
42213 Sarah Way, Temecula, CA 92590,
USA 

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

Micro Series A/B Ratio
&
A/B1 Draw Meters
Arithmetic functions A+B,
AB, A*B, A/B, A/B1 applicable to rate
or total
Extended Counter
 Available in three digit heights:
0.56" for panel mounting,
1.0" (Mighty1) or
5.0" (Mighty5) for
longdistance viewing.
 A/B and A/B1 (draw) arithmetic
functions.
 Applicable to rate or total.
 Frequencies from 0.005 Hz to
1
MHz.
 Independent scaling for each
channel.
 Inputs from NPN or PNP proximity
switches, contact closures, digital logic,
magnetic pickups down to 12 mV, or AC inputs up
to 250 Vac.
 Update rates to 25/s.
 Selectable "count by"
of 10 or 100 with rounding.
 Isolated 5, 10 or 24 Vdc
excitation supply to power sensors.
 Green or red 6digit 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
version environmentally sealed to NEMA4X from front panel.
 1/8 DIN
version certified to UL 31011, CAN/CSAC22.2,
EN 610101 (CE Mark).

Description
The A/B ratio and
A/B1 draw meters are selectable operating modes of the Micro counter with Extended counter
main board and FR dualchannel signal conditioner board.
Ratio can be used to
compare flow rates in two channels, the RPM of rollers or gears, or the speed of moving
machinery, such as conveyor belts. Ratio can also be applied to scaled totals to compare
two batches to be mixed. In this application, one meter is used to monitor the ratio of
flow rates, and a second meter to monitor the resulting batch totals.
Draw is obtained by
subtracting 1 from ratio. Draw is often used to measure the elongation or shrinkage of
material as it passes between rollers, or to monitor variation in the speed of rollers for
tensioning.
Ratio and draw are similar, except that 1 is
subtracted from ratio to obtain draw. The frequency of channels A and B is first measured
and is then converted to rate in engineering units by multiplying it by the appropriate
scale factor for that channel. Either rate can be displayed. The A/B ratio is then taken
mathematically by the meter, and 1 is subtracted for draw. The result can be multiplied by
a multiple or 10 from 0.0001 to 100000, and the decimal point can be set to display the
result with the desired precision up to six digits.
Fast, High Resolution
Measurement
The
Micro counter
determines frequency by timing an integral number of periods over a programmable gate
time. The inverse period approach allows greater accuracy and faster update times than
conventional meters which count signal pulses over a specified time interval.
Channel A accepts pulses from 0.005 Hz to
1
MHz, while Channel B accepts pulses from 0.005 Hz to 250 kHz. At the minimum gate time of
10 ms, update rates can be up to 25/second. Such fast response is ideal for peak capture
and for alarm and control applications. Variations in the displayed reading can be reduced
by selecting a longer gate time. An adaptive filter can further reduce variations due to
noise while rapidly responding to actual changes in the signal.
Universal Signal Conditioner
The
Micro
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. Jumper
selections provide optimum operation for different sensor types and noise
conditions. A builtin isolated 5, 10, or 24 Vdc
excitation supply can power proximity switches and other sensors, and eliminate the need
for an external power supply.
Other Features & Options
Plugin
isolated analog
output, dual setpoint controller,
and
RS232/485 serial communications boards can
upgrade Micro and Mighty Series meters from standalone monitoring to system interface and control.
Micro Series
meters 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
Signal Ground
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,
1.15V to +1.15V, +1.25V to +2.1V, 2.1 V to 1.25V
Selectable: 1 MHz, 30 kHz, 250 Hz
Selectable: 0, 3, 50 ms 
Conversion 
Frequency Technique
Conversion Time
Gate Time
Max Signal Wait Time
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 Temp.
Storage Temp.
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 
Controlling the Mixing Ratio of Two Fluids 

Displaying and alarming the input flow rate ratio of two
fluids (gas or liquid) allows these to be mixed in a predetermined ratio in continuous
processes. The sensing element is normally a turbine flowmeter, which outputs pulses at a
frequency proportional to flow rate. The A/B ratio can also be displayed for totalized
rate (or delivered volume). 
Comparing Fluid Inflow & Outflow 

The ratio of the inflow and outflow rates of a tank is a
measure of the relative filling or emptying rate. The same meter can also be programmed to
display the net inflow or outflow rate in flow units, or to display totalized inflow our
outflow in volume units. Any of these parameters can be alarmed using the dual relay board
and be transmitted via 420 mA, RS232 or RS485. 
Controlling Coating Thickness on a Film 

In this application, Channel A measures the rate at which
a coating material is applied, as measured by a flow meter, while Channel B measures the
speed of the film based on pulses from a proximity switch. Displaying and alarming the A/B
ratio assures that an even thickness of coating material is applied as the speed of the
film is varies. 
Synchronizing Two Conveyor Lines 

The dualchannel Micro counter can measure the speed of
conveyor lines by using the output of proximity switches which sense gear teeth or spokes
of rotating drive wheels. Displaying the speed ratio of two lines allows line speeds to be
adjusted so that material arrives at work stations when needed. 
Measuring Draw for Elongation 

Draw (Ch A / Ch B  1) can be used to display the elongation of films
compressed between rollers, the shrinkage films, and the RPM difference of rollers whose
speed is varied to maintain tension. The sixdigit resolution of the Micro dual channel
counter / rate meter is ideal for comparison of rates that are close to each other. 
Micro & Mighty Series Downloads
