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PGA309: PGA309EVM Multi-cal

Part Number: PGA309

Luis,

In the interest of moving forward I realized the system verifies communication and configures the attached PGA309's before proceeding to the calibration steps. I connected my PGA309 PCB's to the Multi-cal system to verify this function on all channels. I noted that channel "4" had a communication error. While diagnosing it. The same error popped up on channel "8" during the diagnosis of the channel "4" comm error.  When I restarted the program Channel "8" started working. Then after some more time diagnosing channel "4" the communication error popped up on channel "6". All my devices were verified with the USB DAQ platform individually before I started using them with the Multi Cal system and I know they work fine after a number of calibration cycles. Also, I changed out the PGA309 pcb on channel 4 to one that worked in another channel just to be sure, still the same error. I probed both the "Pos" and "Vout' lines at the breakout board. The failure is the power isn't coming on to the channels that register a communication error. I probed the "On-to-vout Ctrl" test points on the Mux board and found that the ones that were working were cycling to 5v and the channels with comm errors were not. My 5v Vdut supply has plenty of current handling and is not drooping. I'm not sure what would cause a random problem like this nor do I understand why logic outputs would just stop and start working (Thats at least in the case of channels "6" and "8". Channel 4 has not powered up so far.) When the "On-to-vout Ctrl" test points signals are there, they rise quick and to full logic levels no sagging or slow rise times. When they don't, they just remain at ground. 

Again any help is appreciated!

Joe

  • Hello Joe,

    In the past, I have experienced intermittent issues when one of the Multi-Cal-Interface cable is broken or when the DSUB connectors are not screwed in correctly.  Can you please confirm, are the screws in the DSUB connectors fully tightened and properly seated?

    However, since you are seeing intermittent issues on different sites, site 8 and site 6, perhaps something else is amiss.

    - Can you provide the full schematic of your PGA309 Custom card schematic?

    - Is the Custom PGA309 module configured on voltage output 3-wire, voltage output 4-wire or current output mode? 

    - Please include a diagram of the connections between the PGA309 custom card to the Multi-Cal-Interface PCA Card connections on the setup.

    Also, kindly update to the latest PGA309 Multi-Cal executable below (although, the software update is not related to the intermittent issue above)

     https://txn.box.com/s/ar3gt7kdwhw1njno10uch6vkwnzz6523

    Thank you and Regards,

    Luis 

  • Luis,

    Thanks for your response to my problem. I will get the requested information to you tomorrow. I have verified the cables are functional and properly seated. I want to point out however that the signal to activate the channel power is not happening. The "On-to-vout Ctrl" test points on the MUX board are not going positive (5v) on the affected channels therefore the channel power is not activated at all. In any event I will work on the list of things you recommend first and get back to you.

    Thanks again,

    Joe

  • HI Joe,

    Thank you, let me know when you would like me to review the schematic, I assume you are testing three-wire voltage modules.

    I am not certain what would cause the intermittent issue.  One particular circuit that "could" be of interest is the "One-wire Speed-Up Circuit", on the USB DAQ Platform controller, discussed on the USB DAQ Platform User's Guide on page 11.  JUMP8 on the USB-DAQ controller needs to be connected 2-3 to activate the one-wire speed up circuit, and allows the UART interface to be connected to lines with high capacitance, the circuit is used to speed up the rising edge of the UART signal.

    Default Jumper configuration for USB-DAQ:

    Thank you and Regards,

    Luis

  • This forum request was resolved/addressed via direct conversation off the forum