53
ENG
µchiller +0300053EN rel. 2.2 - 14.12.2021
Functions
5.1.4 Request from BMS
The request can be managed directly from a BMS, bypassing normal temperature control and enabling the external request
signal (0-100.0%) via the specifi c Modbus serial variable (BMS_PwrReq, HR 331). This operation is enabled via another serial
variable (En_BMS_PwrReq, CS 22).
Note: if the supervisor is offl ine, the unit continues to operated in stand-alone mode, regardless of the request from the BMS.
5.1.5 High evaporator outlet temperature alarm
Chiller activates an alarm when the evaporator outlet temperature exceeds the threshold set by the user (via the off set relative
to the control set point). When the outlet temperature exceeds the threshold, a counter starts and after a delay (settable), the
alarm is activated. An initial delay disables the alarm in the transient period when the unit is starting.
Notes:
• the alarm is only available on chiller units.
• the high temperature alarm can be used to activate a backup unit in critical applications.
User Code Description Def Min Max UOM
U SetA Current set point - -999.9 999.9 °C
S U031 High water temperature alarm: off set 10.0 0.0 99.9 K
S U032 High water temperature alarm: delay at start-up 15 0 99 min
S U033 High water temperature alarm: delay in operation 180 0 999 s
300053_052_R01
t
t
Set point
AL
DT
D2 D2
D1
Key
Set point Current set point
DT Off set
D1 Delay at start-up
D2 Delay in steady operation
AL Alarm
Fig. 5.c
5.2 User pumps
Chiller can manage up to two user- side pumps (depending on the hardware used and the required confi guration).
A delay can be set between pump and compressor activation (= temperature control enabled). A delay can also be set between
the deactivation of the last compressor and the pump. If when the unit shuts down the compressors have been shutdown for
at least the “user pump shutdown delay after compressor”, then the pump is stopped immediately.
User Code Description Def Min Max UOM
S U047 Compressor activation delay after user pump 30 0 999 s
S U048 User pump shutdown delay after compressor 180 0 999 s
Tab. 5.d
300053_053_R01
D2
Note 1 Note 2
D2D1
On/Off
C
P
Key
Unit Unit On-Off (local or remote control)
C Compressor
P User pump
D1 Compressor activation delay after user pump
D2 User pump shutdown delay after compressor
Note 1 Control is not active: the compressors are stopped based on
their own safety times
Note 2 In this case, the pump can stop immediately
Fig. 5.d
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