Help with FlexMod P3 fault LED

Hi Guys,

New guy here having some problems with my FlexMod P3. My setup is the following:

- 12V input into a controller
- 12V input into FlexMod from controller
- 3.3V TTL signal from controller
- no ground wire for TTL signal since power and TTL are from the same source
- beam standby suppression is installed
- interlock not installed
- 50mW laser diode 405nm

So the problem that I get is that the Fault LED light is on when my TTL signal is low, when it goes to 3.3V the fault turns off and my laser is turned on. I cannot adjust the Bias since I don't have any output when the TTL signal is low. I think that this is also causing problems with the pulsing because when looking at the output vs the TTL signal input, the output only dips slightly when TTL goes low so essentially the laser is constantly on it seems because the intensity does not change when TTL on vs off duration is adjusted.

From the manual: With standby beam suppresion, the interlock and open loop sensing functions are not available.

Does anyone have any ideas or tips? Any help will be greatly appreciated.

Thanks
Sebastian