Hello,
One of my detail face plates (we can call it AI_EA_NOL.grf) show the Trip Hi Lim as 5, but the Trip Hi Lim is configured for 4.5 in the control module.
I notice Datalink Custom Page for the text field in DeltaV Operate Configure the text format for this field is set to Alpha-Numeric.
The Trip Lo Lim text format is showing correctly and its field is set to Numeric.
I am thinking I should change to Numeric.
I am just wondering why its showing 5 instead of 4.5.
Thanks for any help or comments.
What is actually configured for the datalink?
DVSYS.@MOD@/AI1/HI_LIM.A_CVDECPT[OUT_SCALE]
?
According to the 'Special Scaling Field Types' article in Operate's DeltaV Display Parameter help file, this is:
"Used to read a parameter as text while applying the number of decimal places specified by the scale parameter. Writes to this parameter must be done in Engineering Units."
In this case the parameter for number of digits after the decimal for the AI1/OUT_SCALE range parameter will dictate the formatting of the number. It is probably default to zero at this point.
If you change to numeric, you may lose all formatting and get 4.49999, or something like that.
In reply to Youssef.El-Bahtimy:
Thank you Yousseff.El-Bahtimy for replying.
Where can I find the help file you mentioned? Books Online?
I am not by the DeltaV now, but I return in the morning and I will post you the what is configured for the datalink. This is an interesting problem!
Thank you
Hello
The configured datalink is DVSYS.@MOD@/ALM1/HI_HI_LIM.F_CVDECPT[IN_SCALE]
In reply to DCS Newbie:
In the expression builder dialog in Operate, then click 'Help on Display Parameters', then select 'Special Scaling Field Typres', you'll see the reference for how to use CVDECPT.
In your case, if you look at the control module ALM1/IN_SCALE 'Decimal Places', what do you see? Is it 0?
Thank you Youssef,
I see 2 decimals places.
Also, when I notice my expression is built with DVSYS.@MOD@/ALM1/HI_HI_LIM.F_CVDECPT[IN_SCALE] but the special scaling field types only show to use CVDECPT with the ".A" (.A_CVDECPT)
Should I change my expressioin to include .A_CVDECPT instead of .F_CVDECPT?
THanks
I just tested your scenario and the problem is the F_ prefix. When the A_ prefix is used, the behavior is that the number is formatted per the decimal points specified in the range parameter within the [ brackets ].
If you change the datalink to numeric and specify the whole digits and decimal, these values will apply for ALL modules that use the detail display, which should not be universal based on the type of process variable.
I would recommend sticking with the standard (in the AALM.dt standard detail display) and use
DVSYS.@MOD@/ALM1/HI_HI_LIM.A_CVDECPT[IN_SCALE]
instead of
DVSYS.@MOD@/ALM1/HI_HI_LIM.F_CVDECPT[IN_SCALE]
Change all the other ALM1 limit datalinks in your detail accordingly (lo lim, lo lo lim, etc.)
I will make the update and let you know if it works.