Jump to content

Timer Preset Behavior

Recommended Posts

  • MVP 2023

I wonder if someone from Unitronics, or some other knowledgeable person could provide a detailed explanation of how Timer Presets behave. With Timers, there is an extra option besides just "Power Up" value being set or not set. I can enter a Timer Preset in Visilogic without checking the box for the "Power Up" value and that Preset gets transmitted to the PLC during program load. If I subsequently change that Preset, either in Visilogic or in the PLC, then there will be a dialog box requiring me to harmonize them if I do another program download. However, if I load the same program via the SD card I get different behavior. It appears to me that the Timer Preset in the program on the SD card (either .v57 or .c57 file) is ignored when downloaded. I would think, especially when I'm downloading a Clone program, that the resulting PLC would be identical to the PLC that uploaded the file. This is not the case with respect to Timer Presets.

What is the behavior I should expect? And is it any different if I have checked the "Power Up" box in the programming?

Link to comment
Share on other sites

  • MVP 2023

Here is what my testing reveals:

1) It makes no difference whatsoever if the "Power Up" box is checked for Timer Presets. If the Timer Preset is changed from its original value a Reset does not change the Preset and an Initialize returns the Preset to the original value whether the box is checked or not.

2) If the application is downloaded to the SD card, a subsequent upload to the PLC has no effect on Timer Presets no matter whether the Presets were changed or not. Whatever value was in the PLC at the time of the upload remains in the PLC. In other words, if the Timer Presets were messed up, whether inadvertently or otherwise, THEY CANNOT BE FIXED BY AN APPLICATION UPLOAD OR EVEN A CLONE UPLOAD! This caused me some embarrassment at a customer site last week. I expected a Clone to mean a Clone, not Clone everything EXCEPT Timer Presets.

3) If the Operands are downloaded to the SD card, then an Operand Upload WILL CHANGE THE TIMER PRESETS.

Is this information helpful to anyone? Is this the behavior I should have expected?

Link to comment
Share on other sites


It is definitely helpful. I myself am not a fan of how visilogic handles retentative values and especially that of timers. I would much rather see the "initial values" method completely abandoned in favor of the "current values".

When I want to make abosolute certain I am cloning the operand values I use the "Remote Access" utility and uload all those values into a csv file. I also do not reference timers directly but instead buffer all presets using MI operands. This circumvents some of the flakey behavior you note above.

  • Upvote 1
Link to comment
Share on other sites

Hi Flex727,

Please - if you want to get answer from "someone in Unitronics", the best way is to send the question to "someone in Unitronics" - to support@unitgronics.com. We are making our best to give high level professional answers within 24 hours.

A post in Forum is oriented to large sociaty of users and we give especially chance to other users to participate and give their opinion. If thhere is a need - post with answer we don't hully agree with or no answer for several days, we participate.

About Timers:

Power Up check box with timers is to state, that on power up the curent value of the timer will be reset.

The Preset value in the Timer box is loaded with Download to Flash memory of the controller. When one change the timer preset value, the new valye is stored in RAM. While Download again, VisiLogic checks if there is difference between values in RAM and in FLASH and asks how to synchronize. As I know, this option will be optimized in the new VisiLogic version to give the programmer option to select synchronizing way for each timer, where there is a difference.

About clonning - please let me check your claim and I'll post the results later.

Link to comment
Share on other sites

  • MVP 2023

Thank you. I posted here with the assumption that the information would be of general interest. I definitely appreciate your customer support and it's certainly a major reason that I prefer to use and recommend Unitronics whenever I can.

Regarding the Timer Power Up check box, you say: "Power Up check box with timers is to state, that on power up the curent value of the timer will be reset", BUT THAT IS NOT WHAT HAPPENS! Whether the box is checked or not, the Timer Preset does not revert to the Power Up value on power cycle or manual RESET.

When uploading a program from a laptop vlp file, the Visilogic software will always require the timer presets to be synchronized and will not proceed without changing the preset values in either the laptop or the PLC. However, when uploading a program from an SD card, the upload completely ignores the timer preset, whether from an application (v57 file) or from a clone (c57 file), AND WILL NOT CHANGE THE VALUE IN THE PLC.

I consider both of these situations to be flaws.

By the way, if it's important, I am using Windows 7 - 64bit, Visilogic 9.4.0, and a Vision 570 OPLC.

Link to comment
Share on other sites

  • 3 years later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...