English to Metric


marc sinclair


England is metric! and has been since the introduction of SI units in the early 1970s.

I guess you mean imperial units, like the barleycorn, inch, foot and yard. If so, then why convert? use all one or all the other.

Marc Sinclair
what do you mean by unable to convert? just type English or Metric in TCI control panel properties then re-boot your HMI...


Michael Griffin

In reply to marc sinclair - The Americans don't use imperial. They use something which they commonly call "english", which would probably more properly be called "american". The two systems are to some degree related, but they are not the same.

Compared to imperial, the sizes of some of the "english" (american) units are the same, while some units have the same name but are different sizes. In some cases the differences in the sizes of the units are small enough that they can be ignored for most (but not all) purposes. In other cases though the differences are very large. This also means that the *relationships* (conversion factors) between different types of units within the imperial versus within the "english" (american) systems are not the same either.

So far as I know, the Americans were (are) the only ones to use "english" (american) measures. Any of the rest of the world that used yards, feet, and inches (etc.) used imperial measures (although most if not all of those have long since adopted SI). It may be possible though that some former or current American colonies are using "english" (american) measures. In most (if not all) countries that use or used imperial measures, the American system is not recognised as valid (which can have implications when used in the sale of goods).

As for why someone may wish to convert units in an MMI panel, some machines allow you to select the system of measure for numeric parameters, and it is up to the user to select the one they need. Usually however, this is accomplished by working in SI units in the machine logic, and converting to or from imperial (or "english") for display and data entry purposes only. I'm not aware of an ordinary MMI panel which does these calculations for you though.
Some GE Mk V HMIs had a menu selection to change scale types from English [sic] to Metric; some didn't.

It is believed that some early GE Mk V HMIs required something similar to how scale types were changed in the <I>/IDOS manner, as follows:

Exit to a command (DOS) prompt and change to the unit-specific directory (e.g., F:\UNIT1 for Unit 1) and type the following command:


This is to save a copy of the current SCLEDATA.DAT file to a "back-up" for safe-keeping.

Then type the following command to copy the metric scale code data file to the "master" scale code information file.


(You may be prompted about overwriting the existing SCLEDATA.DAT file; answer Y[es] to overwrite.)

Next you will need to stop CIMPLICITY, stop TCI, then re-start TCI, wait approximately 60 seconds after re-starting TCI, then re-start CIMPLICITY (or, just re-boot the GE Mk V HMI).

To return to English [sic] units, just copy ENGLISH.SCA to SCLEDATA.DAT (answer Yes when prompted to overwrite the existing file) and stop CIMPLICITY, stop TCI, re-start TCI, and wait for an appropriate period of time before re-starting CIMPLICITY (or just re-boot the GE Mk V HMI).

Let us know if this works! If it doesn't, you'll likely need to copy SCLEDATA.SAV back to SCLEDATA.DAT....


marc sinclair

Yes, and they lose out, probably more than they know. I recently attended a meeting where it was decided to buy Italian (effluent) screens rather than US made, simply because of the 'non standard' nuts and bolts.


Michael Griffin

In reply to marc sinclair - In the automation market, many components are only available in SI sizes. That is, many multinational companies do not offer parallel product lines in both SI and "english" (or imperial) sizes. It is very difficult to build a machine these days without using at least some SI sized components.

What this means is that if you are considering buying an American made machine or assembly, you have to look closely at the fastener types they used. Some of the better ones will use strictly SI types throughout the machine. Some however will mix fastener (or air fitting) types. Mixing fastener types is a very bad thing, as sooner or later you will have to disassemble the machine for service or repair (or some other reason), or replace a screw, etc. Inevitably, the fasteners or fittings will get mixed up and the threads (or the cap screw heads) damaged. This can get very expensive and add to a lot of down time (and hacked up repair jobs).

Mixing fastener sizes on the same machine is usually considered a sign of incompetent designers. Sometimes it can't be avoided because of third party components for which there is no substitute. Sometimes it can't be avoided because the customer insisted on it. For run of the mill applications though, insisting on SI sizes throughout the machine is a lot more maintenance friendly. There's not much that can be done about older machines in the same plant, but at least don't mix things up within the same machine!

This of course doesn't even begin to deal with the really expensive mistakes some people have made because the product designs are in millimetres (as in the entire auto industry) while the production machines to assemble them were designed in inches.