SIMATIC S7-200/300/400, Step7, PCS7, CFC, SFC, PDM, PLCSIM,
SCL, Graph, SPS-VISU S5/S7, IBHsoftec, LOGO ...
- Posts: 1
- Joined: Wed Aug 09, 2017 1:38 am
I have a project used PCS7V8.2 & IL & 315-2DP,
and I create a FB like "Lag" in APL.
The SCL program is shown as follows：
Code: Select all
OUT := SEL(G:=LAG_T<=0.0,IN0:=IN + (sr_lv_out-IN)*(EXP(-Sample_T/LAG_T)),IN1:=IN);
sr_lv_out := OUT;
If the input ("IN") is fixed in a negative number always , and a few hours later,the output("OUT") shows “NaN”.
Is floating-point calculation overflow ？
- Posts: 7
- Joined: Wed Apr 21, 2010 6:24 pm
Show whole FB (with interface)
- Posts: 2
- Joined: Mon Aug 23, 2010 6:32 pm
"NaN" means "Not a Number".
To find the error we need to see the whole block !
- Posts: 29
- Joined: Wed Mar 27, 2013 2:37 pm
Check your formula. It seems that the output of your function divides on 0 or the output is infinit or out of range of your variable.