Hitachi NJI-350B manual Preload input operation, Current value clear instruction operation

Chapter 8 High-speed counter, PWM / Pulse train output and Analogue I/O

Others

7] The user program can switch from using a counter as an up counter to a down counter, as well as from a down counter to an up counter while the counter is operating (using FUN142).

*The counter output does not turn on unless the control output flag (R7FC to R7FF) is turned on.

(2)Preload input operation

When a preload signal is entered, the current counter value is reset to the preload value.

The counter output is controlled only when the on-preset value or off-preset value is exceeded by the progress of the counter value. Because of this, the counter output maintains its status before the preload input when the on-preset or off- preset value is exceeded due to the preload value (when jumping from the Off area to the On area, or vice versa). Also, the status of the counter output is reflected in the data memory at the timing of the refresh process. Therefore, it should be noted that the status monitored by peripheral units, etc. and the actual output status may be different (by a delay of one scan).

Preload input Preload input

FFFFH

Off preset

Preload value

On preset

0000H

Coincidence ON

output OFF

Preload input

Preload input

Figure 8.6 Preload input operation of high-speed counter (single-phase)

(3)Strobe input operation

When a strobe signal is entered, the current counter progress value is stored in the strobe storage area (WRF07A to 7D) of the special internal output.

(4)Current value clear instruction operation

When the current value clear instruction (FUN144) is executed, the current counter value is reset (cleared) to zero. The counter output is controlled only when the on-preset value or off-preset value is exceeded by the progress of the counter value. Because of this, the counter output maintains its status before the execution of the current value clear instruction when either the on-preset or off-preset value is exceeded due to the execution of the current value clear instruction (when jumping from the Off area to the On area, or vice versa).

Current value clear Current value clear

FFFFH

Off preset

On preset

0000H

Coincidence ON output

OFF

Figure 8.7 Current value clear instruction operation of high-speed counter (single-phase)

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