19
Using theOffsetFeature
This featuremakes itpossible tocontrolmore thanoneactuatorwithout increasing the
numberof BCDor serial input lines. Theactuator’sSOvaluecanbe set from“1”to“96”,
minus thecurrentNPvalue (thenumberofpositions theactuator is set to index). Once
anSOvalue is set, that value is thefirst (or lowest)positionanactuatorwill recognize.
The factorySO setting is“1”,soanactuatorwithanNPvalueof 10 responds tomove
commands forpositions“1”to“10”. If theSOvalue is changed to“10”, theactuatorwill
respondonly tomovecommands forpositions“10”through“19”. For any settingof SO
andNP, the lowest validpositionwill be theSOvalueand thehighest validpositionwill
be theSOvalueplus theNPvalueminus1;
i.e.,
theactuatorwill respond tocommands for
positionSO throughposition {SO+NP - 1}.
Theexamplesbelowdescribea system thatwill step sequentially from1 through31
witha single instruction. However,note thatwhenpositionsare selected ina random
sequence,position16must alwaysbe requestedbeforeanypositionshigher than16are
selected.
Figure12
helps illustrate this: sincebothactuators respond toacommand
togo toposition16,stream16will flow throughvalve1/port 1,out thecommonport
of valve2, intovalve1/port 16,andoutof thecommonportof valve1. Thereafter,any
stream select command that isabove16willmoveonlyvalve2;whenamovecommand
for aposition less than16 isgiven,valve1willmoveandcutoff all flow fromvalve2.
WithBCDControl
Here ishow this canbe featurecanbeused to setupa31-stream stream selection system
using sixdedicatedBCD linesand two16-positionvalvesandactuators. Refer to“Using
theManual Remote toConfigure theActuator”onpage3as required.
1. Use themanual remote toenable theauto-latching featureonbothactuators. This
eliminates theneed for adata latch signal.
2. Use themanual remote toassign the
secondactuator anoffset valueof “16”,
giving it avalidposition rangeof 16 to
31.
3. Useapieceof tubing toconnectport
16of thefirst valve (on theactuator still
carrying the factory-defaultoffset valve
of“1”) to thecommonportof thevalve
on the secondactuator (whichnowhas
anoffset valueof “16”).
4. Connect streams1 through15 to
ports1 through15on thefirst valve,
and streams16 through31 toports1
through15on the secondvalve.
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Figure12:
Using theOffset feature
