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How to Change the Voltage / Current / Power Units Displayed on the ION Meters

Issue
The front panel display on the meter automatically scales to display voltage, current, and energy readings in appropriate units. The displayed units cannot be changed because they are based on the CT / PT ratios. 
The User Guide mentions these 'Automatic Units' but does not explain how to change the CT / PT ratios to obtain the desired units.

Product Line
ION 8800, 8650, 8600, 8500, 8400, 8300.
ION 7650, 7600, 7550, 7500
ION7400
PM8000

Environment
Changing scale on meter.

Cause
The meter automatically scales the reading to the appropriate units; sometimes this is not desired as the precision of the reading may be lost.
The meter assumes that the user has entered the correct PT and CT ratio range for the desired scaling unit.  

Resolution
Option 1:

To change the way the meter scales voltage, current and power, adjust the PT or CT primary parameters as follows:

For Voltage and Current  
V or A: Make PT or CT Primary < 1000
   
kV or kA: Make PT or CT Primary within 1000 to 1,000,000
   
MV or MA: Make PT or CT Primary > 1,000,000
   
For Power  
W: (CT*PT*3/1000) < 1000
  (CT*PT) < 333,333
   
kW: 1000 < (CT*PT*3/1000) < 1,000,000
  333 < (CT*PT) < 333,333
   
MW (CT*PT*3/1000) > 1,000,000
  (CT*PT) > 333,333


NOTE: After scaling the PT PRIMARY, also scale the PT SECONDARY appropriately.

Example: 
If the actual PTs are 4160:120 and you want to display kV instead of V (i.e. 4.26 KV) set PT PRIMARY to 416 and PT Secondary to 12.

NOTE:
- If these changes are made from the front panel, note that you will have to do each one separately.  During this time the meter will calculate 'wrong' values. 

For example, using the case above, if you first changed the PT primary to 416, and then changed the secondary to 12, as soon as you make the first change (but before you make the second) the effective PT ratio becomes 416:120.  The calculated values in the meter for volts, power and energy will be 1/10th their actual values.  This is corrected as soon as you make the change to the secondary value.  This will affect the following functions (and maybe a couple others as well):

- Voltage and Power Minimums will likely drop to 1/10th their nominal levels

- Sag/Swell module will 'detect' a drop in voltage, trigger a waveform capture and create an event which will alarm in ION/SPM/PME.
This can be avoided by first disabling the sag/swell detection (either in Vista, or from the front panel by setting the Nominal Voltage to zero before making any other changes).

- Any Setpoints configured for voltage, current or power could be triggered.
- If the changes were performed using ION Designer, all parameters can be changed simultaneously, avoiding the mentioned effects.

Option 2: 
Connect the outputs of the power meter module to an arithmetic module, where the input = output, and pass the required values (Voltage, Current etc.) through the arithmetic module. The values on the output of the arithmetic module can then be linked where necessary, such as the display module or Power Monitoring Expert Vista diagrams:

For Example:

Kindly follow the steps below to change your energy scale units from Kilo to Mega:
Step 1: Scale the energy value, using a custom arithmetic module

  1. In ION Setup, click on the Device that you want to set up.
  2. Click on the View Setup Options Only tab from the tool bar.
  3. While holding on the Ctrl key, left click on your meter to go into the Advanced Setup view mode
  4. Click on Arithmetic module.
  5. In the right hand window, right click in an empty space and select Insert Module.
  6. A new module will appear among the list of existing modules. Right click on this new module and rename it (give it a name you can easily remember, e.g. Egy Mega Scale) and click on send.
  7. Double click on this new module and in the inputs tab, select Source 1 and click on Edit.
  8. In the new window, scroll to the Integrator Modules and select the energy parameter you want to link to Source 1.
  9. Repeat this step for all the energy values you want to scale down for Source 2 to Source n. (Depending on how many energy values you want to scale)
  10. If you have more values than the available sources, you can add another arithmetic module and add them in there.
  11. After adding your sources, click on the Setup registers tab.
  12. Divide each source value (S1) by 1000 to convert the kilo value to mega. (i.e. S1/1000 and so on for each respective source)
  13. After entering the formulas, click on the Output Registers tab and select each output value, and rename it accordingly (i.e. MWh del, MVARh del, MVAh del…and so on)
  14. Click on Send.

 


Step 2: Link the output of the custom arithmetic module to the display module:
NOTE: You can add the scaled vales to a new display module, or you can edit the default module to include the scaled values.
To add a new module:
  1. In the Advanced Setup View mode, click on the Display Modules.
  2. In the right hand window, right click in an empty space and select Insert Module.
  3. A new module will appear among the list of existing modules. Right click on this new module and rename it (give it a name you can easily remember, e.g. Energy del Mega) and click on send.
  4. In the Setup Registers tab, configure the Screen type, Softkey Number, softkey name and Screen Title
To use an existing Module (not recommended, so as not to change default configurations)
  1. Select the Energy Del folder for energy Delivered and Energy Rec for Energy Received.
  2. In the Setup Registers tab, configure the Screen type (depends on the number of parameters you want to view), Softkey Number, Softkey name and Screen Title
Configuring the registers
  1. Double click on this module and in the inputs tab, select Source 1 and click on Edit.
  2. Scroll to the Arithmetic Modules and select your output values from the custom arithmetic module (i.e. the outputs from Egy Mega Scale).
  3. Repeat the step for all the sources you want to display.


 


Note: Auto scaling can be avoided with this procedure however the units such as A, V, kA, kV will be lost for parameters that go through the arithmetic module and are eventually displayed on the screen.

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