GENERAL DESCRIPTION
The Gemini 4000 series (4100 & 4200) instruments are two input
microprocessor based dual function counter/rate or dual counter instruments.
The 6-digit display features 0.56" high LEDs with negative sign, overflow and
displayed value indicators (A & B) located to the left of the display. When
programmedasacounter/rateinstrument,theAindicatorwillbeonwhentherate
is displayed and the B indicator will be on when the count is being displayed.
Pushing the “+/-” button toggles the display between the counter and rate or the
two counters depending on the personality selected.
TheGemini4000series consistsoftwobasic units,asingle presetversion,the
Gemini 4100, and a two preset version, the Gemini 4200. Each basic unit is also
availablein115/230VACversions,withorwithoutSerialcommunicationsanda
relay board. The 20 mA current loop option (serial communications) makes
possible remote or computerized monitoring or control of the Count, Presets and
Scale Factors.
Flexibility and usefulness are insured through user programmability. With
simplefrontpanel keystrokesand rearpanelswitch settings,anyoneofa number
of configurations can be selected. Once the selection is made, all or part of the
keyboard can be disabled to protect the settings and guarantee that no unwanted
changes can occur during the measurements.
Eachtimethepower isturnedoff, theunitautomaticallysavesthe settingsand
data in its special no power memory. When power is restored, the Gemini sets
itself back to the operational modes and restores the data it had at power down.
The “no power” E2PROM’s life expectancy is at least 100,000 cycles of power
being applied to and removed from the unit.
Whenever the power comes on, the Gemini performs a series of internal
diagnosticsto verifytheintegrity ofthestored data.Thereis alsoaself-testmode
and a “watchdog” timer to help prevent processor lockup.
The Gemini 4000 series counters can accept bi-directional, uni-directional, or
quadrature signals. They also have the capability to double or quadruple
(Quadrature x4) the resolution of the incoming count signal. A separate input
mode is available to make the counter/rate or dual counters completely
independent of each other.
Oneinputprovides the signalforrateor a counterandthe other inputprovides
the signal for a counter. An anti-coincidence add/subtract mode is also provided
to obtain a difference between two input signals.
Each channel features separate scaling and decimal point placement for
readout in different units or at different resolutions.
A Counter Load feature enables the operator to modifythe count value under
circumstances that occur when flawed material has been counted and it is
necessarytoadjustthecountvalueaccordingly.TheCounterLoad featurecan be
“locked out” in applications where it is not required.
The Rate Indicator portion uses a time interval method (1/tau) to calculate the
rate value. This method enables high resolution at all rates. The unit counts input
pulses and after a programmable minimum update time has occurred, it waits
until the next edge occurs, takes the elapsed time and number of edges, and
calculates the rate value. At slower rates, averaging can be accomplished by
programming the “Rate Minimum Update Time” (0.5 sec. to 16 sec.) for the
desired response. Extensive scaling capabilities allow practically any desired
reading at very slow count rates.
For maximum flexibility, the Gemini’s output(s) can be assigned to either the
rate or count channels or one to each. When in dual counter mode, the output(s)
can be assigned to the Counter B channel. For the Gemini 4200, one can be
assigned to Counter A and the other to Counter B.
The relay(s) are mounted on a plug-in board which makes it easy to field
upgradeyourGemini.Thecontactsareratedfor240VACor28VDCat5amps.
The construction of the Gemini features a metal, die cast bezel for maximum
durability with high quality appearance. The sealed front panel meets NEMA
4/IP65 specifications for washdown and/or dust, when properly installed.
Electrical connections are made with removable, plug-in terminal strips at the
rear of the unit. Clamp-type pressure plate terminals accept stripped #14 AWG
wire without lugs.
SAFETY SUMMARY
All safety related regulations, local codes and instructions that appear in the
manual or on equipment must be observed to ensure personal safety and to
prevent damage to either the instrument or equipment connected to it. If
equipment is used in a manner not specified by the manufacturer, the protection
provided by the equipment may be impaired.
Donotuse this unit todirectlycommandmotors,valves, or otheractuatorsnot
equipped with safeguards. To do so, can be potentially harmful to persons or
equipment in the event of a fault to the unit.
