ISPSoft User Manual During the program writing, the software automatically provides suitable variable symbols which have been created for option. Use the up 「↑」 and down 「↓」 keys of the keyboard or simply select the desired one from the list by pressing the left button of the mouse. A function block is created by selecting the C language option for the Language field as below. The editing of a C function block is the same as that of a C program. Type or modify the expression following the C syntax format in the following Edit workspace through your keyboard. 16-6