Loop troubleshooting effort -- success!

Each student, in nearly every lab activity, must troubleshoot a fault the instructor places into a measurement or control loop. They are given 5 minutes to isolate the type and general location of the fault, and more time (if necessary) to precisely identify and rectify it. The instructor begins by playing the part of a bewildered operator, telling the student (the technician) what the system isn't doing right. Throughout the exercise, the instructor asks the student to explains their reasoning and their diagnostic method to ensure they aren't just guessing theuir way through.
In this activity, the student's troubleshooting procedure was good, and he was able to identify both the nature and location of the problem within 5 minutes using simple test equipment (a multimeter and a wire jumper).

[@Skill.Issue.808]

Wish I had teachers like this that actually did things like this.

[@BTCInstrumentation]

The transmitter has a pair of "test" terminals connected in parallel with a diode carrying the 4-20 mA signal. Connecting an ammeter in parallel with this diode causes the diode to turn off, with 100% of the loop current going through the meter. In any other circumstance it would be wrong to connect an ammeter in parallel to measure current, but here it works!

[@ebade3000]

This is an excellent introduction to what students are expected of when going through your program and also working in the field. Students should really be encouraged to watch this to see if this way of thinking is interesting to them. Thanks again tony.

[@andrewkendall1634]

Excellent tip shorting the thermocouple to show ambient temp

[@JugurthaHadjar]

This is awesome. I love the questions. I recently exposed some college projects in front of three teachers. I was just delighted one of them was asking the very questions I asked myself when I designed the project. I worried about the thermal lag between the fluid reaching a certain temperature, and the sensor actually measuring it, but I calculated that it wasn't too bad. He asked me about it ! To simplify the code, I chose a °C calibrated sensor and he asked me about it too. Smart teacher.

[@catertrader11]

just came across your site, your doing a great job with content and delivery, very easy to follow need you in the TAFE system in Australia

[@TheMightyHellfish]

"Did anybody come out here and mess with this?" "If they did, they wouldn't admit it..." - that's Instrument tech gold... along with "The reading was stuck so I 'tapped' it..." :)

[@piercewentworth8043]

Heard that a few times! Ha!

[@CM-oy2kd]

That’s a good student who has been listening. I bet he’s a senior tech now

[@christianmarquez3143]

Thank you for your videos.

[@Metallizombie]

Nice video. I found the shorting tip to be very useful. I don't think I would've though of that one.

[@siyabonga6156]

If he had measured the milli amps in series he would have quickly diagnose the fault , he would have gotten 0 mA that is a good indication for open circuit, but he chose to measure it in parallel due to the 250 ohms resistor in the smart transmitter.

[@malikgarrett2036]

great video

[@rodrigomorado2426]

Good tips thank you

[@rhythmandacoustics]

Why did he get higher than 20mA reading when it was open? Shouldn't the meter have showed 0 mA which means open and no current/signal because minimum was 4 mA?

[@kieranhimself9124]

na failed high, could be how the transmitter is set

[@genoporter7863]

The transducer will output high current while reading high resistance.

[@Nanzyen]

According to requirements of their plant, they calibrated the transmitter to a FAIL SAFE HIGH, which means when there isn't a signal from the thermocouple, the transmitter would then give off a HIGH signal. More than 20mA.

[@rhythmandacoustics]

@@genoporter7863 open circuit = 0 amps

[@rhythmandacoustics]

@@Nanzyen this answer makes sense. Thanks.

[@metalz88]

thank you for this video .

[@thybigballs]

Where is this type of training conducted? Any alternate suggestions? I'm sorry if you mentioned it in the video, but I can't hear anything. Thanks

[@kevin5843]

great video.

[@yanashimanskaya1872]

Ok, why did he use jumper wire? Isn't there gonna be 0 volts between terminals when they are shorted? I don't understand how it works.

[@MD-cd7em]

GOOD DEAL...THANKYOU

[@garyverth4887]

I'd be checking mV straight away

[@BTCInstrumentation]

The sound is perfect when I try playing the video -- not sure why you're not getting any sound. This is filmed in the Instrumentation lab at Bellingham Technical College, in Bellingham, Washington, USA.

[@NoobThreat]

Hello sir, are you still teaching at BTC?

[@actarisful]

is that right measu amp with paralel wire?

[@bablukhan64]

ty....for the video

[@hamsaljroh7]

sound is not that clear thank you

[@ElectricBuckeye]

That's okay, but there are better ways to go about troubleshooting it, in terms of steps, than just going immediately to the MM and reading back.

[@abrammedrano4392]

I was check the connections 1st. Then proceed from there

[@greywolf271]

Fuck, troubleshooting basic instrumentation must be the most boring job in the world. Thank christ I studied electronics

[@kieranhimself9124]

fuck that connect fluke proccess meter to TC compare the measurment. 2 second job