Rockwell Automation 1760-xxxx Pico Controller User Manual - Manual (Page 97)

Publication 1760-UM001D-EN-P - September 2005
Draw a Circuit Diagram with Pico 4-37
Measurement Method
The pulses on the input are counted for one second regardless of the
cycle time, and the frequency is determined. The measurement result
is provided as an actual value.
Wire a Frequency Counter
The following assignment of the digital inputs apply.
• I3 counter input for frequency counter C15.
• I4 counter input for frequency counter C16.
You only integrate a frequency counter into your circuit in the form of
a contact and enable coil. The coils and contacts have the following
meanings:
IMPORTANT
Frequency counters operate independently of the
program cycle time. The result of the actual value
setpoint comparison is only transferred once every
program cycle for processing in the circuit diagram.
The reaction time in relation to the setpoint/actual
value comparison can therefore be up to one cycle.
IMPORTANT
If you use C15 or C16 as frequency counters, coils
DC15 or DC16 will have no function. The counter
signals are transferred directly from the digital inputs
I3 and I4 to the counters. A frequency counter
measures the actual value and does not measure a
direction.
Contact Coil Description
C15 to C16 The contact switches if the actual
value is greater than or equal to the
setpoint.
CC15, CC16 Enable of the frequency counter on ’1’
state, coil activated.
RC15, RC16 Reset, coil triggered: actual value reset
to 00000.
-----------CC15
CC15--------SQ3
I8-----------
RC15