ABB ACS880 Series, Firmware Manual

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Sending process PID feedback and setpoint values through EFB
The drive also has storage parameters for incoming process PID feedback ( 40.91
Feedback data storage ) as well as a process PID setpoint ( 40.92 Setpoint data
storage ). The feedback storage parameter is selectable in the source selection
parameters 40.8 Set 1 feedback 1 source and 40.9 Set 1 feedback 2 source .
The corresponding parameters in process PID control set 2 (group 41 Process PID
set 2 ) have the same selections.
￭ Register addressing
The address field of Modbus requests for accessing holding registers is 16 bits.
This allows the Modbus protocol to support addressing of 65536 holding registers.
Historically, Modbus master devices used 5-digit decimal addresses from 40001
to 49999 to represent holding register addresses. The 5-digit decimal addressing
limited to 9999 the number of holding registers that could be addressed.
Modern Modbus master devices typically provide a means to access the full range
of 65536 Modbus holding registers. One of these methods is to use 6-digit decimal
addresses from 400001 to 465536. This manual uses 6-digit decimal addressing
to represent Modbus holding register addresses.
Modbus master devices that are limited to the 5-digit decimal addressing may
still access registers 400001 to 409999 by using 5-digit decimal addresses 40001
to 49999. Registers 410000 to 465536 are inaccessible to these masters.
Note: Register addresses of 32-bit parameters cannot be accessed by using 5-digit
register numbers.
About the control profiles
A control profile defines the rules for data transfer between the drive and the
fieldbus master, for example:
• if packed boolean words are converted and how
• how drive register addresses are mapped for the fieldbus master.
You can configure the drive to receive and send messages according to the ABB
Drives profile or the Transparent profile. With the ABB Drives profile, the embedded
fieldbus interface of the drive converts the control word and status word to and
from the native data used in the drive. The Transparent profile involves no data
conversion. The figure below illustrates the effect of the profile selection.
Fieldbus control through the embedded fieldbus interface (EFB) 713