Shananigans07 (Customer) asked a question.
I am in the process of sourcing materials to build a test stand that utilizes a pneumatic cylinder, a timer , counter, and start and stop buttons. The stand will be used by production, so I want to avoid using a PLC cause I do not want to be the gate keeper for the programming, additionally I would like to avoid the stand alone digital timer/counter. I have used them quite a bit in the past, I know how useful and powerful they are, but they can also be very complicated.
The test sequence is as follows.
- load part
- press start button > trigger timer relay and counter
- single action cylinder with spring return actuates on for 3 seconds
- cylinder returns and is at rest for 3 seconds
- cycle repeats 10 times
- test complete
The components I am confident I need are,
- Momentary on button to trigger cycle start
- timer relay with settings for on time and off time
- counter that can be used to set cycles and will end the test
- pneumatic relay
- power supply
- pressure regulator
- air cylinder
- miscellaneous fittings and tubing
I need help choosing the components that would work best for my application without overcomplicating it, and advice about components I may have over looked, or actually don't need. I am getting a bit of choice paralysis trying to figure this out on my own.
Thanks in advance
Despite your misgivings, I'd still go with the PLC and C-more HMI in your application. More flexibility in programming timers, counters, etc. in one package. Start/stop push buttons and totalizer numeric display on home page of HMI.
HMI: EA3-S3ML-R
Cable: DV-1000CBL
PLC: P1-M401-15DD2
PLC I/O connector: P2-RTB
Power supply (you'll need 2, one for the PLC, one for the I/O): PSA-24-75
The PLC and HMI can be easily coded to do what you're wanting to do. And it can expand to do things you've yet thought of having to do.
I am not understanding your reluctance to use a "stand alone timer/counter".
I am assuming your "pneumatic relay" should be a single solenoid, spring return, 3 way valve.
Pneumatic cylinder choices will be bore (related to force available), and stroke length.
Based on your constraints, you could do this with relay style timers. I would use one timer as a global on time, like a one shot set for 60 seconds or whatever it takes for 10 cycles of the cylinder. Then use a flip flop timer or multiple timers to make the cylinder extend and retract. Stop button stops the global timer or once it reaches it's limit, the global timer will shut itself off. Only issue I see is that I've never come across a counter that acts as a relay with a setpoint and output. They might exist, but someone else will have to chime in here. Usually they're the digital type multi function units which I believe you're trying to avoid? If you did this with just relays and such, you could avoid power supplies and just wire it all 110v most likely. I used to exclusively do simpler automation panels like this. Some older school companies didn't want to use plcs to keep their panels electrician friendly. Pretty much anyone could swap a realy or timer/troubleshoot some outputs with a meter.
The biggest issue I see here really is cost. You'll easily spend enough to just get a cheap standalone PLC (Click) which can do everything you need and more. You don't have to add an HMI if you want it bare bones. The programming would be very simple.
Agree this could be done with relays/timer/counter. The TRM-16-D-120AD for example could be set for cycle timer for the 3-sec ON, 3-sec OFF. To reduce inventory, the same timer could be used to time your 10-cycles. The 782-2C-120A for example, could be used to latch your system on when the start button is pressed. The same relay could be used to turn off your system when the timer times out, if needed. I like the dip switches on the timer, more deterministic and easier for someone to duplicate the settings, rather than timers with knobs. Rather than timing the 10-cycles, as you suggest, a counter could be used to count the cycles, the CTT-1C-A120 for example. The counter would be more deterministic than the timing. Developing a schematic, layout drawing, and BOM will assure you are ordering all the parts you need.
As mentioned, this could be done with 120VAC, no power supply, (unless your solenoid is not 120VAC).
As mentioned, a PLC has many advantages over relays/timer/counter. A PLC/ HMI does require programming with the laptop and software. But a relay panel is more expensive to make modifications to the logic by revising schematics and re-wiring relays. Adjustments to the timer listed above must be made with the door open. Adjustments to the counter listed above must be made with the door open and the controls energized. Many places will require special safety protocols to be used with this arrangement.