Parameter description
The following values can change the equipment characteristics
and are therefore to be set with utmost care.
A1: Switch mode contact K1
A2: Switch mode contact K2
The switch mode for the relays, i.e. cooling or heating function, can be programmed independently
at works. Heating function means that the contact opens as soon as the setpoint is reached, thus
power interruption. At cooling function the contact closes, if the actual value is above the required
setpoint.
A3: Function of contact K1 at sensor error
A3: Function of contact K2 at sensor error
In case of open-circuit or short-circuit at sensor 1 the display indicates a flashing “F1”, at sensor 2
a flashing “F2”. At sensor error the selected relay falls back into the condition pre-set here.
A5: Selection setpoint 2 or DeltaW
This parameter determines whether the setpoints for thermostat 1 and 2 independently adjustable
(A5=0) or whether they are tied with one another via a switching offset DeltaW (A5=1). This
parameter applies only to contact K2 (see parameter P1).
A6: Control characteristics contact K1
A7: Control characteristics contact K2
Independent choice of either PID or thermostatic characteristics for each contact. If contact K2 is
set as PID-contact, it operates with setpoint 1.
A8: Display mode
The value can be indicated in integrals or with decimals. In general, all parameter indications are
presented with decimals.
A10: Indication value for lower value linear analogue input
A11: Indication value for upper value linear analogue input
Only relevant, if the controller is programmed for a voltage input (0…10V linear) or a current input
(4…20mA linear). These parameters allow scaling of the linear analogue input. The value to be
indicated for the lower and upper entrance value then defines the range the controller will indicate.
For input range 4…20mA the display will show sensor error if the input signal drops below 4mA.
A19 Parameter lock
This parameter enables locking of each parameter level. If third level is locked, only parameter A19
may be changed.
A20: Minimum action time contact K1 ”Off”
A21: Minimum action time contact K2 ”Off”
These parameters permit a delay in switching off the relay in order to reduce the switching
frequency. The adjusted time sets the entire minimum time period for a switching-off phase. If PID
characteristics are selected the minimum action times are set to zero.
A22: Delay after “Power-on”
This parameter allows a switching-on delay of relays after switching-on the mains voltage. This
delay corresponds with the time set here. The delay is only active when the controller is switched
on the first time. The delay applies not to the alarm contact.
Summary of Contents for ST48-WHDVM.04
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