Rockwell Automation 57C421B Pulsetach Input Module/DCS 5000/AutoMax - Manual (Page 25)

4Ć3
Counter
Value
Time
External
Latch Input
Slope is
constant at
200 kHz
Ċ Internal Counter Value
Latched Counter Value
Figure 4.3 Ć Counter Status During External Latch Mode
4.1.4 Timer Mode
Timer mode is enabled by setting the Timer/Counter Select bit
(register 5, bit 13) to one. In this mode, the module's 200 kHz clock
serves as a pulse generator which provides constant and uniform
pulses to the counter's input. When the input pulses are used in
conjunction with the external latch signals, the time interval between
two events can be measured. No external wiring is needed to use
the 200 kHz clock as a counter input. See figure 4.4.
Counter
Value
Time
External
Latch
Slope is
constant at
200 kHz
Ċ Internal Counter Value
Latched Counter Value
Figure 4.4 Ć Counter Status During Timer Mode