dsc module question

[andheri]

hi,

 i am using labview7.0 with DSC module. iI have connected two instruments on bus . Each instrument is having  25 tags. In .scf file i have already loaded these 50 tags . Now i want to read these tags to get its values. I am getting proper values in tag value array. But  when my vi is running and my both instruments are in communication i am getting zero value in status array in between if i power off my instrument (i.e. communication fail) some elements of status array becomes -653600 or 0 or any random value.  I need some specific values in status array when instruments are in power off condition and my vi is running condition. So that usig status array i can display message as instrument is in power off condition.

so do the needful

[CharlieM]

andheri,

I understand you post above as:

1) When both instruments are powered on and working correctly you receive correct values in an array.

2) When you power down an instrument, unusual values appear in a status array.

3) You ultimately want to interoperate the values of the status array to indicate the condition of the instruments.

I would need to know the following:

1) Can you view the status array and value array in a server viewer or another client?

2) Do the arrays match what you see in LabVIEW?

3) What do you expect to see for status when the instrument powers down.

4) What do you expect to see for status when the instrument is working properly?

Knowing the answers to the above questions will help determine the best options for coding in LabVIEW.

Message Edited by Charlie M. on 10-12-2007 10:25 AM

[unclebump]

Try using Tools, DSC Module, Monitor Tags to see whether the status is good for all of the tags. We really need a bit more information about how the devices are connected to the computer. You mention a bus, is it serial RS232, RS485, ethernet??? What protocol do the devices use?? Are the tags all of the same datatype?? Do you want to read all of the values all of the time?? Or only some of the tags after certain conditions are met??

I like to assign the tags to groups, then use some DSC vi's to read all of the tags available in a group. Sort them into ascending order, then pass them into a Read Multiple Tags vi.

What are these devices?? If they are test instruments, you may not need the DSC module.

Message Edited by unclebump on 10-12-2007 07:04 PM

[andheri]

dear sir thanks a lot

i am using instruments which are connected on rs 232 bus. Now my application is that i want to read the tags from these instruments and the value of all tags i want to display in front pannel of my program. Here some tags value of floating point and some of them are interger type and i want to read all these tags at a time. whenever i am reading these tags i am getting proper value of tags. In between if i shut down my instrument this value array remains same as previous. So in front pannel of my program the instruments are showing the same tag value even they are in power off condition.So to show the power off condition i want to use that status array so that i can display the power off condition in front pannel eventhough my software is continously in running condition.

please suggest me any other option to show this power off condition.

falgandha Mohire  

[CharlieM]

Can you be a little more specific on what is in the status array, how it functions, where it comes from?

[andheri]

DEAR SIR

this status array will get when i read all the tags using read tags function and status array is the output of read tags function.

thanks a lot

falgandha

[CharlieM]

Falgandha,

If your server is not seeing any changes when the instrument powers down than DSC, or any other client, will not either. I was just wondering what kind of tag data you had available that you could attempted to code a trigger from. It sounds like the status data you are receiving isn’t particularly useful. I suppose you may need to come up with some creative solution based on what you have available to you.

[andheri]

thanks a lot

OPC server is giving the changes for some tags value when instruments come down to power off condition and not giving for some tags even though all tags are of same data type i.e. analog data type

falgandha.