IMD 100 Integration manual 4189360015 Rev. G
Units conversion
Page 185 of 243
10.4
Converting current values
All current measurements unscaled values. In order to convert current measurements to Ampere it is
necessary to scale the values by using the following register values:
•
I device (reg. 0xC6, value in 0.1 A). This value is used in internal calculations in the IMD.
•
Current 200 pct. (reg. 0xD9). This value is a scaled in raw values and used in internal calculations
in the IMD.
10.4.1 Converting current raw values to Ampere
To convert any current reading from the IMD, such as CurrentActual (0x20), CurrentAllowedMax
(0x24) and so on, use the following formula (the actual current reading is named ActualReading):
𝐶𝑢𝑟𝑟𝑒𝑛𝑡 𝐴 𝑅𝑀𝑆 =
𝐼 𝐷𝑒𝑣𝑖𝑐𝑒 ∗ 𝐴𝑐𝑡𝑢𝑎𝑙𝑅𝑒𝑎𝑑𝑖𝑛𝑔 ∗ 2
𝐶𝑢𝑟𝑟𝑒𝑛𝑡 200𝑝𝑐𝑡 ∗ 10
Example of converting a reading from the IMD of 300:
600 ∗ 300 ∗ 2
1287 ∗ 10
= 27.97
300 units
≈ 28 A
RMS
ActualReading
=
300
I Device (0xC6)
= 600
Current 200pct (0xD9)
= 1287
10.4.2 Converting Ampere to current raw values
To convert any current value in Ampere to its representation in raw values use the following formula
(the actual current reading is named “Current A RMS”):
𝐶𝑢𝑟𝑟𝑒𝑛𝑡 𝑢𝑛𝑖𝑡𝑠 =
𝐶𝑢𝑟𝑟𝑒𝑛𝑡 𝐴 𝑅𝑀𝑆 ∗ 𝐶𝑢𝑟𝑟𝑒𝑛𝑡 200𝑝𝑐𝑡 ∗ 10
𝐷𝑒𝑣𝑖𝑐𝑒 𝑑𝑒𝑠𝑖𝑔𝑛 𝑐𝑢𝑟𝑟𝑒𝑛𝑡 ∗ 2
Example of converting a current value of 30:
30 ∗ 1287 ∗ 10
600 ∗ 2
= 321.75
30 A
RMS
≈ 322 units
Current A RMS
=
30
I Device (0xC6)
= 600
Current 200pct (0xD9)
= 1287
Info
It is recommended to read the
I device and Current 200 pct at start up and use these
values in the conversion.
Info
It is recommended to read the
I device and Current 200 pct at start up and use these
values in the conversion.