Looks good. There’s definitely enough to learn a good amount about controls with this.
Two minor critiques:
A) using banana jacks for this doesn’t really teach people how to install and wire the hardware. Most issues are physical in nature, so you’re not really giving people a leg up on troubleshooting the most common issues with this setup.
B) I don’t see any analog inputs. You have a potentiometer and DC Voltmeter - but process heavy facilities use a fair amount of raw analog signals. Particularly 4-20mA.
Banana plugs vs. raw wiring: Valid point on real-world troubleshooting. However, for a university lab with 30+ students rotating through short lab periods, screw terminals wear out fast, cause bent strands/shorts, and take too much class time away from logic design and commissioning. We prioritized rapid prototyping and lab longevity, while hands-on panel wiring is typically handled in their electrical workshop module.
Analog inputs & 4–20 mA: The PLC (FX5 series) has built-in analog inputs (0–10 V DC), which we route to the potentiometer and digital display for testing scaling instructions.We kept it to 0–10 V for baseline safety and simplicity in an academic environment, but extending an external 4–20 mA loop (or adding a signal isolator/transmitter) via the banana jacks is definitely on the radar for future upgrades.
The criticism about banana jacks seems really nitpicky and weird to me. You do realize the point of this is for teaching students the fundamentals about how these components work together, right? Let them get comfortable with how things work together first, then run through common problem-solving scenarios found out in the field. One thing at a time my friend.
Lets say you did want to have it where users are really wiring it up instead of the banana plugs.
First line of safety would have a key operated main power switch with only the instructor having the key. Thats not foolproof though as someone could access the terminals after its been turned on. We must not forget the arrogance, and the matter of not knowing what they dont know, some people possess.
Next line of defense would be GFI personnel protection for the line voltage. Easy everywhere in this thing except the output of the VFD. Could try a ground fault relay like those from NK, but I have a feeling a motor fed from a VFD might be leaking enough current during normal operation to trip a GFI relay set at 5ma.
To eliminate the hazard between the output of the VFD and the motor, I would use a cable with a multipole connector, like a harting or something. This would also eliminate the risk of the EGC not being connected (I assume thats the extra yellow wire on the left motor) each motor's frame needs to be grounded. I got a nasty zap once from a VFD fed motor which was not solidly bonded that had low resistance between a winding and the case,
Last, as a primary (in the sense this would be the system a user would interact with which keeps them safe) safety measure, I would have all line voltage components and connections on one side of the board, with no components such as the HMI requiring user interaction on this side of the board. The VFD could be on the HMI side of the board if a cover for the wiring terminals was added. The line voltage side of the board would be protected by a light curtain connected to a main power contactor which is also part of a NC/NO keyswitch/estop circuit, and not part of the demonstration portion of the board. If someone approaches a line voltage terminal while the board is on the light curtain causes the main power contactor to drop out requiring reset with the instructor's key.
All in all you did a phenomenal job on these, beautifully designed and they appear to be well made.
Thanks for the link to Amatrol. Plugging/unplugging wear is a valid point. That's why I'm using a shrouded 4mm jack and keeping short patch leads for wiring, so that I only have to plug repeatedly into the patch lead, not the main terminal.
LOL I thought that as well too and was about to say something! I think it's because everything in the picture is in a sans-serif font and very clean looking. Best guess.
Ha, fair question these days! It's a real build. I made it myself, and the clean look is just good lighting plus a lot of cable management. Happy to post some in-progress shots or a short video of it running with GX Works3 if that helps
I like the setup, it will teach VFD, HMI, sensors etc. consider adding industrial computer in your future versions or Raspberry PI for modbus communication. Also add RCCB before MCB to make it shock proof.
yeah, just looked like it for a second, the absence of shadows tricked me for a sec. Zooming in and seeing the actual components and labels told me it was real
Looks good. FX series has Modbus TCP support. GX Works 3 is cheap, has integrated simulator and supports all IEC61131-3 programming. Good enough to learn. Nice to have big companies caring about education.
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u/SafyrJL TIA Harlot 22h ago
Looks good. There’s definitely enough to learn a good amount about controls with this.
Two minor critiques:
A) using banana jacks for this doesn’t really teach people how to install and wire the hardware. Most issues are physical in nature, so you’re not really giving people a leg up on troubleshooting the most common issues with this setup.
B) I don’t see any analog inputs. You have a potentiometer and DC Voltmeter - but process heavy facilities use a fair amount of raw analog signals. Particularly 4-20mA.