Advanced Functions - Omron H7CC-A Series Manual

H7CC-R@
Explanation of Functions
Basic Functions
Pulse Measurement Method (func)
The mode can be switched between tachometer mode and AMD-
compatible mode.
Tachometer Mode (taco)
Use this mode to measure the pulse frequency (Hz).
AMD-compatible Mode (amd)
Use this mode to measure the pulse cycle (s).
Counting Speed (cnts)
Set the maximum counting speed (30 Hz/10 kHz) for input. If contacts
are used for input signals, set the counting speed to 30 Hz.
Processing to eliminate chattering is performed for this setting.
Output Mode (totm)
Set the output method for control output based on the comparison
value.
Upper and lower limit (HI-LO), area (AREA), upper limit (HI), and
lower limit (LO) can be set. For the H7CC-RW@, the upper limit (HI-
HI) and lower limit (LO-LO) can be set. (For details on the operation
of the output modes, refer to Output Mode Settings on page 58.)
Averaging Method (avgt)
Simple averaging (SMP) or a moving average (MV) can be selected
for the averaging method.
With a moving average, the average measurement value is displayed
every sampling cycle or pulse cycle, in contrast to simple averaging,
for which the average value is displayed for the set number of
samples.
Number of Averaging Times (avgn)
Flickering display and output chattering can be prevented using
average processing. Average processing can be set to one of five
levels: no average processing, 2 times (i.e., the average of 2
measurement values), 4 times, 8 times, or 16 times.
For a measurement frequency of 5 Hz or higher using a tachometer,
the average will be equal to the sampling cycle (200 ms) multiplied by
the averaging setting (i.e., the number of times).
For less than 5 Hz, the frequency will be measured when the input
pulse comes. Average processing produces a stable display even for
fluctuating input signals. Set the optimum number of times for the
application.
If AMD-compatible mode is used, the measurement cycle will be
measured when the input pulse is received. The output will change,
however, when the comparison value is exceeded even if averaging
is enabled.
NPN/PNP Input Mode (imod)
Select either NPN input (no-voltage input) or PNP input (voltage
input) as the input format. When using a two-wire sensor, select NPN
input.
The same setting is used for all external inputs.
For details on input connections, refer to Input Connections on page
45.
52
Cycle (s)

Advanced Functions

Decimal Point Position (dp)
Decide the decimal point position for the measurement value and
comparison value.
Prescale Value (pscl)
It is possible to display the rate of rotation or the speed of a device or
machine to which the H7CC is mounted by converting input pulses to
a desired unit.
If the default prescaling value (1,000) is used, the input frequency
(Hz) will be displayed.
The relationship between display and input is determined by the
following equation. Set the prescale value according to the unit to be
displayed.
Displayed value = f × α
f: Input pulse frequency (number of pulses in 1 second)
α: Prescale value
(1) Displaying Rotation Rate
Display unit
rpm
rps
N: Number of pulses per revolution
Example: In order to display the rate of rotation for a machine that
outputs 5 pulses per revolution in the form @@.@ rpm:
1. Set the decimal point position to 1 decimal places.
2. Using the formula, set the prescale value (α) to
1/N × 60 = 60/5 = 12.
(2) Displaying Speed
Display unit
m/min
m/s
N: Number of pulses per revolution
d: Diameter of rotating body (m)
πd: Circumference (m)
• Observe the following points when setting a prescale value.
Set the set value to a value less than {Maximum countable value
− Prescale value}.
Example:
If the prescale value is 1.25 and the counting range is 0.000 to
999.999, set the set value to a value less than 998.749
(= 999.999 − 1.25).
If the set value is set to a value greater than this, output will not turn
ON.
Note: If the prescale value setting is incorrect, a counting error will
occur. Check that the settings are correct before using this
function.
Prescale value (α)
1/N × 60
1/N
Prescale value (α)
πd × 1/N × 60
πd × 1/N
d: Diameter
of rotating
body (m)