twidosuite PLC

hi guys i am using twidosuite 2.20 plc programming. there is also a plc controller, TWDLMDA20DRT, in my system. the system controls the flow rate and also reads the time.

the question is, am i able to download any of these data into my laptop from the plc when the system is running, just by connecting my laptop to the plc? can i do downloading without HMI? or do i require external accessories to allow me to download these data?

thanks.

The question is, am I able to download any of these data into my laptop from the plc when the system is running, just by connecting my laptop to the plc?

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If you have the Twidosuite software, and the proper cable, and the proper communications port on your laptop, then you should be able to upload the running program to your laptop. For many PLCs, you can also do "online monitoring" and see the program data as it occurs.

Can I do downloading without HMI?

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Yes. A HMI operator panel is for controlling the PLC program, not for making changes to the program logic.

Or do I require external accessories to allow me to download these data?

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It always helps to have a sofware copy of the PLC user program (with comments, symbols, and instructions), and the PLC user password (if applicable).

thanks lancie.

so what you are saying is, with the PLC alone without the HMI, all a user can do is 'data monitoring' and no action can be done to either download or reset the running data?

No, that is not exactly what I meant. Theoretically, if you have the PLC programming software, normally you can upload "data" (contained in the PLC program) to a connected computer, and also make changes in variables, such as timers, counters, limits, setpoints, and so on. The PLC program is after all the center of process control, with the HMI operator panel serving as a control window into the PLC program.

But because these actions could be done using the PLC programming software does not mean that you should PLAN to use that method as a normal operating procedure. It would be very inefficient. It is normally much easier to make operating changes using the operator panel designed for that purpose - the Human Machine Interface, the "HMI" panel. The HMI can make any allowed change that has been programmed into the PLC program. If the data change procedure has not been programmed into the PLC program AND the HMI program, then you cannot do it using only the HMI.

To make major logic modifications, you still have to use the PLC programming software, not the HMI. But you should not assume that "with PLC alone" you will be able to access the PLC user program.

If you have the Twidosuite PLC software, and the proper cable, and the proper communications port on your laptop, then you should be able to upload the running program to your laptop.

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thanks lancie1.

i wish i can setup a HMI to view the running data, but unable to due to budget constraints. so to view the time and flow rate of the machine, i had to plug in the cable from my laptop to the PLC, and view the running data in twidosuite.

but can i change one of the VARIABLES to 0, or in other words reset it? variables meaning those %MF and %MW variables.

but can i change one of the VARIABLES to 0, or in other words reset it? variables meaning those %MF and %MW variables.

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Yes, you can BUT if the program is correct, operates successfully, then there will be some logic in its normal operation, where on the very next scan, miliseconds after your "reset", the PLC Central Processing Unit will find any PLC outputs that you have "reset" and put them back exactly where they "normally" should be when the program is in RUN mode and workkng correctly.

Now, in most major PLCs, there is a FORCE mode, so that when FORCE is enabled, you can FORCE PLC Inputs ON or OFF, and then the program will disregard the real input and act as if the input is as you FORCED it to be. Using FORCES to operate a PLC is not recommended for general use, can be dangersous, and should be avoided.

Hi guys I have a simple problem again but unfortunately I am not able to solve it.

The case is:
I have a water flow rate in my system, whenever the flow rate reaches 1000 litres, i would like the counter to hit 1 metre cube. Sounds simple right?
But then the problem is the flow rate is not a constant flowrate, so example when it hits 1013 litres, I manage to use counter to record 1 metre cube, but I convert the flow rate variable to 0, so the 13 litres is lost, which is inaccurate.

My PLC rungs are:
1) Flow rate hits >= 1000 litres - Give signal

2) Signal - Metre Cube Counter (with Reset button)

3) Flow rate + Timer (1s) - Flow rate back to 0


I know this is inaccurate, so any seniors have any suggestions?
Thanks.

There are two or more solutions.

(1) Don't use a counter for record the total Volume, but use a PLC memory location that allows for fractional numbers (numbers with a decimal point). Then each time your flow rate reaches 1000 or 1013, add 1 (or 1.013 to the old total volume.

(2) If you must use a counter, then you could use one for Cubic Meters, and a second counter for the Hundredths of Cubic Meters (Cu Metrers X 0.01).For each time that Flowrate >= 1000: Subtract Flow Rate - 1000 = Part Cubic Meters. Then Add 1 to Counter 1, and Add Part Cubic Meters to Counter 2. If or when Counter 2 = 1000, then add another 1 to Counter 1.