Hooking Up a PLC And Bench Power Supply - Page 1
Forum section: electronics / beginners

author: eev_carl
author_rank: Regular Contributor
timestamp: March 09, 2020, 03:42:08 pm
content: Hi,I'd like to hook up a Click PLC to my Rigol DP 832 power supply. I was planning on using solid core 22 gauge wire, running wires from +, -, and GND to the corresponding three terminals on the PLC. I read that the wire is good for 0.91 A. Am I reading the PLC datasheet correctly in that its current draw will than this (500mA)? I don't have any external modules and expect the inputs and outputs to involve low current. This is all the help me learn ladder logic so it's not headed to any specific environment.The datasheet specification I'm referring to is the Power Supply Specification section in this PDF.https://cdn.automationdirect.com/static/manuals/c0userm/ch2.pdfIs there anything I might be missing or should I purchase Click's power supply?Thanks,Carl

author: GerryR
author_rank: Frequent Contributor
timestamp: March 09, 2020, 05:27:52 pm
content: It looks like there are two supplies available, one providing 24 VDC at .5 A and one providing 24 VDC at 1.3 A. So, if you are not using much in the way of I/O, the 24 VDC at .5A should be fine. You do not need their power supply; yours will be fine.

author: Gregg
author_rank: Super Contributor
timestamp: March 09, 2020, 05:38:17 pm
content: The amperage rating for the wire is dependent on the length of the wire and how well it can dissipate heat. All wire has resistance.The total amperage needed is listed in the instruction manual under “power budget” page 2-24; just add the requirements for all the modules etc. The Rigol DP832 is certainly capable for powering everything you may want to add and if the power cable gets warm, you can always run two sets of wire in parallel. Are you are just bench testing the PLC? If so, short runs of 22ga wire should be OK. The PLC should function within a reasonable range of voltages as PLCs are built for industrial applications where conditions are often less than ideal.If you need a dedicated power supply, Meanwell may be just as god or better than the Click and much cheaper.

author: Jwillis
author_rank: Super Contributor
timestamp: March 09, 2020, 05:44:04 pm
content: The current consumption varies from 120mA to 160mA at 24VDC for each PLC module type . Which specific module do you have . The power supplies they have are designed to supply more than one PLC and/or other peripherals.The PLC will only use as much current as it requires so having more available current is not a problem.

author: eev_carl
author_rank: Regular Contributor
timestamp: March 09, 2020, 07:18:25 pm
content: Quote from: Gregg on March 09, 2020, 05:38:17 pmYes. I'm doing this so that I can learn ladder logic and wire some NPN and PNP sensors. My course is on Allen Bradley equipment so anything more "real world" can be done there.

author: eev_carl
author_rank: Regular Contributor
timestamp: March 09, 2020, 07:19:47 pm
content: Quote from: Jwillis on March 09, 2020, 05:44:04 pmThe specific click controller is C0-10DD1E-D. I think i can get by with what's on the unit without any extra I/O or other modules.

author: floobydust
author_rank: Super Contributor
timestamp: March 09, 2020, 07:45:58 pm
content: Note the PLC requires an earth gound connection, on the 4-pin DC power connector.This is so it does not float and pick up common-mode noise from field I/O or the power supply.It can upset analog modules and RS-485 etc if the PLC is not earth-grounded. I would connect to the Rigol green binding post.

author: eev_carl
author_rank: Regular Contributor
timestamp: March 09, 2020, 07:52:06 pm
content: Yes. Thanks for explaining that. I'm planning on taking 3 22 AWG wires and connecting +, -, and GND to the corresponding screw terminals underneath the PLC unit.

author: eev_carl
author_rank: Regular Contributor
timestamp: March 12, 2020, 02:12:38 am
content: Thanks everyone. I'm up and running. This CLICK is pretty cool with free software. Hooking up a PNP capacitive sensor and an inductive NPN one

author: floobydust
author_rank: Super Contributor
timestamp: March 12, 2020, 03:26:24 am
content: I have used big name commercial PLC's and they rip you off with the licence keys for the programming S/W you can spend over $5,000 a year just for that, on top of overpriced I/O modules. Then it's another $5,000 for the HMI software and key. I look forward to when these big dinosaur companies stop gouging people just because their PLC controls expensive equipment.This PLC looks low cost and there is also anopen-source Arduino-compatible PLCthat looks interesting, not expensive.You might scream in agony doing Ladder Logic, it's antique from an era of relay logic. It can't really do complicated controls without jumping through hoops. Even a latching relay for a motor start/stop can be many coils and a couple rungs, although some vendors have flip-flop modules. I prefer a programming language instead. Sometimes you need a Case/Switch statement or a way to convert bytes.The highest stress I had is stopping/starting the PLC in a plant environment. I wasn't sure what state the outputs would go to, and leaving a valve or pump etc. open/off or a process in a wrong state could lead to disaster.