Resistance Limitation (R-Control) - JUMO 709061/8-01-032 Operating Manual

6 Special device functions

6.6 Resistance limitation (r-control)

H
Function
Limitation of the
power
90
.
This is only possible in power controllers with current and voltage
measurement that are fitted with subordinate control P (Code 001
in the order code) and only functions for load resistors with a posi-
tive temperature coefficient.
In three-phase economy circuits, no direct resistance limitation is
possible because the individual resistance value is not recorded.
However, the limiting function itself can be applied.
It operates both in burst-firing operation and phase-angle operation.
If the current measured value for resistance exceeds the resistance limit, it is
limited by phase-angle control or limitation of the switched sine waves.
The resistance limitation parameter can be used to activate limitation of the
power output depending on the resistance value R when operating molybde-
num disilicide heating elements in order to prevent overheating of the heating
element in the upper temperature range. By measuring the resistance of the
heating elements it is possible to assign a precise heating element tempera-
ture.
If the load resistance exceeds this value, it is limited by phase-angle control or
limitation of the switched sine waves.
This protects the heating element from overheating.
V1.04/EN/00561071 [Thyristor Power Switch TYA 201]]