88  Communication profiles        
References
References are 16-bit words containing a sign bit and a 15-bit 
integer. A negative reference (indicating reversed direction of 
rotation) is formed by calculating the two’s complement from the 
corresponding positive reference.
ABB drives can receive control information from multiple sources 
including analog and digital inputs, the drive control panel and a 
communication module (for example, FEPL-02). To have the drive 
controlled through the fieldbus, the module must be defined as the 
source for control information, for example, reference.
Scaling
References are scaled as shown below.
Note: The values of REF1 MAX and REF2 MAX are set with drive 
parameters. See the drive manuals for further information.
In ACSM1, ACS850, ACQ810 and ACS880, the speed reference 
(REFx) in decimal (0…20000) corresponds to 0…100% of the 
speed scaling value (as defined with a drive parameter, eg, 
ACS880 parameter 46.01 Speed scaling).
In ACS355, drive parameter REFx MIN may limit the actual 
minimum reference.
DriveFieldbus
0 
REFx MAX / Speed scale
-(REFx MAX) / Speed scale
0
REF2: -10000
REF1: -20000
REF2: 10000
REF1: 20000