Hey everyone,  I'm new to Step 7 (v14) and PLCs in general.

I'm looking for a timer where an operator inputs the time value via an HMI (to a PLC Tag).  Then this value becomes the PT on the timer.  In working with the TON, how can I assign the variable (INT) to the PT?  Am I using the correct instruction?

Also, the timer seems to default to milliseconds. Will a calculation be needed to convert the value?

Many thanks.

You can convert from INT to TIME.

Whatever you want operators to enter needs to be expressed in miliseconds to be valid input a for timer.

Thanks for the response. 

Would it be a possible solution if the operator inputs the number of seconds into the HMI.  Then have a calculation (seconds entered) x 1000 convert to TIME data type move to variable used in the PT of the TON timer?

Thanks

Deane-ATI

Thanks for the response. 

Would it be a possible solution if the operator inputs the number of seconds into the HMI.  Then have a calculation (seconds entered) x 1000 convert to TIME data type move to variable used in the PT of the TON timer?

Thanks

 Hello,

 have a look below if the examples help you:

 https://support.industry.siemens.com/cs/ww/en/view/58667814

huggy_d1

If you want to limit operators from entering anything other than seconds, then set the HMI to accept seconds, and in the PLC, multiply whatever is entered by 1000 and store that to a tag that you then feed to the TON preset input. 

If the HMI is WinCC this can be done there. HMI->HMI Tags and find the tag. Then in its properties there's a tab "Linear scaling".

huggy_d1

If I recall correctly, you can use an INT on the preset input without converting to TIME datatype.  Try it.  Will save a conversion and making yet another tag to represent the same value.

It doesn't work. No matter if the IEC checks are on or not.

Ste39

 Hello,

 have a look below if the examples help you:

 https://support.industry.siemens.com/cs/ww/en/view/58667814

 

 This would be a wonderful help - I have the Starter kit that comes with S7 v14 SP1 Basic.  The example was written in v13 SP3 Pro.  So I can't see the PLC blocks or networks.

Any other examples available for the Basic version of S7?

jacek d

 

huggy_d1

If you want to limit operators from entering anything other than seconds, then set the HMI to accept seconds, and in the PLC, multiply whatever is entered by 1000 and store that to a tag that you then feed to the TON preset input. 

If the HMI is WinCC this can be done there. HMI->HMI Tags and find the tag. Then in its properties there's a tab "Linear scaling".

I'm using a  KTP700 Basic Color HMI panel.  The time value must be between 15 - 90 seconds.  Is it possible to filter the operator input so it is in the range?  Or another option might be to have a drop-down box of acceptable values in increments of 5 seconds. The operator would have 15 options.  Sounds like this can be done all in the HMI.   Any thoughts on the best approach?  D

huggy_d1

If I recall correctly, you can use an INT on the preset input without converting to TIME datatype.  Try it.  Will save a conversion and making yet another tag to represent the same value.

It doesn't work. No matter if the IEC checks are on or not.

So the conversion of the operator HMI input from INT to TIME seems to be the solution for the TON timer PT input, correct?   D

Having a while...

First of all - variable of type TIME can be aquired by HMI. Did you check the Visible in HMI and Accessible from HMI check boxes?

In HMI->HMI tags->Show all tags->your tag->Properties:

Linear scaling - here you can define so 1 (second) on the HMI means 1000 (ms) in the PLC

Range - here you can restrict what values are allowed.