Adapter Module I/O Update Rate With The 1756-Dhrio Module In The Local Chassis - Allen-Bradley ControlLogix User Manual

Adapter Module I/O Update Rate with the 1756-DHRIO Module in
the Local Chassis
When the 1756-DHRIO module resides in the same chassis as the
owner-controller, updated output data (refreshed to new values via the
control program) is delivered to the adapter module at:
RPI + scan rate per adapter * number of adapters
Where the RPI is equal to the value determined from the graphs on
page 10-6, and scan rate per adapter=3ms @ 230.4K, 5ms @115.2K,
or 8ms @57.6K.
The updated input data is delivered to the Logix5550 at:
Scan rate per adapter * number of adapters
The update rate for an adapter module (i.e. the rate at which I/O data
is produced/consumed between the owner-controller and the
1756-DHRIO module) is:
RPI + 2[Scan rate per adapter * number of adapters]
This is a turnaround calculation for an output to input in the
same rack.
When you include block transfers, the update rate for an adapter
module is:
RPI + 2(Scan rate per adapter * number of adapters) + (Scan
rate per adapter * total number of adapters with BT modules
in them)
Remote I/O Operation
Publication 1756-6.5.14 - August 1998
10-7