, the HARDWARE.SCA file is not similar to the others, i.e. Gain, Decimal Places and engineering units.

1. If defining the HARDWARE.SCA is necessary, how do you set?
2. The purpose of the CUMSTOM.SCA and the HARDWARE.SCA.


SCLEDATA.DAT is the file used by IDOS to display the engineering units and values of data on the <I>. It will either be equal to ENGLISH.SCA, METRIC.SCA, HARDWARE.SCA, or CUSTOM.SCA. Usually there is a selection on the Main Menu to switch between English and Metric display values/units, but sometimes there isn't. If there is, then (and I can't recall the exact name of the executable) SCALESET.EXE is executed with either the ENGLISH or METRIC parameter passed to it to copy the contents of ENGLISH.SCA or METRIC.SCA to SCLEDATA.DAT.

In all the years I worked on GE Mark Vs (too many to recall here) I never saw anyone use either CUSTOM or HARDWARE units, not even in the GE factory. They were created "just in case" but unless you ever use, or think you will need to use, HARDWARE units or CUSTOM units you don't need to edit these two files.

So, you've read the manual, and hopefully you've looked at the files (ENGLISH.SCA and METRIC.SCA) and got an idea of how they work and what you might need to do. I suggest even if you only use Metric or English units that you edit the other file (English or Metric, respectively), but, again, it's not absolutely necessary unless someone switches between the types often or even infrequently.

Find something in the files that is similar to what you want to create, and "copy" it. <b>Be sure to make a back-up of the file(s) before you start, so if there is any problem you can revert to the originals!</b> (The lawyers make me say that.)

When you finish using a text editor to make the changes to create the scale type you want, exit the file(s) and then simply re-start IDOS. You can do this very quickly by typing RUN_IDP at the command prompt, or just re-boot the <I>.

If you have other <I>s for this Mark V, you will manually need to copy the files you changed to the other <I>s (and "re-boot" them), or manually edit the files on the other <I>(s) to match (and then "re-boot" the <I>(s)).

Write back to let everyone know if you were successful, or if you need any further assistance.

On MKV with HMI, scledata.dat file exists but is not used because here TCI manages scaling the raw data from MKV.

In file can be included special scaling from raw data to engineering units that customer may request, other than typical conversion utilized in english or metric scaling conversion.

In file are included unscaled unit conversion - so practically no conversion. The purpose: probably for tests, when is necessary to get on the <I>/HMI displayed raw data without any conversion. For most scales are used in this file as engineering units: CNT15 and as consequence as gain is used 32768 (2power15).

When creating new scale, as the first it should be created scale in file selecting as gain the smallest value of power of 2 that is higher than expected value of the signal we want to convert. Then, using the proper conversion factor that depends on the engineering units adopted for the new scale, it should be calculated gain for file.

The file should be created even if site uses only metric engineering units.

When new scale is created, it is necessary to define this new scale also in the other scaling files: and practically as a 'place holder' in order to maintain consistency between all scaling files.
If no special scaling factor is requested, definition in file for that new scale can be the same as in the file.



Thanks for all!

I'll try it when my plant is on the overhaul.

Best regards,


If you new created unit has been used for a signal and the signal to be transmitted to the dcs (via modbus or some others protocols), you may also need to be add this new unit into the HARDWARE.TPL file. 16 bit signed two's complement representation is 32767,unsigned is 65535.