Certified TestStand Developer Sample Exam Issues

[Michael_Howard]

I downloaded the CTD sample exam from the Certified TestStand Developer Badge page. While creating a sequence to execute the test specification, I noticed the SP25 library does not function properly; the Read Status function from the SP25 library does not changes states when the Power Supply Voltage is set to a voltage level greater than 12V. I verified this behavior by creating a VI in LabVIEW to execute the test specification and the results were identical. 

[ShockHouse]

Have you waited the necessary time after applying the power? According to the user story it says, "After receiving power, it takes the SP25 3+ seconds to become operational."

Another place I might look is whether you are configuring the power supply correctly. It needs the Current Limit set, the Voltage set, and the Output set.

[Michael_Howard · Accepted solution]

I was able to resolve the issue. The Apendix section for the SP25 API has a typo for the Initialize.vi "Name" parameter value. The document states the "Name must be COM2"; it should state, the "Name must be SP25". Also, after setting the DC Power Supply voltage, the the output of the DC Power Supply must be set to the ON state; this instruction is not included in the Test Specification for Test 1, Test 2 or Test 3. Lastly, the DMM Analog Read VI's (Voltage and Current) do not work; the Digital Read VI's can be used to make the analog measurements (very confusing). After I struggled with the documentation for several days, I believe the Solar Panel Charger Test Specification document and the VI documentation for the support VI's need some improvements. I hope the CTD exam does not have the same issues. If so, many people will struggle to pass the exam if the same issues are present.

I have attached an update version of the specification for those who may be interested.

[ShockHouse]

I'm curious what led you to want to use the Analog lines instead of the Digital lines? Reading through the documentation it says "There are 9 active lines on the DMM. All of them are digital lines."

How could that area of the documentation be improved to emphasize that better?

[CertifiNATEtion]

Thanks for catching this!

I've updated the prep material download with a corrected version of the user story document. 

Nate

[Michael_Howard]

A digital signal is defined as signal that has two states on or off. These levels typically are 5V or lower. The instructions require the developer to measure the output of the battery; which is considered an analog signal because the level can be anywhere from 0V to the expected maximum voltage. When configuring a DMM to measure Voltage and/or Current, there are two things to consider, current flow (AC or DC) and signal range. With that said, I tried making the measurements using the Digital Voltage Reading VI's but had no success; which was due to the API typo. So, I tried the Get Analog Voltage\Current VI's. 

As for documentation clarity, I made changes to the document which I believe will make it easier to understand.

Best Regards,