The user-definable LHMI LED object is also visible as IEC 60870-5-103 Class 1 data. In older IED versions, the LED object had only two positions: Off and Alarm (red). The corresponding IEC 60870-5-103 Class1 LED data area shows DPI values off, “01” for Off and values on, “10” for Alarm.
In the new LED versions, the IED LED objects can be configured to use several options and colors. By default, the LED states are defined as Off, OK (green) and Alarm (red). However, the color definition for the OK and Alarm states can be configured.
Two IEC 60870-5-103 LED protocol data area alternatives are available depending on how the LEDs are used.
Example 1
If the LEDs are configured to show two positions, for example Off-OK or Off-Alarm, the LED object positions are visible in the digital input LED area 1 with DPI values off “01” for Off and on “10” for OK or Alarm. This coding is the same as in the older IED versions.
Example 2
If LEDs are configured to show all three positions or the two positions OK-Alarm, LED area 2 can be used. LED area 2 data are by default configured to show all the three possible LED state values in the extended DPI data octet. This resembles the coding of double-pole objects. The possible values are “00” for None, “01” for OK and “11” for Alarm.
In case of a two-position “OK-Alarm” LED, the LED area 2 data can be configured to show normal Off/On DPI-data using the double-point extended value to single-point value conversion. This means that the actual DPI LED values are converted as 00-to-10, 01-to-01, (10-to-10), 11-to-10. Thus, the LED state OK (“01”) is shown as value “01” (Off) and state Alarm (“11”) as value “10” (On).
| LED Pos | LED area 1 DPI data | LED area 2 DPI data | Three states determination |
|---|---|---|---|
| Off | OFF | - | Area1 = Area2 = OFF |
| OK | ON | OFF | Area1 <> Area2 |
| Alarm | ON | ON | Area1 = Area2 = ON |
The two IEC 60870-5-103 LED areas are updated in parallel. LEDs can be configured individually. The most suitable IEC 60870-5-103 LED data object for each case can be chosen.