ABB ACH580 Series User Manual page 99

90
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.
Name
Mailbox
Parameter
Mailbox Data
Mailbox Read
Mailbox Write
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.
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:
100 (example: 12.11 AI1 actual
feedback)
10
Embedded fieldbus
Description
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
Contains the parameter value after a read, or
enter the desired parameter value for a write.
A binary value triggers a read – the value of
the "Mailbox Parameter" appears in "Mailbox
data".
A binary value triggers a write – the drive
value for the "Mailbox Parameter" changes to
the value in "Mailbox data".
Feedback Integer
ACH580 E-Clipse bypass and packaged drive user manual
Scaling (Feedback Integer) / (Scaling) = Scaled Value
1000 = 1 unit 100 / 1000 = 0.1 mA
10 = 1% 10 / 10 = 1%
Protocol Reference
1)
Modbus N2
AO19
Does not
AO20
apply.
BO19
BO20
BACnet
AV25
AV26
BV15
BV16