ECKELMANN VS 3015 CT, Инструкция по эксплуатации, Страница: 63 / 219

Firmware V1.41 V1 08.11.2022 63/219
Any further switching is only performed if a specific time for the flow or return has elapsed and the control error
has exceeded a specified value (neutral zone).
The time depends on the actual control error. In the case of larger control error, the switching is performed after
a shorter time than for smaller control errors. The switching time is calculated from the sum of a basic time t
b
and a variable time t
v
. A distinction is made between stepping up and stepping down of the step controller.
The variable time is inversely proportional to the control error. In the case of maximum control error, the variable
time t
v
approaches zero. In the case of declining control error, the time t
v
is automatically increased up to the
specified maximum time.
If the positive control error (actual value > setpoint) is greater than 1.5 times the neutral zone, the fan is
switched on after the configured switching delay that must not be longer than 30 seconds. The fan is activated if
a delay of more than 30 seconds results from the basic time and variable switch-on time.
While the control error is greater than 1.5 times the neutral zone, the maximum switch-on delay remains limited
to 30 seconds. If the control error is smaller than 1.5 times the neutral zone due to the starting up of the fans,
any switch-on is not performed until after expiry of the configured switch-on delay again.
The basic time and the maximum variable time for the switching forward (switching on) and back (switching off)
are parameters that can be configured for every switching forward/back of a gas cooler capacity stage. The
following apply for determination of the switching times:
The following applies for t
v
:
The following applies for d
t
> d
t_max
d
t
= d
t_max
t
v
= variable switching time
t
v_max
= max. switching time (configurable for each stage)
d
t
= control error
d
t_max
= max. control error (configurable)
The switching time is calculated for every controller cycle. In each case, the variable time is recalculated and
the elapsed time since the last switching point is compared with the calculated time. If the calculated switching
time is less than or equal to the elapsed time, fan activation is performed if the control error is greater than the
specified neutral zone.
The following diagram shows the switching time calculation: