
42213 Sarah Way, Temecula, CA 92590,
USA 

Tel: 8008548530 (USA)
Tel: 9516992437
Fax: 9516957246
sales@electronumerics.com 

Micro Series Frequency,
Rate
& Period Meters
With dual, independently fieldscalable
channels
Features
Standard Counter
 Available in three digit heights:
0.56" for panel mounting,
1.0" (Mighty1)
or
5.0" (Mighty5) for
longdistance viewing.
 Two independently fieldscalable
channels selected by front panel pushbutton
 Frequency from 0.005 Hz to
1 MHz
 Inputs from NPN or PNP proximity
switches, contact closures, digital logic, magnetic pickups down to 12 mV, or AC inputs up
to 250 Vac
 6digit resolution at update
rates up to 25/s
 Line frequency measurement to
60.0000 in a few line cycles
 Selectable "count by"
of 10 or 100 with rounding
 Square root extraction
 Isolated 5, 10 or 24 Vdc
excitation supply to power sensors
 Green or red LED display
 Choice of isolated plugin
options for control and computer interface:
dual
relays,
420 mA & 010
V analog output,
RS232/485 serial I/O,
low voltage AC & DC power

1/8 DIN
case environmentally sealed to NEMA4X from front panel.
 1/8 DIN
version certified to UL 31011, CAN/CSAC22.2,
EN 610101 (CE Mark).
Extended
Counter
All capabilities
of the Standard Counter, plus:
 Rate and total simultaneously.
 Custom curve
linearization.
 Arithmetic functions
applied to two channels: A+B, AB,
A*B, A/B, A/B1 (draw).

Description
The
Micro dualchannel frequency, rate and period meter is a basic
operating mode of the Micro counter with the FR signal conditioner board. It can
display frequency from 0.005 Hz to 1 MHz, rate in engineering units, and period (inverse of
frequency). The normal displayed value can range up to 999,999 counts. Above that level,
the display will flash and go into fourdigit XXXXEX scientific notation. Square root
extraction is standard. Each
channel (A or B) may be independently scaled for frequency, rate or period. The displayed
channel is selected via a front panel pushbutton.
Examples of applications are the accurate display of AC
line frequency, RPM, speed from proximity switch inputs, and flow from turbine flowmeter
inputs.
Fast, High Resolution Measurement
The Micro frequency /
rate meter determines
frequency by timing an integral number of periods over a specified gate time, and then
taking the inverse of period. Rate is obtained by multiplying the input by a scale factor.
The inverse period approach allows greater accuracy and faster update times than
conventional meters which count signal pulses over a specified time interval. AC line
frequency may be accurately measured to 50.0000 or 60.0000 Hz in a few line cycles. 1000 Hz
signals may be measured to 0.01 Hz resolution at up to 25 readings per second. Fast response is
ideal for alarm and control applications.
To reduce the effects of signal noise, a count
by 10 or 100 feature with rounding is selectable. Variations in the displayed reading can
also be reduced by selecting a longer gate time. An adaptive filter can reduce variations
due to noise while rapidly responding to actual changes in the signal.
Extended Counter
Capabilities
An Extended counter
version provides capabilities beyond those of the standard counter:

Rate and total simultaneously.
One
channel can display total while the other displays rate. The selection for either channel
is via a front panel pushbutton. This mode is ideal for flow applications when the same
signal is applied to both channels.

Custom curve
linearization. Exceptionally
accurate custom curve linearization allows linearization of the low end of
turbine flowmeters. For setup, up to 240 data points can be input into a spreadsheet or
text file by the user. The computer then calculates nonlinear segments, which are
downloaded into the meter via RS232. The Extended version allows linearized rates to be
totalized.

Arithmetic functions. The
Extended counter makes arithmetic functions available, namely A+B, AB, A*B, A/B and A/B1
(draw). For example, A+B allows two input flows to be summed for total flow, while AB
allows outflow to be subtracted from inflow for net flow. If transducers with a frequency
output are used, A*B allows horsepower to be displayed based measured torque and RPM, or
based on force and velocity. A/B can be used for the proper mixing of ingredients, while
A/B1 (draw) is used to compare rates for stretching or tensioning.
Universal Signal
Conditioner
The dualchannel signal
conditioner accepts inputs from proximity switches with PNP or NPN output, TTL or CMOS
logic, magnetic pickups, contact closures, lowlevel outputs from turbine flow meters down
to 12 mV, and highlevel AC line inputs up to 250 Vac.
A
builtin isolated 5, 10, or 24 Vdc excitation supply can power proximity switches and
other sensors, thus eliminating the need for an external power supply.
Other Features and Options
Plugin
isolated analog
output, dualsetpoint
controller, and RS232/485 serial communications boards can upgrade Micro
and Mighty Series meters
from standalone monitor to system interface and control. With the
optional analog output board, a Micro frequency / rate meter can serve
as a 010 V or 420 mA transmitter.
Micro Series
instruments can be powered from
95240 Vac ±10% and 95370 Vdc, or
optionally from 1234 Vac and 1048 Vdc.
Any setup functions and front panel keys may be locked out for
simplified usage and security. The popular
1/8
DIN version with 0.56" high digits is environmentally sealed to
NEMA4X (IP65) from the front when panel mounted, and is
available with red or green LEDs.

