Rockwell Automation 1747-PCIS API Software - Open Controller - Manual (Page 17)

Publication 1747-UM002A-US-P - June 2000
Overview 1-5
Common Attributes of the 1746 I/O PCI Interface and 1747 Open
Controller Architectures
The functionality described in the rest of this chapter is shared by
both architectures, 1746 I/O PCI Interface and 1747 Open Controller.
The dual port is an 8K byte memory partition (optionally
battery-backed) that provides an interface between the integrated
scanner and your application software that resides on the host.
Your application (the code you develop using the API) uses the dual
port memory to communicate with the scanner to handle control
functions on the 1746 backplane, such as:
•
scanner commands and responses
•
battery and scanner status
•
scan rate frequency and timing
•
I/O image counters
•
priority messages and interrupts
•
semaphores to ensure data integrity
•
software-generated watchdogs
•
control of the 4 user-definable LEDs, the 2-position jumper, and
the 3-position switch
The scanner functionality of the dual port supports I/O control
functions, such as:
•
synchronizing scans to the application
•
forcing I/O
•
defining discrete-input interrupts
•
defining I/O module-driven interrupts (such as for the 1746-BAS
module)
•
enabling and disabling I/O slots
•
resetting I/O
IMPORTANT
On the 1747-PCIS only, the jumper for the
battery-backup dual-port memory is disabled by
default. You must switch the jumper to enable the
battery-backup feature.
The 1747-OCF dual port is NOT battery-backed.