ya...The DAQ supply is separate from other supply..AH...i just notice...i always didnt connect the Vgnd to the DAQ (-)..May b that the reason i cant control the output Voltage..But also i try put a 1K sine wave to the audio input, the output didnt show any sine wave..where might have the sine wave gone to? i try to check every pin but other than pin 6..i cant find any sine wave..is it possible that 1k sine wave got filter away?

 

ya...The DAQ supply is separate from other supply..AH...i just notice...i always didnt connect the Vgnd to the DAQ (-)..May b that the reason i cant control the output Voltage..
Without that VGnd to DAQ Common/0V connection you would not have any control over the voltage on pin #11

But also i try put a 1K sine wave to the audio input, the output didnt show any sine wave..where might have the sine wave gone to?
What is the voltage measured between the VGnd and pin #11 of the SSM.??
This will set the Gain,, tell me what you measure with the DVM

i try to check every pin but other than pin 6..i cant find any sine wave..is it possible that 1k sine wave got filter away?
If the pin #11 voltage to VGnd is incorrect you will have a problem

When you inject the 1KHz signal into pin #6, do you have 1uF and 18K components connected as the datasheet shows.??

Also where is the 0V/common of the 1KHZ signal source connected to on the SSM.??

 

i measure the voltage at VGnd and pin #11 and its show 7.5v...

Yup..i did the same as shown..the Audio gnd was connect to the same gnd as the OP284..and the gnd of the Function gen also go to the same gnd..

 

i measure the voltage at VGnd and pin #11 and its show 7.5v...

Yup..i did the same as shown..the Audio gnd was connect to the same gnd as the OP284..and the gnd of the Function gen also go to the same gnd..

You should use VGnd for the Function generator 0V, not the OP284 0V.

You should not have 7.5V between pin #11 and VGnd, you have a grounding problem,

Post a fully marked up image on how you have the FuncGen, SSM and the DAQ and any other units connected on the project, showing how its all interconnected.

 

So i shd be doing this...

1) check my DAQ Voltage
2) remember to gnd my DAQ
3) Change FuncGen's ground to Vgnd
4) lastly check my circuit again
Will try it again when i go to school later..Thank..

 

hi,
You have not shown on your circuit, the DAQ power supply connections.??

If the 0V/Common of the +15V power supply to the OP284 +/-7.5v source is connected to Ground and the DAQ and/or FG power supply common is also connected to the same Ground, you will still have the problem.

The 15V PSU that supplies the OP284 MUST be 'floating' ie: isolated from Ground. You should check that it is isolated, use a DVM on Resistance measurement.

You should be aware that your SSM may have been damaged due to your earlier incorrect power supply connections..!
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