Rockwell Automation 1772-LV Mini-PLC - 2/15 Programmable Controller (Series B) Programming and Operations - Manual (Page 166)

Troubleshooting Aids
Chapter 13
13Ć2
Bit monitor lets you display the status of all 16 bits of any data table word. It
can function when the processor is in any mode. By pressing [SEARCH][5][3]
(key sequence of word address), the status of all 16 bits of the desired word will
be displayed. While the cursor is in the word address filed, use the [
→
] and [
←
]
keys to change address digits.
The status of the 16 bits in the next highest or next lowest word address also can
be displayed by pressing the [
↑
] or [
↓
] keys, respectively. Bit monitor also can
display the status of force conditions.
Force Functions
There are two types of force functions:
Force on
Force off
You can use the force functions to selectively force an input bit or output bit on
or off. The processor must be in the test or run/program mode.
The force functions determine the on/off status of input bits and output bits by
overriding the I/O scan. You can use an input bit on or off regardless of the
actual state of the corresponding input device. However, forcing an output bit
will cause the corresponding output device to be on or off regardless of the rung
logic or the status of the output image table bit.
NOTE: When in test mode, the processor will hold outputs in their last state
regardless of attempts to force them on, even through the output bit instructions
will be intensified.
Forcing functions can be applied in either of two ways using:
Bit manipulation/monitor display of an I/O word
Ladder diagram display of user program
By pressing [SEARCH][5][3] (key sequence of address), you can display the bit
status and force status of the 16 corresponding input bits or output terminals of
the desired word. use the [
→
] and [
←
] keys to cursor to the desired bit. Or, in
the ladder diagram display, forcing can be applied by placing the cursor on an
examine or energize instruction. In either case, after positioning the cursor, you
can use any one of the following key sequences for placing or removing a
forced condition:
[FORCE ON] [INSERT]
[FORCE OFF] [INSERT]
[FORCE ON] [REMOVE]
[FORCE OFF] [REMOVE]
Bit Monitor Function