Lockout Feature - GPI GM Serie Guía De Operaciónes

Setting the High (20 mA) Endpoint
1.. Start.the.fluid.pumping.system..Set.it.for.steady.flow.
at.the.highest.anticipated.rate.(or.the.rate.at.which.
you.want.a."maximum".indication).
2.. Wait.while.the.fluid.flow.is.uninterrupted.for.at.least.
10.seconds.
NOTE:..If.you.observe.the.current.loop.after.completing.
the. procedure,. it. should. be. registering. at. or. very.
near.20.mA.(within.the.resolution.specifications.for.
the.present.conditions).
3.. While. watching. the. transmitter's. indicating. light,.
press. and. hold. both. its. "SET". and. "20". buttons..
Release.them.when.the.light.blinks.
NOTE:..During.the.high.and.low.setpoint.procedure,.if.
the.new.settings.are.very.different.from.the.previous.
settings,.it.is.possible.to.reverse.the.4.mA.and.20.mA.
setpoints.so.that.the.4.mA.frequency.is.higher.than.
the.20.mA.frequency..The.situation.corrects.itself.
after.you.complete.both.setpoints..If.the.new.settings.
are.close.to.the.previous.settings,.you.may.safely.
set.either.the.low.and.high.settings.independently.

Lockout Feature

This.transmitter.includes.a.user.selectable.lockout.fea-
ture..Select.the.feature.after.setting.the.4.and.20.mA.
endpoints. during. initial. use.. The. lockout. feature. pre-
vents.tampering.with.the.4.and.20.mA.settings.on.the.
transmitter.
Before.activating.the.lockout.feature.make.sure.there.
is.no.signal.being.received.by.the.transmitter..If.signal.
is.being.received,.deactivate.it.by.one.of.the.following.
methods:
•. Stop.the.flow.through.the.line.that.is.being.recorded.
•. Disconnect.the.output.device.on.the.flowmeter.
Locking / Unlocking the Transmitter
Position.yourself.so.you.can.easily.operate.the.pushbut-
tons.on.the.transmitter..You.should.be.able.to.see.the.
indicator.light.
To. lock. the. transmitter,. use. the. pushbuttons. to. enter.
the.following.sequence.with.a.brief.pause.between.each.
button.press:..20.–.20.–.20.–.SET...The.indicator.light.
will.blink.twice.to.indicate.the.unit.is.locked.
To.unlock.the.transmitter,.use.the.pushbuttons.to.enter.
the.following.sequence.with.a.brief.pause.between.each.
button.press:..4.–.4.–.4.–.SET...The.indicator.light.will.
blink.once.to.indicate.the.unit.is.unlocked.
Checking the Status of the
Lockout Feature
To.check.the.status.of.the.transmitter,.use.the.pushbut-
tons.to.enter.the.following.sequence.with.a.brief.pause.
between.each.button.press:..SET.–.4.–.20.–.SET...The.
indicator.light.will.blink.once.if.unlocked.or.twice.if.locked.
Optional 0-20 mA Mode
A.few.current.loop.systems.use.0-20.mA.output..The.
input.signal.frequency.of."0".produces.an.output.analog.
signal.of."0".with.direct.proportionality.and.no.offset..
NOTE:..A.true.loop.current.of."0".in.a.loop.powered.de-
vice.like.the.GPI.transmitter.is.not.obtainable..That's.
because. the. current. loop. powers. the. transmitter,.
and.its.operating.current.is.non-zero.even.at.zero.
frequency. input.. In. 0-20. mode,. the. GPI. 4-20. mA.
Transmitter's.loop.current.will.drop.to.as.near.zero.
as.possible.at.zero.input,.in.most.units.between.1.
and.2.mA..
Procedure
1.. To.enter.0-20.mode,.simply.press.and.hold.all.three.
pushbuttons.simultaneously.(4,.SET.and.20).at.any.
flowrate.. Continue. holding. until. the. indicator. light.
blinks.(light.will.blink.in.up.to.5.seconds).and.release.
all.buttons..This.sets.the.LOW.END.calibration.point.
to.zero/zero..
2.. Set.the.20.mA.endpoint.as.described.above.under.
4-20.mA.calibration.
3.. The.special.0-20.mode.will.remain.in.effect.until.a.new
. 4.mA.endpoint.is.established.in.the.usual.way..
Auxiliary 0-5 VDC
The.4-20.mA.Transmitter.is.equipped.with.an.auxiliary.
voltage.output.with.a.range.of.0-5.VDC..This.signal.is.
capable.of.dropping.to.within.a.few.milliVolts.of.zero,.
and.thus.may.be.more.suitable.for.use.in.the.0-20.mode.
No.special.equipment.is.required.to.use.the.0-5.V.out-
put,.but.wiring.to.customer.equipment.is.different.(see.
Wiring.Diagram.4).
Changing Response Time
The.4-20.mA.Transmitter.comes.from.the.factory.with.a.
default.0.7.second.response.time..This.should.provide.
good.performance.with.all.GPI.G2.meters..
WARNING
If you reset the response time (procedure detailed
below) you MUST then reset the 4-20 mA endpoints.
To.give.good.performance.with.a.variety.of.sensor.types,.
many. frequency-to-analog. converters,. including. the.
GPI.4-20.mA.Transmitter,.offer.two.or.more.settings.for.
"response.time".(sometimes.referred.to.as."setting.time,.
or."averaging.time").
.
•. Longer.(slower).response.times.are.needed.for.sen-
sor.types.that.generate.very.low.frequency.outputs.
(like.oval.gear.flowmeters).
.
•. Shorter. (faster). response. times. are. preferable. for.
sensors.that.generate.higher.frequency.outputs.(GPI.
meters,.for.example)..
.
•. Longer.(slower).response.times.are.also.appropriate.
in.situations.where.sensor-output.frequency.fluctu-
ates.or.wobbles.substantially.
.
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