Allen-Bradley micrologix 1500, Руководство пользователя

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Publication 1764-UM001A-US-P
Using Trim Pots and the Data Access Tool (DAT) 5-7
5. Press ENTER to load the new data. Press ESC or INT/BIT to discard the new
data.
F1 and F2 Functions
The function keys, F1 and F2, correspond to bits and can be used throughout the
control program as desired. They have no effect on bit or integer monitoring.
Each key has two corresponding bits in the DAT function file. The bits within the
DAT function file are shown in the table below.
F1 or F2 Key Pressed
The pressed bits (DAT:0/F1P and DAT:0/F2P) function as push-buttons and
provide the current state of either the F1 or F2 key on the keypad. When the F1 or
F2 key is pressed, the DAT sets (1) the corresponding pressed key bit. When the F1
or F2 key is not pressed, the DAT clears (0) the corresponding pressed key bit.
F1 or F2 Key Latched
The latched bits (DAT:0/F1L and DAT:0/F2L) function as latched push-buttons
and provide latched/toggle key functionality. When the F1 or F2 key is pressed, the
DAT sets (1) the corresponding latched key bit within the DAT Function File.
When the F1 or F2 key is pressed a second time, the DAT clears (0) the
corresponding latched key bit.
Working Screen Operation
Because the DAT is a communications device, its performance is affected by the
scan time of the controller. Depending on the user program, if a long scan time is
encountered and the DAT waits for information from the controller, a working
screen is displayed. The working screen consists of three dashes that move across
the display from left to right. While the working screen is displayed, key presses are
not recognized. Once the DAT receives data from the controller, it returns to its
normal mode of operation.
If you encounter excessive working screen conditions, you can minimize the effect
by adding an SVC instruction to the control program. Refer to the
MicroLogix
NOTE
If the data is protected or undefined, pressing the up/down key
scrolls to the next element in the list.
Key Bits Address Data Format Type User Program Access
F1 Key Pressed DAT:0/F1P Binary Status Read/Write
Latched DAT:0/F1L Binary Status Read/Write
F2 Key Pressed DAT:0/F2P Binary Status Read/Write
Latched DAT:0/F2L Binary Status Read/Write
AB Spares