Queries using user defined fields

Question

Good day, 
 I am trying to established when the pressure in the system is more than the derated pressure rating. 
 The problem is that there is different pipes in the system (PN16, PN20, PN 25 etc.) and the derated values obviously differs for these pipes. 
 
 PN 16 = 133 m 
 PN 20 = 167 m 
 PN 25 = 208 m 
 
 (Based on 40 deg derating). 
 I set up a query as follows: 
 Pressure head > Derated pressure rating (see snip below) 
 
 Note: Juction_field_4 is a user defined field I created in user data extensions, named De-Rated Pressure (40deg) [m H2O] 
 
 However, when I use this query by right click/select in drawing method it selects nodes which pressure heads are below the derated pressure of that specific node. (see snip below) 
 
 Node J-2492 was selected, but the pressure head is 153 and the derated pressure is 208? This query did not work correctly. 
 
 Also when using a query with a specific value, i.e. Pressure head > 208, then it works. 
 But this is not ideal, because of different pipe sections with different derated pressure ratings. 
 
 Also, is it possible to use a query in colour coding? 
 
 Any assistance or comments will be appreciated. 
 
 Regards, 
 Jabus

Yashodhan Joshi · Answer

Hello, 
 I tried this with an example model and it worked for me. How are you storing the "De-Rated" pressure field? Since its a physical quantity, you should use the data type as "Real", Dimension = "Pressure", Storage Unit = "m H2O" and Numeric Formatter = "Pressure". Use the default values for different materials and create the user defined fields. 
 See this article for more details on User Data Extensions (UDX): How to create custom fields using User Data Extensions 
 If you are still unable to get the desired results we may need a copy of your model files for testing. See the below article on sharing model files over the forum; 
 Sharing Hydraulic Model Files on the OpenFlows | Hydraulics & Hydrology Forum 
 Let me know if this helps.

Jabus Venter · Answer

Hi Yashodhan, 
 Thanks for the feedback. 
 I used the "De-Rated" pressure field as described in your message above, but will have a look at the article and double check my method. 
 However, I found the following solution and thought I should post for future reference. 
 
 Created a user defined field (named: Pressure head > De-rated Pressure) with an iif function. (if pressure head > De-Rated Pressure, value if true = 1, value if false = 0). 
 I then colour coded the nodes to be blue when the value is 0 and red when the value is 1. 
 This way you can easily see what pipe sections are being over pressurised. 
 
 Hope this helps future readers.