Allen-Bradley 1747-OC Series, User Manual

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1747-UM001A-US-P - March 2000
1-8 Introducing the Open Controller
Software not using the APIs
Software that does not use the open controller APIs must be modified to
find the 1747-OCF scanner and retrieve the assigned resources. Sample
code that performs this function is available upon request from Rockwell
Automation Technical Services.
Hardware
differences
The following features of the 1747-OCE are either not present on the
1747-OCF, or are implemented differently.
Battery backup of dual-port memory
The dual-port memory is battery backed on the 1747-OCE. It is not battery
backed on the 1747-OCF.
Scanner reset
The controller CPU has the ability to reset the local I/O scanner. This
function is implemented differently in hardware on the 1747-OCF than on
the 1747-OCE. The difference is transparent to users of the DOS or NT
APIs. Software not using the APIs (or NT device driver) must be modified.
Sample code which performs this function is available upon request from
Rockwell Automation Technical Services.
Real-time clock SRAM
The 1747-OCE includes 4K bytes of static RAM within the real-time clock.
This SRAM is not available on the 1747-OCF.
The following API functions will return an error if used with the 1747-OCF:
OC_ReadRtcSRAM
OC_WriteRtcSRAM
Static RAM
The 1747-OCF includes 512K bytes of battery-backed static RAM. This
SRAM is not available on the 1747-OCE.
The following NT API functions are available for the 1747-OCF only, and
will return an error if used with the 1747-OCE:
Important: You must write the output image data into the dual-port register
before changing your open controller to scan mode. We
recommend that you do this for both the 1747-OCE and the
1747-OCF