Publication 1734-UM003A-EN-P - August 2000
1-2
About the Very High Speed Counter Modules
The 1734-VHSC has 2 outputs that access customer power from the
PointBus to facilitate various output device’s voltage requirements.
The outputs are rated to source 0.5A at 10 to 28.8V dc. The output
may be tied to an input. This lets you cascade counters of multiple
1734-VHSC modules. The counter has 4 user-selectable On-Off values
(i.e. windows) associated with it. Either output may be tied to any or
all of the window signals.
Operating Modes
The very high speed counter modules operate in the following modes:
•
Counter Mode - read incoming single phase pulses, return a
binary count.
•
Encoder Mode - read incoming 2 phase quadrature pulses,
return a binary count.
•
Period/Rate Mode - count internal clocks during the On period,
return a frequency. Outputs updated
only at the end
of the
period.
•
Continuous/Rate Mode - count internal clocks during the On
period, return a frequency. Outputs are updated
continuously
during the period.
•
Rate Measurement Mode - read pulses during the sample period,
return a frequency.
•
PWM Mode (pulse width modulation) - generate a pulse width
modulated signal.
The operation of the counter and encoder modes is nearly identical.
The difference between the two modes is in the type of feedback (1
phase vs. 2 phase) for the count direction (up or down). In
encoder
mode
, a transition is expected on B for counting to proceed in a
direction, whereas, in
counter mode
, the B input may be left at a
static level.
All operating modes are selected by writing appropriate configuration
data to the module.
Counter Mode
The counter mode reads incoming pulses and returns a binary
number (0 - 16,777,215
max
) to the PointBus. The counter mode only
accepts
single phase
inputs. The module determines the Phase B
input state, and counts up or down accordingly.
Channel A input is used as the counting pulse while channel B is used
to determine the direction.
Summary of Contents for POINT I/O 1734-VHSC24
Page 1: ...Very High Speed Counter Module Cat No 1734 VHSC5 and VHSC24 User Manual ...
Page 22: ...Publication 1734 UM003A EN P August 2000 1 14 About the Very High Speed Counter Modules ...
Page 48: ...Publication 1734 UM003A EN P August 2000 4 8 Configuring Your Very High Speed Counter Module ...
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