@@hlukanirikhotso1597 (associate) Software Engineer. I work on code ranging from data acquisition on real-time OSs to tools and software to run on desktop PCs. Sometimes it’s GUIs and code for controlling hardware and other times it’s command line tools running in “the cloud.” If you include my hobbies/future work, that would extend down to bare metal microcontrollers and up to web design. The content on this channel does sometimes give me tips that I can apply to my own work, and some of the content gives me insight to the systems my code may interact with. Really though, I’m mostly here just because I find the topics very interesting and @RealPars presents them well.
That means a lot, Usher! Thanks for sharing that with us. If you have any questions while watching our video courses, please feel free to contact us at any time! Thanks again and happy learning!
Hi Abdullah, Thanks for your comment and topic suggestion! I will happily go ahead and pass this on to our course developers. In the meantime, the following video course might be helpful as well czcams.com/video/nY0LaLxusho/video.html
04:50, what if the PLC logic is too complex to simulate? Isn’t much better for I/O testing force the output signal and see if the relay or contact activates?
It is always better to engage the actual hardware components in any simulation or system logic checks. Most often, this is not possible since the hardware and I/O may be in the process of being installed in the field at the time testing is required. A good simulation, regardless of the complexity of the software and logic, should be designed to tie "outputs back to inputs" and allow for direct input of analog values. Full dynamic simulations are usually possible as well but take longer to plan and set up. You need to decide what level of simulation/program checkout is appropriate for your needs. Typically, it will take 5%-10% of the time taken to create your program logic to create a "tie-back" simulation; 10% - 20% for a full dynamic simulation. Your simulation and testing strategy should be part of your Functional Specification document and needs to be planned for up front. When I program PLCs, my control module logic (device control logic) and equipment module logic (equipment functional logic) have simulation code built right into the logic. When I need to simulate the system at the "tie-back" level, I simply need to set the simulation bit. If I need to do a full dynamic simulation, I add a program block or file to do all of the necessary calculations and setting of analog values. Don't forget the power of your HMI interface in setting conditions and monitoring the logic!
@@realpars Many thanks for the feedback, as you explain seems to be having a simulation program block might help in the long run. I will try it next time. cheers!
Great channel. I've followed you on LinkedIn immediately. but about the test, I have faced another issue the names in the circuit diagram (the names of components in the factory) were different from the site and that made a problem by wasting the time to understand the right wiring type.
Part of commissioning is to match the actual device in the field with what is shown on the wiring diagram. If I have a digital input or digital output card, most devices with one of two types (contact closure or 3-wire solid-state). I have had the same thing happen over the years, but with a little practice, you will be able to quickly match the field instrument to how it should be wired to the PLC. As a side note, I would also ask the engineering company who designed the system to explain the discrepancy between the field device and what is on the wiring diagram. There may be bigger issues (working off of old drawing revisions, missed updates, mislabeled devices, etc.).
Yes, digital inputs can be simulated by jumpering the appropriate voltage from a power supply to the input terminal of the PLC. This is electrically what would exist if the input device were energized. This can be dangerous if you are not experienced in doing this. 24VDC circuits from different power supplies should not be mixed. Always use power from the same power supply circuit as would normally be used by the device. Analog inputs can be simulated with a Fluke process meter or other devices that can generate 4-20 ma for loop-powered devices. For Profibus PA sensors, there is a simulation mode that allows testing of the analog signal to the PLC. Digital outputs and analog outputs should be forced from the PLC to simulate.
@@realpars Thanks for your prompt and such detailed explanation. Thanks for sparing your valuable time. Really appreciate your excellent work. Keep it up...
I would only add the information that it is easier to just force the digital outputs in your PLC one by one. Its straightforward and easy process, and you don't have to go inside the program logic and check the trigger conditions.
For DO why not just use Watch Table Force Mode for it? The DOs inclusion conditions in program may be anaccessble at all, for example they can include time delays, some inner flags or variables.
Yes, you could certainly use this method for testing DO points. Many times, if the logic is simple or repetitive, such as with valves, it may be better to test the logic as well as the outputs at the same time. The method of testing is up to the engineer performing the test.
Technically, you can't. Triggering an output on a PLC output card has to be done via logic or via a "force", both of which require a connection to the PLC. You can load a "bare-bones" hardware configuration with no program elements and force the outputs.
Dear Engineer , you are awesome and explained very simple...God bless u
That's great, Khalid! Thanks for your support.
This channel is tailored for me and my career needs.
If you can make videos for failures inspection and maintenance plans.
It will be awesome
Hi Bushra,
Thanks for the topic suggestion, I will definitely go ahead and forward this to our creator team. Happy learning!
I like your videos even when they’re not directly applicable to my work. Great quality coming from this channel 💯
Thanks for your support, we're glad to hear that!
what do you do for work? I am curious.
@@hlukanirikhotso1597 (associate) Software Engineer.
I work on code ranging from data acquisition on real-time OSs to tools and software to run on desktop PCs. Sometimes it’s GUIs and code for controlling hardware and other times it’s command line tools running in “the cloud.” If you include my hobbies/future work, that would extend down to bare metal microcontrollers and up to web design.
