Metering Input (Release 3.3 and Prior)
- Nina Cardillo (Unlicensed)
- Nina Cardillo
For SmartServer 3.4 and higher, see Metering Input.
There are two models of the IOX, one with built-in metering and one without. You can use the metering version of the IOX to monitor power and energy consumption of a one-to-three phase power mains circuit. To monitor power and energy with an IOX, you must first connect a current transformer (CT) per phase to the CT inputs of the IOX. You must also connect each of the phases to be monitored to the line input of the IOX. By default, the IOX is configured for a 3-phase circuit and CTs that output 333mVAC for a 5A load, which is a 5A/333mV CT ratio.
This section describes how to configure the IOX for use with 1, 2, or 3 phases and how to configure for different CT ratios. This section also describes the data reported by the IOX and consists of the following:
Configuring the Number of Phases
You can configure the IOX meter for use with 1, 2, or 3 phase circuits. By default, the IOX meter is configured for a 3-phase system.
To configure the number of IOX meter phases with the CMS Datapoint Browser widget, perform the following steps:
Open the Datapoint Browser.
Note: To best view all of the information on this widget, click the Expand button (
). 
- Set the Datapoint Browser device filter (
) to show the IOX meter device.
The first installed IOX meter will be iox1.meter, the second will be iox2.meter, and so on.
- Click the Action button (
) for the cpPhaseEnable datapoint and select the Edit Value action.
The view to enable L1, L2, and L3 phases appears.
- Set the value to 1 to enable a phase, or 0 to disable a phase.
- Click SAVE to store the phase enable changes.
Configuring the CT Ratio
You can configure the IOX meter current-measurement scaling factor. By default, the IOX meter is configured for a current transformer (CT) that outputs 333.3mVAC for a 5A load. This is a 5A / 333.3mV CT ratio. The 0 – 333.3mV range is fixed. You can change the 5A multiplier to match current measured by your CT when it reports 333.3mV.
To configure the CT ratio with the CMS Datapoint Browser, perform the following steps:
Open the Datapoint Browser.
Note: To best view all of the information on this widget, click the Expand button (
). - Set the Datapoint Browser device filter () to show the IOX meter device.
The first installed IOX meter will be iox1.meter, the second will be iox2.meter, and so on. - Click the Action button () for the cpCtRatio datapoint and select the Edit Value action.
The view to set L1, L2, and L3 current transformation ratios appears.
- Set the cpCtRatio datapoint L1_ctRatio.multiplier, L2_ctRatio.multiplier, and L3_ctRatio.multiplier values equal to the load current at 333.3mV for the respective phase. The default value is 5 for a 5A / 333.3mV CT ratio.
- Click SAVE to store the CT ratio settings.
Reading Meter Data
You can monitor accumulated energy and instantaneous measurements report by the IOX meter.
The following IOX meter accumulated energy datapoints are available:
Datapoint Name | Measurement Units | Description |
nvoActiveEnergy | Wh | Total present active energy for all enabled phases. |
nvoAppEnergy | VA | Total present apparent energy for all enabled phases. |
nvoPhaseActEnergy | Wh | Present active energy by phase. |
nvoPhaseAppEnergy | VAh | Present apparent energy by phase. |
nvoPhaseRctEngery | VAhr | Present reactive energy by phase. |
nvoReactEnergy | VAhr | Total present apparent energy for all enabled phases. |
The following IOX meter instantaneous measurement datapoints are available:
Datapoint Name | Measurement Units | Description |
nvoCurrentRMS | A | RMS current by phase. |
nvoPhaseActPwr | W | Active power by phase. |
nvoPhaseAppPwr | VA | Apparent power by phase. |
nvoPhaseFrequency | Hz | Frequency by phase. |
nvoPhaseReactPwr | Var | Reactive power by phase. |
nvoPower | W | Total power for all enabled phases. |
nvoPowerStatus | pf | Average power factor for all enabled phases and by phase. Power factor is equal to active power / apparent power. The datapoint includes quadrant and THD fields that are not used. |
nvoVoltageAvg | VAC | Average voltage for all enabled phases. |
nvoVoltageRMS | VAC | RMS voltage by phase. |
To monitor the IOX meter datapoints with the CMS Datapoint Browser, follow these steps:
Open the Datapoint Browser.
Note: To best view all of the information on this widget, click the Expand button (
). - Set the Datapoint Browser device filter () to show the IOX meter device.
The first installed IOX meter will be iox1.meter, the second will be iox2.meter, and so on. - Set the browser polling rate to 1 second to update one displayed datapoint per second.
- The Datapoint Browser displays the meter datapoints.
Refer to the Metering Input (Release 3.3 and Prior)#tables shown above for the displayed Datapoint Name and description of the value.