AutomationDirect DL205 User Manual

DL205 User Manual, 4th Edition, Rev. D
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Chapter 3: CPU Specifications and Operations
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During the Service Peripherals portion of the scan, the CPU analyzes the communications
request and responds as appropriate. The amount of time required to service the peripherals
depends on the content of the request.
CPU Bus Communication
Some specialty modules can also communicate directly with the CPU via the CPU bus. During
this portion of the cycle the CPU completes any CPU bus communications. The actual time
required depends on the type of modules installed and the type of request being processed.
NOTE: Some specialty modules can have a considerable impact on the CPU scan time. If timing is critical in
your application, consult the module documentation for any information concerning the impact on the scan
time.
Update Clock/Calendar, Special Relays, Special Registers
The clock, calendar, and special relays are updated and loaded into special V-memory locations
during this time. This update is performed during both Run and Program Modes.
Writing Outputs
The time required to write the output status for the local and expansion I/O modules depends
on which CPU you are using and the number of output points in the base. The following table
shows typical update times required by the CPU.
For example, the time required for a DL240 to write data for two 8-point output modules
would be calculated as follows (where NO is the total number of output points):
Formula
Time = 33 + (NO x 14.6 µs)
Example
Time = 33 + (16 x 14.6 µs)
Time = 266.6 µs
Timing Factors DL230 DL240 DL250–1 DL260
Overhead
66.0 µs 33.0 µs 28.1 µs 28.1 µs
Per output point
8.5 µs 14.6 µs 3.0 µs 3.0 µs
Modes DL230 DL240 DL250–1 DL260
Program Mode
Minimum 8.0 µs fixed 35.0 µs 11.0 µs 11.0 µs
Maximum 8.0 µs fixed 48.0 µs 11.0 µs 11.0 µs
Run Mode
Minimum 20.0 µs 60.0 µs 19.0 µs 19.0 µs
Maximum 26.0 µs 85.0 µs 26.0 µs 26.0 µs
To Service Request DL230 DL240 DL250–1 DL260
Minimum
260µs 250µs 8µs 8µs
Run Mode Max.
30ms 20ms 410µs 410µs
Program Mode Max.
3.5 Seconds 4 Seconds 2 Seconds 3.7 Seconds

AutomationDirect DL205 Specifications

General

Brand	AutomationDirect
Model	DL205
Category	Controller
Language	English