Specifications
Display 
Readout
Digit Height
Color
Range
Indicators 
6 digits, 7segment
Available with 0.56", 1.0", 4.0" or 5.0" digits.
High brightness red. Green available with 0.56" digits.
999999 to +999999,
XXXXEX scientific notation beyond 999999
Four LED lamps 
Inputs 
Types
Grounding
Channel A Frequency
Channel B Frequency
Selectable Hysteresis
Rolloff Filter
Debounce Time 
AC, pulses from NPN, PNP transistors, contact closures, magnetic pickups
Common ground for channels A & B
0.005 Hz to 1 MHz
0.005 Hz to 250 kHz
12 mV to +12 mV, +30 mV to +60 mV, 30 mV to 20 mV,
150 mV to +150 mV, +350 mV to +600 mV, 600 mV to 350 mV,
1.15 V to +1.15 V, +1.25 V to +2.1 V, 2.1 V to 1.25 V
Selectable: 1 MHz, 30 kHz, 250 Hz
Selectable: 0, 3, 50 ms 
Conversion 
Frequency Technique
Conversion Time
Gate Time
Timeout
Output & Display Updates 
Inverse period
Gate time + 30 ms+ 02 signal periods
Selectable 10 ms to 199.99 s
Selectable 10 ms to 199.99 s
Same as conversion time 
Accuracy 
Time Base
Span Tempco
Longterm Drift 
Crystal
calibrated to ±2 ppm
±1 ppm/°C (typ)
±5 ppm/year 
Power 
Voltage,
std.
Voltage, opt.
Frequency
Power isolation 
95240 Vac ±10% and 95370 Vdc
1234 Vac and 1048 Vdc
DC or 49440 Hz
Safetyrated to 250 Vac, meter ground to earth ground,
DC to 60 Hz, 4.2 kVp per High Voltage Test 
Excitation Output 
5
Vdc
10 Vdc
24 Vdc
Output isolation 
5
Vdc ±5%, 100 mA max
10 Vdc ±5%, 120 mA max
24 Vdc ±5%, 50 mA max
50 Vdc to meter ground 
Environmental 
Operating
Temperature
Storage Temperature
Relative Humidity
Protection 
0°C to 60°C
40°C to 85°C
95% at 40°C, noncondensing
NEMA4X (IP65) when panel mounted 
Electrical Connections 

Typical
Applications 
AC Line Frequency 

The Micro frequency meter will accept line voltages up to 250 Vac and
display line frequency to 6digit accuracy (50.0000 or 60.0000) in a few line cycles. Fast
low frequency response is achieved by timing the period and taking its inverse.

RPM and Speed 

The Micro frequency meter can sense the lowlevel signals from magnetic
pickups or the NPN or PNP transistor output of active sensors. These can be powered
directly by the meter. Display in RPM in tachometer mode or rate in units of speed is achieved by mathematically
scaling the meter. 
Flow Rate and Simultaneous Total 

The Micro frequency / rate meter is compatible with all flow
meters which
generate pulses at a frequency proportional to flow rate. The Extended version can display
scaled rate or total for the same input at the push of a button, and alarm from both the
rate and total. The Extended version can also linearize flow transducers so as to extend
their dynamic range. 
Combining Two Rates 

The Extended Micro frequency / rate meter offers A+B, AB and A/B arithmetic
functions. A+B allows two input flows to be summed for total flow, while AB allows
outflow to be subtracted from inflow for net flow. Flow ratios aid in the proper mixing of
ingredients 
Custom
Curve Linearization 

The Extended Micro frequency / rate meter can linearize the output
turbine flow
meters, which tend to be nonlinear on the low end. Linearizing improves the
dynamic range and accuracy of turbine flow meters. 
Systemlevel Capabilities 
The Micro dual channel
rate meter can independently scale, display and alarm two pulse input channels. All signal
or alarm data can further be transmitted via RS232 or RS485, including peak readings and
arithmetic combinations of the two rates. The displayed rates can also be transmitted as
an isolated 420 mA analog output. 

Micro & Mighty Series Downloads
