Rockwell Automation 1747-PCIS2 PCI Bus Card - Manual (Page 9)

PCI Bus Card for 1746 Local I/O 9
Publication 1747-5.31–April 1998
General Operation
The scanner is a PCI Bus card that is installed in a PC. It scans 1746 I/O
modules via the 1747-PCIC cable and adapter. The scanner can
communicate to any 1746 I/O module.
The application program on the PC will provide the software driver to
initialize and control the scanner. Once the scanner is running, it
continuously retrieves all the input data from the 1746 I/O modules and
places the data in dual port memory on board the scanner. Output data is
constantly sent from the same dual port memory to the 1746 I/O modules.
Calculating Scan Time
Scan time represents the elapsed time it takes your scanner to retrieve
input data from all I/O modules and place it in dual port memory on the
scanner one time.
Add the rows in the following tables to calculate input and output scan
times. Fill in the shaded boxes. All times are in microseconds.
Estimate Minimum Input Scan Time
Quantity Fixed Scan
Time Total
Digital I/O Modules:
number of class 0 input words: X 48 =
Specialty I/O Modules (Class 1)
number of 1746-BAS modules (class 1):
number of 1746-NIO4V modules:
number of 1746-FIO4V modules:
number of 1746-NI4V modules:
X 490 =
X 265 =
X 265 =
X 325 =
Specialty I/O Modules (Class 3 and 4)
number of 1746-HSCE modules:
number of 1747-SN modules:
number of 1746-BAS modules (class 4):
X 712 =
X 1185 =
X 650 =
Forced Input Overhead
number of class 0 input words:
number of specialty input words:
number of specialty I/O modules:
X 6 =
X 9=
X 30 =
Input Scan Overhead (Add this time to the total from the I/O modules) 36
Minimum Input Scan Time (total)