Emerson Exchange 365

• Not Answered

AO(4-20ma) CHARM testing problem , RT_WRITE_ACCESS_DENIED

Hello 

Hope this one finds you well 

I am student in a process automation program and I am working with DeltaV s-series in my final year project, i am trying to test the AO(4-20 ma) of the CHARMS, the charm is added successfully and it gives a solid green LED which to my understanding means that it should work fine. I am connecting the AO to a control valve that accepts (4-20 ma) signal. 

I added a AO function block from the IO tab in the  control studio window and i saved the module and assigned it to the controller, however when i try to use the debug mode to change the output( i am basically trying to test the AO by changing the OUT valvue)  it would give me an error message , i have attached a picture of the error message below. 

I just don't know what to do , i am trying to test the output and then use that later in my programming logic.

I don't know if i need specific parameters in order to change it , any suggestion will be greatly helpful

Your help is greatly appreciate it.

Thanks 

Zahraa

• AO CHARM TESTING CONTROL STUDIO

ZahraaK

• 9 Oct 2014 2:28 AM
• Cancel

1 Reply

• Steven Estes

  

  • 13 Oct 2014 7:45 PM

  A few things to check:
  
  1) Make sure that you are logged in to DeltaV when attempting this (I know this is simple but is the first easy thing to check)
  
  2) Check the properties for the workstation that you are on by right clicking it in the control network in Explorer and selecting "Properties." See the check box for "Restrict on-line changes to areas assigned to the Alarms and Events subsystem of this station." If this is checked and the area where your module resides is not assigned to the alarms and events of your workstation then you will get this error. You can either uncheck this box or assign the area of the module you are testing to the alarms and events of the workstation. If you are just using this system for testing then there should be no reason for this to be checked.
  
  3) Are you using a DeltaV administrator account? If so then it cant be a parameter security issue as administrators get all DeltaV keys by default. It sounds like you are just using a class test system and should have an administrator account. If not, then make sure that the account you are using has the "Control" key assigned to it either for the area you are putting your modules in or as "sitewide." The control key is the default lock for the "OUT" parameter. You can check this in User Manager (DeltaV-> Engineering-> User Manager; or from the icon in DeltaV Explorer). Double click on the account you are using in User manager to bring up the properties window. Go to the "Keys" tab and verify whether you have been granted the "control" key. If not then grant this key and download the changed set-up data and log out and back in to DeltaV (a prompt will appear letting you know this).
  
  Also note that the AO block must be in manual mode in order to write to the OUT parameter so be sure to throw it into manual mode when doing this.

  • Cancel