RedLion Crimson 3.0 (Float) Data Tag error Value

[M0Dark]

Hi,

I have a complex database in Crimson 3.0 and in one of the display pages I am trying to get a tag to show the sum of several other tags. The Tag in question here is a Float Number Tag.

7 of them are integer values sent from a modular controller, which means there is never an issue with what Crimson is seeing and it is always an integer value. I can add all of these together, multiply them by 1.0 and Crimson is happy to display the Float Value that I want to see.

My problem comes then after that I need to add a single value to this total. The source for this is a Modbus device which is addressed at Device(7).302009.Real. This device may or may not be connected and that is giving me a problem. While the device is connected I am getting a total, but with the device switched off I get a greyed out ----.

I have a flag tag which defines if this device is active or not.
I have tried to set the totalizer to use an if statement based on whether this is active or not Shortened Version down below.

Int F1:=FX1+FX2+FX3+FX4+FX5+FX6+FX7;
Float F2:=F1*1.0;
Float F3:=0;
If (FCor_Meter_Select==1)
F3:=FCor_Value;
Return F2+F3;

This doesn't work at all and the value is --- when the FCor_Meter_Select is not 1.
I have troubleshooted this as best I can and as soon as FCor_Value is null it throws the null to the return regardless of what FCor_Meter_Select is set to.
Is there a better way to do this that will not give me an error, or can I somehow set the FCor_Value tag to read 0 on error not ---?

Many thanks for your help.

 

[kolyur]

Crimson will always attempt to read all of the tags referenced in a program. It will choke when it can't access a value, even if that tag isn't needed based on the program's logic. One thing to try: In the Properties screen for your program, try turning on the "Run Anyway" checkbox.

 

[BryanG]

There may be a work around. I guess that you are directly connecting a Tag to a Modbus value, instead add a gateway block to the Modbus device, and then transfer that to a Tag. In a test I did here with no Modbus device connected, it just treated the missing Modbus value as zero. In the manual it is under Using Communications / Adding Gateway Blocks.

 

[M0Dark]

Got it to work by putting a program in (just: If (FCor_Meter_Select==1) NewTag:=FCor_value else NewTag:=0), as you said with the run anyway checkbox ticked. Then used the Tag from that in all the other tags etc.
Thanks.