The content on this channel does sometimes give me tips that I can apply to my own work, and some of the content gives me insight to the systems my code may interact with.
Really though, I’m mostly here just because I find the topics very interesting and @RealPars presents them well.
I rarely comment on CZcams but your channel is really awesome. Please keep it up with these awesome contents!
That means a lot, Usher! Thanks for sharing that with us. If you have any questions while watching our video courses, please feel free to contact us at any time!
Thanks again and happy learning!
Ole fluke 753 is a game changer
More for how to use the simulator..thank you from phil.
I like your videos. We need more . Also we need video that explains wiring digital input and output step by step
Hi Abdullah,
Thanks for your comment and topic suggestion!
I will happily go ahead and pass this on to our course developers. In the meantime, the following video course might be helpful as well czcams.com/video/nY0LaLxusho/video.html
It's very usefull to new learner .thanks lot
Glad to hear that, Halesh!
You guys are the best of all
Thank you very much, Amos!
Vedio is knowledgeable
Great sir...
Well made! Good job!
Thanks a lot! Great to hear that, Fred
Very useful video 👌
Hai bro
Thank you!
Good job sir.👍👍
Thank you!
04:50, what if the PLC logic is too complex to simulate?
Isn’t much better for I/O testing force the output signal and see if the relay or contact activates?
It is always better to engage the actual hardware components in any simulation or system logic checks. Most often, this is not possible since the hardware and I/O may be in the process of being installed in the field at the time testing is required. A good simulation, regardless of the complexity of the software and logic, should be designed to tie "outputs back to inputs" and allow for direct input of analog values. Full dynamic simulations are usually possible as well but take longer to plan and set up. You need to decide what level of simulation/program checkout is appropriate for your needs. Typically, it will take 5%-10% of the time taken to create your program logic to create a "tie-back" simulation; 10% - 20% for a full dynamic simulation. Your simulation and testing strategy should be part of your Functional Specification document and needs to be planned for up front. When I program PLCs, my control module logic (device control logic) and equipment module logic (equipment functional logic) have simulation code built right into the logic. When I need to simulate the system at the "tie-back" level, I simply need to set the simulation bit. If I need to do a full dynamic simulation, I add a program block or file to do all of the necessary calculations and setting of analog values. Don't forget the power of your HMI interface in setting conditions and monitoring the logic!
@@realpars Many thanks for the feedback, as you explain seems to be having a simulation program block might help in the long run. I will try it next time. cheers!
Great channel. I've followed you on LinkedIn immediately. but about the test, I have faced another issue the names in the circuit diagram (the names of components in the factory) were different from the site and that made a problem by wasting the time to understand the right wiring type.
Part of commissioning is to match the actual device in the field with what is shown on the wiring diagram. If I have a digital input or digital output card, most devices with one of two types (contact closure or 3-wire solid-state). I have had the same thing happen over the years, but with a little practice, you will be able to quickly match the field instrument to how it should be wired to the PLC. As a side note, I would also ask the engineering company who designed the system to explain the discrepancy between the field device and what is on the wiring diagram. There may be bigger issues (working off of old drawing revisions, missed updates, mislabeled devices, etc.).
Excellent video. Can anyone tell please how to simulate the signal? Do you mean to jumper it?
I am trainee.
Thanks.
Yes, digital inputs can be simulated by jumpering the appropriate voltage from a power supply to the input terminal of the PLC. This is electrically what would exist if the input device were energized. This can be dangerous if you are not experienced in doing this. 24VDC circuits from different power supplies should not be mixed. Always use power from the same power supply circuit as would normally be used by the device.
Analog inputs can be simulated with a Fluke process meter or other devices that can generate 4-20 ma for loop-powered devices. For Profibus PA sensors, there is a simulation mode that allows testing of the analog signal to the PLC. Digital outputs and analog outputs should be forced from the PLC to simulate.
@@realpars Thanks for your prompt and such detailed explanation.
Thanks for sparing your valuable time.
Really appreciate your excellent work.
Keep it up...
I would only add the information that it is easier to just force the digital outputs in your PLC one by one. Its straightforward and easy process, and you don't have to go inside the program logic and check the trigger conditions.
Thank you for adding that! We very much appreciate that.
"Stay tuned" ... I will.
👍👍👍 video
90% of problems during initial testing are wiring issues.
The other 90% is component configuration...
👍🏻🇮🇳
For DO why not just use Watch Table Force Mode for it? The DOs inclusion conditions in program may be anaccessble at all, for example they can include time delays, some inner flags or variables.
Yes, you could certainly use this method for testing DO points. Many times, if the logic is simple or repetitive, such as with valves, it may be better to test the logic as well as the outputs at the same time. The method of testing is up to the engineer performing the test.
@@realpars Ah, got it.
This is what you call “Loop Checking”.
How can we test outputs if program not downloaded to PLC
Technically, you can't. Triggering an output on a PLC output card has to be done via logic or via a "force", both of which require a connection to the PLC. You can load a "bare-bones" hardware configuration with no program elements and force the outputs.