Issues with sensors and external power
i've got rather large project i've been working on few months. i've been testing each component separately, , @ point i'm putting together. thing i'm (re)building 35mm motion picture film scanner 90s. able re-use of components (sensors, stepper motors, sprocket drive, etc). of individual pieces work fine, when test them on own. however, i'm having issues after putting whole thing together.
my setup involves pcb arduino mega 2560 shield made. has 3 25-pin headers, connect external db25 connectors, in turn go breakout cables connect sensors , motors. again, these check out fine individually. 1 cable motor , relay control, , other cable sensors.
all of sensors (proximity sensors , photo switches) require between 5 , 24vdc external power, , re-used 12vdc power supply in scanner. in testing, used benchtop power supply, i've tested power supply , works fine. should more powerful enough handle dozen or sensors needs power.
the issue i'm having this: when connect of sensors cable, , connect external 12v power sensors, work fine. each of them powers on, , each reacts accordingly when sensor tripped.
however, when plug db25 connector arduino, none of them power on , power lights on 12vdc power supply go out. when disconnect arduino sensor cable, power sensors , power lights on power supply come on. so, amiss.
the cable bundle consists of 5 shielded cables, common db25 connector. of cable shields spliced together, , ground arduino connects these. ground 12vdc power supply connects shields. in cases, there grounding wires built cables used (which tied chassis @ sensor). these spliced cable shield/arduino ground/power supply ground.
+12v goes 11 sensors single wire spliced quick-release connector outside cable bundle. i've checked none of ground/12v wires shorted inside cable. i've tested none of wires carry signals sensors arduino crossed, , none of them short circuited ground or +12v.
a bank of 12 pins on arduino (on pcb) have 4.7k pullup resistors, , use +5v out of arduino power. mirrors setup had on breadboard, worked fine. however, breadboard didn't more 4 sensors going @ once, , i'm wondering if resistors hanging off of 5v out on arduino causing problems.
any ideas?
thanks!
my setup involves pcb arduino mega 2560 shield made. has 3 25-pin headers, connect external db25 connectors, in turn go breakout cables connect sensors , motors. again, these check out fine individually. 1 cable motor , relay control, , other cable sensors.
all of sensors (proximity sensors , photo switches) require between 5 , 24vdc external power, , re-used 12vdc power supply in scanner. in testing, used benchtop power supply, i've tested power supply , works fine. should more powerful enough handle dozen or sensors needs power.
the issue i'm having this: when connect of sensors cable, , connect external 12v power sensors, work fine. each of them powers on, , each reacts accordingly when sensor tripped.
however, when plug db25 connector arduino, none of them power on , power lights on 12vdc power supply go out. when disconnect arduino sensor cable, power sensors , power lights on power supply come on. so, amiss.
the cable bundle consists of 5 shielded cables, common db25 connector. of cable shields spliced together, , ground arduino connects these. ground 12vdc power supply connects shields. in cases, there grounding wires built cables used (which tied chassis @ sensor). these spliced cable shield/arduino ground/power supply ground.
+12v goes 11 sensors single wire spliced quick-release connector outside cable bundle. i've checked none of ground/12v wires shorted inside cable. i've tested none of wires carry signals sensors arduino crossed, , none of them short circuited ground or +12v.
a bank of 12 pins on arduino (on pcb) have 4.7k pullup resistors, , use +5v out of arduino power. mirrors setup had on breadboard, worked fine. however, breadboard didn't more 4 sensors going @ once, , i'm wondering if resistors hanging off of 5v out on arduino causing problems.
any ideas?
thanks!
quote
and i'm wondering if resistors hanging off of 5v out on arduino causing problems.
have measured 5v? sagging.
what decoupling?
http://www.thebox.myzen.co.uk/tutorial/de-coupling.html
it time fault find measuring happens voltages rather saying not work.
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