Rockwell Automation Publication 1769-IN088A-EN-P - February 2011 101
I/O Memory Mapping Chapter 3
Word 6 and 7 status bits are defined as follows:
• Sx = General status bit for channels 0 through 5. This bit is set (1) when an
error (over- or under-range, open-circuit, or input data not valid) exists for
that channel. An input data not valid condition is determined by the user
program. This condition occurs when the first analog-to-digital
conversion is still in progress at power-up or after a new configuration has
been sent to the module. Refer to the RTD/resistance Input Module User
Manual, publication number 1769-UM005
, for details.
• OCx = Open-circuit detection bit for channels 0 through 5. These bits are
set (1) when either an open or shorted input for RTD inputs or an open
input for resistance inputs is detected.
• Ux = Under-range flag bits for channels 0 through 5, using RTD inputs
only. These bits can be used in the control program for error detection.
There is no under-range error for a direct resistance input, because 0 is a
valid number.
• Ox = Over-range flag bits for channels 0 through 5, using either RTD or
resistance inputs. These bits can be used in the control program for error
detection.
Configuration Data File
The manipulation of the bits from this file is normally done with programming
software, such as RSLogix 500, RSLogix 5000, or RSNetWorx for DeviceNet,
during initial configuration of the system. In that case, graphical screens are
provided by the programming tool to simplify configuration. However, some
systems, like the 1769-ADN DeviceNet adapter, also allow the bits to be altered
as part of the control program, using communication rungs. In that case, it is
necessary to understand the bit arrangement. Refer to the Compact RTD/
resistance Input Module User Manual, publication number 1769-UM005
for
additional details.
Words 0…5 of the configuration file allow you to change the parameters of each
channel independently. For example, word 0 corresponds to channel 0 and word 1
corresponds to channel 1. The functional arrangement of the bits is shown below
for a single word/channel.
Short-circuit detection for resistance inputs is not indicated
because 0 is a valid number..
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