rupeje

Thanks Flex!

Hello all, I tried searching but couldn't find this exact question. Is there a preferred cable to connect a laptop USB port to the RJ11 port on a V120? This is for program changes only. This is more of a quick favor so would rather purchase the correct cable than build a custom one. I have a USB/RS232 serial adapter (DB9) already if that's half the battle. Thanks so much!

After about a 6 month period of not having any VisiLogic projects, I've dove back into it in full force. I just downloaded the latest version, v9.8.64, but when I go to download the projects, no text will display. I even created a brand new project and downloaded it to a fresh Samba, and still get everything but the text. I remember having this issue with one particular older version a few years ago, but never was able to resolve it except to use an older version. Does anyone else have this issue with text on SM43s using v9.8.64?

I understand what you're saying, that it doesn't calculate anything for you. However, to "set" a PID's output when transferring from manual to auto, you have to preload the integral error. The proportional error is already calculated upon transfer to auto and cannot be changed since it is simply a calculation based on the setpoint minus actual. The integral error is a compounding output, and must be preloaded to where it would need to be to make the automatic PID output equal to the manual output it was previously at. So it absolutely CAN be done, but we would need to know what the value in the "force integral error" refers to?

Is there any way to run a trend in the background, so when you first "open" the trend, it is already populated with the historical data? What I'm seeing is that I can "open" a trend, but it only starts logging when it is opened. If you close it to do something else, the history is lost.

I know there is a way to do it, as many other PLC manufacturers have this function enabled automatically when transferring from manual to auto. I have a general understanding of the math involved- but no understanding of what the value in the "Force integral error" block means?

But does "Burn upload project" also encompass the "Download all and burn", or just allow it to be uploaded?

Does "burn upload project" encompass everything that "Download all and burn" does, in addition to allow the project to be uploaded? Just curious because I've never been sure, and I usually end up doing both just to be safe, but that can take a long time, as we all know. Thanks!

I hate to resurrect this old thread, but I'm having this same issue with bumpless transfer from automatic PID to manual. I see that you can input a value into the "Force integral error" functon block, but there are no instructions on how to back-calculate the required integral value. I've tried putting in constants for the forced value, but the results are random and unpredictable. I suspect there is a calculation required. Has anybody ever figured this out? Thanks!

Thanks for the help! I've written some code for zero crossing, I'll give it a test when I get a chance.

Has anyone had any luck implementing a deadband for their PIDs? I don't see a built-in option for that, and I'm wondering how to go about it. Can you do it by disabling the PID net when the process variable is within the deadband (after zero-crossing or other scheme), and then re-enable the net when the process variable goes outside of the deadband, or would that cause issues with the integral calculation?