Control through the embedded fieldbus interface 345
Actual values for the ABB Drives profiles
Both the ABB Drives classic profile and ABB Drives enhanced profile support the use
of two fieldbus actual values, ACT1 and ACT2. The actual values are 16-bit words
each containing a sign bit and a 15-bit integer. A negative value is formed by
calculating the two’s complement from the corresponding positive value.
The drive signals are scaled before written into fieldbus actual values, ACT1 and
ACT2. Parameters 50.04 FBA ref1 modesel and 50.05 FBA ref2 modesel both select
the drive actual signals and define the scaling as follows:
• If you select value Speed, the drive actual signal 01.01 Motor speed rpm
is scaled
and written to the fieldbus actual value. The scaling is as follows:
• If you select value Raw data, the drive parameters 50.06 FBA act1 tr src
and
50.07 FBA act2 tr src select the drive values for fieldbus actual value ACT1 and
ACT2. The table below shows the scaling.
Value of 01.01 Motor speed rpm [rpm] Corresponding fieldbus actual value
ACT1 or ACT2 [integer]
value of parameter 19.01 Speed scaling 20 000
00
-(value of parameter 19.01 Speed scaling) -20 000
Drive value Corresponding fieldbus actual value
ACT1 or ACT2 [integer]
k × 0.5
(k = value of parameter 58.11)
32 767
00
k × -0.5
(k = value of parameter 58.11)
-32 768