1.6 PROGRESSIVE HEATING OF BOILER ELEMENTS
Specifications:
To avoid over-consumption on boiler start-up, the heating elements are heated progressively, and stopped progressively when the boiler is stopped.
This operating principle is shown by the following timing diagram:
An “On” (MA) button authorizes the activation of the first heating element (S1). After a time-delay T, the second element (S2) starts up. After the same time-delay, the third elements starts up (S3), then the fourth element (S4) again after time-delay T. An “Off” (AR) button deactivates S1. The three other elements are progressively deactivated after time-delay T with each deactivation of the preceding element.
Description of the inputs/ouputs:
Model Required:
No specific condition:
SR2 B121 BD (24 V DC) or SR2 B121 JD (12 V DC) for example.
Program Description:
In principle, time delay T is identical for the activation/deactivation of all the heating elements. The program includes three TIMER function blocks. The function to perform according to the specifications requires entering the same time-delay value in the three blocks.
As a result, if the user wants to modify one of them, he/she will have to enter the new selection in the three blocks.