Hi,

I am developing a PLC with the need for some constants, when looking around the documentation I am unable to find how to do this so I have tried to use an analogue input setting the initial value to the desired constant. This will work but every time I build the program and run it the constant go to some random number. Is there any other method that I can use for this as it is not very practical to change the values manually before each test.

Regards
Dan

Hi Dan
Use an object of type Analog Value(Av) and set InitialValue in the development environment.

/Nylund

Thank you for the tip, I have tried changing from an Ai to Av but I am still getting two of the voltages changing in value each time when I run the program. I should also let you know that they are also changing to a specific value each time. Is there anyway in which I can stop this happening?

Dan

Hi Dan,

I assume you are running the 4..7.0-1 release in which there is an InitialValue bug. We will build a new release where this is fixed. Until then you can use pwrp_alias to set initial values. Create $pwrp_cnf/pwp_alias.dat and write lines like

mynode_setvalp H1-H2-MyAv. ActualValue = 25

where mynode is the current node. The file is copied to $pwrp_load when the node is built from where it's read at Proview startup. See Designer's Guide Navigating the project/Special files for more info. Note that you have to use setvalp not setval.

/Claes

Hi Claes,

Just a quick note on this, I have made the file in the correct location but still this does not work. My node is Processcontrol, and the plant heir is TempControl where the Av value 1VConst is so in the file I write:

Processcontrol_setvalp TempControl-1VConst.ActualVal = 1

This still does not set the value, and it keeps defaulting back to 0. Any pointers here? Is the structure right?

I have included a screenshot of my configurator if that helps.

Dan

Hi Dan,

You should write the network nodename, not the name of the nodeobject.

/Claes