JUMO TYA S202, Руководство по эксплуатации

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V1.00/EN/00709725 [Thyristor power controller TYA S202] 67
6 Special device functions
6.1 Detection of load faults
The load monitoring function detects the percentage change in resistance of
the load. It can detect and signal a load failure, partial load failure, or a partial
load short circuit.
Undercutting
current This function is used for one or more heating elements connected in parallel
that are to be monitored for failure.
Overcurrent This function is used for several heating elements connected in series that are
to be monitored for short circuits.
Function This function not only takes the decreasing or increasing load current into con-
sideration but also includes the load voltage in the monitoring process.
The plant's correct load ratios are saved during Teach-In.
Based on this state, the load changes are continuously monitored irrespective
of the required output level. In the event of a failure or short circuit of a heating
element, the load current increases or decreases. This is detected by the load
monitor and a load fault is signaled.
Limit value A limit value must be entered as a % in the configuration or operating level for
load monitoring. This limit value depends upon the number of heating ele-
ments connected in parallel or in series.
For heating elements with a high positive or negative temperature coefficient,
a suitable limit value must be determined independently. The values in % giv-
en below (see arrow) are used for this purpose.
A value in % is displayed for each of the three phases, which represents the
current deviation from the Teach-In values as a percentage. Access this win-
dow via Operating level
r
Monitoring
r
Limit value load monit.
H
These values can be used to find out in what phase a load error occurred. If a
load break occurs in phase L3, for example, the value in % exceeds the set
limit value (10 % in the table).