Control.com - Nerds in Control

Hi,
I have a puzzle with units displayed in HMI. We defined an English unit of a point in IO.asg, which is 'C_C_MAI02 AFPBD DPH2O; C -CTBA-040 Cprsr bellmouth differential press transmitter [PT-147],' and we also defined the range in IOCFG, which is 0~61inH2O, something like below:

TCCA Card Definition - Socket 1 - Screen 4/7                  

                 

Milliamp Input Definitions   1 - 8                        

                            

Signal CDB value CDB value CDB value EnableEnable     

in use Full Scale at 4 mA  at 20 mA Low diag High diag

             

Signal1:YES 512   -40.0      40.0   NO       NO      

Signal2:YES 512    0.00      61.0   NO       NO   

But the value of AFPBD displayed in Rung Display is 347, as well as in Main.cim, however the unit is mmH2O, it is right? How does the Mark V or HMI transfer the unit from inH2O to mmH2O to display? I am not sure if I describe the question clearly.

The Mark V turbine control panel *processors* know *nothing* about the scaling of points. All of the data in the Mark V is "raw" count data (for example, 0-65535, or -32768 - 32767); the Mark V doesn't know if the operator interface (<I> or GE Mark V HMI) is displaying data with Metric or English or Custom or Hardware engineering units, the Mark V just does all of it's data calculations and manipulations with raw counts.

All of the scaling of the data for display of *live data* on the operator interface is handled by the operator interface (<I> or GE Mark V HMI). When live data for a point comes back from the Mark V, the operator interface checks to see which units are being used to display the point data (Metric or English) and converts the raw counts to the desired engineering units. You could have two operator interfaces, one configured to display values with Metric engineering units and one configured to display values with English engineering units, both connected to the same Mark V turbine control panel, and they each request the data for a point from the Mark V which sends the values as raw counts to the operator interface, which then scales it for the engineering units it is configured for and displays the information on the screen.

When you are working in .ASG files you can use Metric scaling information or English scaling information (though I wouldn't suggest mixing them). When the file is compiled, the compiler knows how to convert that scale information to raw count format for use by the Mark V turbine control panel processors. When you are working in a .ASG file, you are not seeing live data, you are only configuring the point. When the file is compiled, that scaling information is converted to raw count format for use by the Mark V turbine control panel.

When you are working in the I/O Configurator, you are not seeing live data for points, you are only configuring the point, and you must use English units (for most applications) to configure the point. Again, when the information entered into the I/O Configurator is compiled (when you click on "Save and Exit") it is converted into a format that the Mark V can use for raw count data for the I/O points. The Mark V turbine control panel processors do all of their data processing using raw counts, and send raw count data back to the operator interface. When the operator interface is displaying live data, it converts the raw counts into engineering units chosen for that operator interface.

Essentially, when you are configuring a point using either Metric or English engineering units, that information is converted to a format which the Mark V can use for handling the data in raw counts. The operator converts raw counts for live data into the chosen engineering units for the *display* of the live data values. So, when you are configuring points, you can make the configuration in any engineering units you wish (for the most part), because the compilers will appropriately convert that information in raw count format because the Mark V only uses raw counts when processing data. When the operator interface is displaying live data values, it converts the raw data from the Mark V into the chosen engineering units for that operator interface.

In the <I>, SCLEDATA.DAT is the file that the <I> uses to determine which engineering units to use. When someone changes the engineering units, it's done by executing SCALESET.EXE with either METRIC or ENGLISH units (or CUSTOM or HARDWARE), which copies the contents of the specified file to SCLEDATA.DAT, and that's how the <I> knows which engineering units to convert to from the raw count data from the Mark V.

That's why there is a scale type 42 in METRIC.SCA and in ENGLISH.SCA; 13005 mmH2O is the metric equivalent of 512.0 inH2O. These two values are just the maximum values any signal which is assigned scale type 42 can have: 13005 mmH2O for Metric and 512 inH2O for English units of Differential Pressure, Water Column (DPH2O).

As for the values you put into the I/O Configurator for the milliamp input, you have to tell it the Maximum scale value (for scale type 42, scale code DPH2O), that would be 512.0 (since the I/O Configurator needs English units). So, for the 4.0 mA value you would put 0.0 (inH2O, which is implied), and for the 20.0 mA value you would put 61.0 (inH2O, implied). (By the way, 61.0 inH2O would be approximately 1550 millibar, I believe.)

In the GE Mark V HMI, CIMPLICITY is involved in the conversion of raw counts; actually it probably involves TCI and CIMBRIDGE. This was never very well documented for the GE Mark V HMI.

But, I'm not really clear on the problem you're having. Are you changing the scaling of 96BD from what it was originally? Is the GE Mark V HMI not displaying the value properly?

When you made the assignment in IO.ASG, you're choosing scale code DPH2O, which is scale type 42 in any of the .SCA files. When you make an assignment in IO.ASG, you need to know what the max scale value to enter into the I/O Configurator, which would be 512.0 for DPH2O (scale type 42).

How do I know the unit scaling of each point when I open the I/O configurator? Yes, as you said, the I/O configurator use English unit scaling, but for anyone point in I/O configurator something like MA input, it will can be inH2O or PSI or inHg and so on, what is it used for that point in I/O configurator?

The answer everyone seeks regarding scaling are contained within GEH-5980. Only one scaling file may be used at any given time. Start in section 6-6.

The HMI runs a suite of software called TCI. Among many other things, TCI provides scaliing for any real value that needs to be displayed. The scale factors are stored in files with names like english.sca and metric.sca in the Unit directory. There can be other sca files in this directory. You can specify which scales to use by opening the Turbine Interface applet in the control panel and changing the Default Scale. Next time you restart TCI (and then CIMPLICITY, the scales will be changed. However, the engineering unit labels on the screen will not change. You will have to use the Signal Manager to re-import the points, which will then pick up the new engineering unit labels.

Thanks all, now I understand how to define the scaling of IOconfigurator. Actually the problem was that we downloaded the earlier IO_cfg file in which the range is -20~+20. As we did not use the same HMI to download the IO_cfg, the two HMIs were not synchronized, so there is a little bit different setting between the two HMIs.

We changed the IO range setting base on the data sheet, which has a range of 0~1500mmbar, so all the ranges should be the same including the transmitter, IOconfigurator in Mark V, maybe also in HMI. That is why I asked the question here. Thank you very much again.