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schematic

simulate this circuit – Schematic created using CircuitLab

Previously my project had two Hitachi camera(http://www.hitachi-kokusai.co.jp/global/en/products/tv/download/gige/pdf/KP-F_D_XXGV_OperationManual_E.pdf).

I had connected triggering pin 8 and 9 of camera using following circuit.Both the cameras were connected in parallel and power supply was DC 12V.

Both the cameras were getting triggering in this circuit. Now when I have added additional 2 cameras so in total 4 cameras(parallel connection) none are getting triggered.

Suggestion please. Doing it for first time so even if I missed some basic stuff pardon me.

mosfet used was (http://www.irf.com/product-info/datasheets/data/irlz34n.pdf)

Thank you!

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  • \$\begingroup\$ Can you capture the signals and compare if they reach a valid logic levels? Long wiring inductance may cause problems from high impedance. So ensure using twisted pairs. There needs to be a pullup R for a positive pulse . Where is it? \$\endgroup\$ – Sunnyskyguy EE75 Oct 11 '17 at 22:34
  • \$\begingroup\$ There is no GND in your circuit and no GND path from your FPGA. You are also triggering with a 1 V power source. Page 57 of the manual says you need 5 V. \$\endgroup\$ – Transistor Oct 11 '17 at 22:35
  • \$\begingroup\$ @Transistor I think he draw the sketch in a hurry... \$\endgroup\$ – Sean87 Oct 11 '17 at 22:57
  • \$\begingroup\$ Sean87 you are right :D @Transistor FPGA Gnd and circuit gnd are same and also power source is 12 V \$\endgroup\$ – S K Oct 12 '17 at 0:39
  • \$\begingroup\$ Are you going to fix your question? You will waste the time of other people if you don't. \$\endgroup\$ – Transistor Oct 12 '17 at 8:42
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enter image description here

Figure 1. Page 57 of the user manual you linked to shows that the input is opto-isolated internally. Trigger voltage is 5 V.

The internal opto-isolator means that we don't have to worry about ground referencing the two circuits and creating any kind of ground loop will not be a problem.

schematic

simulate this circuit – Schematic created using CircuitLab

Figure 2. Switching circuit.

It seems to me that you have reverse polarity on your trigger pins. Try Figure 2a and b.

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  • \$\begingroup\$ Yes I did labeling mistake in my schematic my circuit is like your Fig 2b but with 10.2 ohms additionally between mosfet source n ground node . This was circuit was working when two cameras were connected. But now when I am trying to trigger 4 then are not getting trigger. When I disconnect the additional two cameras connected it get trigger . \$\endgroup\$ – S K Oct 12 '17 at 1:16
  • \$\begingroup\$ What voltage do you get on 8 if you hold the control signal high? You are now trying to pass 12 mA through it (which shouldn't be a problem). \$\endgroup\$ – Transistor Oct 12 '17 at 16:39
  • \$\begingroup\$ pin 9 voltage with reference to pin 8 I am getting 11.8 voltage after control signal is kept high. \$\endgroup\$ – S K Oct 12 '17 at 16:55
  • \$\begingroup\$ Then your FET isn't turning on adequately. It should be close to 0 V. Check your FET specs to see what gate voltage is required to turn it on fully. \$\endgroup\$ – Transistor Oct 12 '17 at 18:05
  • \$\begingroup\$ pin 8 is close to 0 only when triggered is set high and pin 9 is approx 11.8 V. Also I checked the specs of mosfet vgs is good to turn it on completely. This circuit is triggering two cameras but as soon as I connect third camera or more entire circuit won't trigger any of cameras. \$\endgroup\$ – S K Oct 13 '17 at 0:21

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