Cscape Programming May 2026

// Open file (append mode) h_file := FileOpen(filename, 'a'); IF h_file > 0 THEN FileWrite(h_file, ADR(csv_string), LEN(csv_string)); FileClose(h_file); Write_To_Log := TRUE; ELSE Write_To_Log := FALSE; END_IF Create a ladder rung for user control:

1: // Bump test - apply step change Output_Value := Output_Value + PID_Tune_Bump_Size; IF Output_Value > 100.0 THEN Output_Value := 100.0; END_IF // Wait for process to settle (5 seconds) IF Timer1.Q THEN PID_Tune_Step := 2; Timer1.IN := FALSE; ELSE Timer1.PT := T#5s; Timer1.IN := TRUE; END_IF 2: // Calculate PID parameters using Ziegler-Nichols PID_Tune_Response_Time := Measure_Response_Time(Process_Value); PID_Tune_Ultimate_Gain := 4.0 * PID_Tune_Bump_Size / (3.14159 * PID_Tune_Response_Time); // Calculate gains PID_Tune_Kp := 0.6 * PID_Tune_Ultimate_Gain; PID_Tune_Ki := 2.0 * PID_Tune_Kp / PID_Tune_Response_Time; PID_Tune_Kd := PID_Tune_Kp * PID_Tune_Response_Time / 8.0; PID_Tune_Step := 0; PID_Tune_Enable := FALSE; Log_Enable := FALSE; END_CASE cscape programming

// Timer for sample interval IF Log_Enable AND Timer2.Q THEN Write_To_Log(Log_File_Name, Log_Index, Process_Value, Output_Value); Log_Index := Log_Index + 1; Timer2.IN := TRUE; // retrigger ELSE Timer2.PT := REAL_TO_TIME(PID_Tune_Sample_Time * 1000); Timer2.IN := Log_Enable; END_IF FUNCTION Write_To_Log : BOOL VAR_INPUT filename : STRING; index : DINT; pv : REAL; out_val : REAL; END_VAR VAR line_str : STRING(80); csv_string : STRING(80); h_file : DINT; END_VAR // Open file (append mode) h_file := FileOpen(filename,