ABB ACH580 Series - Page 99

90 ACH580 E-Clipse bypass and packaged drive user manual
Embedded fieldbus
Mailbox read/write
The ACH580 provides a “Mailbox” function to access parameters that have not been
pre-defined by the protocol. Using mailbox, any drive parameter can be identified
and read. Mailbox can also be used to adjust parameter settings by writing a value to
any parameter identified. The following table describes the use of this function.
Actual value scaling
When using Modbus, the scaling of actual values is set by the parameter resolution.
(Refer to the Parameter list and descriptions section in the ACH580 HVAC control
program firmware manual (3AXD50000027537) for parameter resolutions.) For
example:
Name Description
Protocol Reference
Modbus
1)
N2 BACnet
Mailbox
Parameter
Enter the number of the drive group and
parameter number using the format:
(group #) * 256 + parameter #.
Example: drive parameter 28.01 is entered as
(28 * 256) + 1 = 7169
Does not
apply.
AO19 AV25
Mailbox Data Contains the parameter value after a read, or
enter the desired parameter value for a write.
AO20 AV26
Mailbox Read A binary value triggers a read – the value of
the “Mailbox Parameter” appears in “Mailbox
data”.
BO19 BV15
Mailbox Write A binary value triggers a write – the drive
value for the “Mailbox Parameter” changes to
the value in “Mailbox data”.
BO20 BV16
1) Modbus provides direct access to all parameters using the format: 400000 + (group #) * 256
+ parameter #.
Example: drive parameter 28.01 is mapped as 40000 + 28 * 256 + 1 = 407169.
Feedback Integer Scaling (Feedback Integer) / (Scaling) = Scaled Value
100 (example: 12.11 AI1 actual
feedback)
1000 = 1 unit 100 / 1000 = 0.1 mA
10 10 = 1% 10 / 10 = 1%