How to use the Piecewise command in Sigma Graphics.

[Product_Support]

Issue

When displaying a multi-value status from a programmable object in Sigma Graphics, updates may not reflect correctly unless the object value changes significantly (e.g., from 0 to 100). This can cause display issues when the graphic is open and the state changes.

Product Line

Satchwell BAS & Sigma

Environment

Sigma Graphics Ver 4.0 onwards

Cause

Sigma Graphics does not automatically update the display unless the programmable object’s value changes in a way that triggers a refresh. This is problematic when using objects that return multiple discrete states.

Resolution

Use the Piecewise command with stacked text objects to display the correct state visually.

Step-by-Step Workaround

1. Create a Programmable Object
   Example logic:

   10 IF POINT 0|123 = 1.00000 THEN RETURN TRUE "Off"
   20 IF POINT 0|123 = 2.00000 THEN RETURN TRUE "Text No1"
   30 IF POINT 0|123 = 3.00000 THEN RETURN TRUE "Text No2"
   40 IF POINT 0|123 < 1.0 OR POINT 0|123 > 3.0 THEN RETURN "Invalid"
   

2. Design the Graphic

   • Create three text objects:
     • 1 – Off
     • 2 – Text No1
     • 3 – Text No2
   • Stack them vertically with "Off" at the bottom.
   • Align them precisely over each other to form a single visual stack.

3. Combine and Configure

   • Select all three text objects and combine them into one.
   • Assign a Piecewise command to the combined object:
     • Object: 123
     • Min: 1
     • Max: 3

4. Behavior

   • The graphic will display the appropriate text based on the object’s value.
   • If the value is 0 or greater than 3, the display will be blank.

---

Notes

• This method works best with analog values from programmable objects.
• Variations are possible depending on the number of states and desired display behavior.