Rockwell Automation 61C346 4 Input 0-10V Analog Rail Module - Manual (Page 30)

4Ć8
4.1.3 AutoMate Programming in Local Head Mode
In Local Head mode, the module is imaged in four I/O registers of the
processor. Data from all four channels is always available and will be
updated at the end of each scan. It is not necessary to select the
channel. After the I/O update, the register contains the data in the
format shown in figure 4.8.
17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 0 Octal
12 bits of converted analog data
overĆrange (1=overĆrange)
underĆrange (1=underĆrange)
not used
not used
Figure 4.8 ĆLocal Head Register Image for Input Channels
The Analog Rail module data may also be accessed in the middle of
the scan (as opposed to the end of the scan) using the appropriate
number of Analog In (AIN) blocks. The AIN block will set the
overĆrange or underĆrange bits if applicable. See section 4.1.4 for
more information about the AIN block.
Note that the AIN block is supported by the AutoMate 20E
M/N 45C224 and 45C225, but not the AutoMate 20 (M/N 45C20,
45C21, 45C220, 45C221) by APX Version 3.0.
For processors that do not support the AIN block, you can use the
MOVE block to move data in and out of the registers assigned.
OverĆrange and underĆrange bits should be used as inputs to error
coils. The I/O update will occur automatically at the end of each scan.
See Appendix C for a sample AutoMate program that reads from the
Analog Rail module without using the AIN block.