19
RICKARD 2019
MLM INTEGRATION WITH BMS
Note:
It is important to distinguish between the three ‘BMS command’ tabs indicated. The ‘Process/BMS’ tab is
for selecting manual or external BMS commands. The ‘RTC/Backoff BMS’ tab is exclusively for RTC driven
operations. ‘RTC/ Pre_Post BMS Cmd’ tab is for RTC functions where a pre/post timer period is required.
For any control override command to execute, the Master Command/Control override flag must be ena-
bled.
If a system is required to execute a control override command after hours only, the ‘Process/BMS com-
mand’ check boxes should all be cleared.
RTC control override operation
Once the control override start time is reached, typically after working hours, the MLM24 system will check if a
pre-timer period was set. If so, the pre-BMS selection will be executed. In conjunction the indicator button at
the bottom of the Wallstat screen will switch from WH (working hours) to AH (after hours).
Once the pre-timer period has lapsed or if it is set to zero, the system will execute the control override BMS
selection.
On conclusion the post-BMS action will be activated if the post timer was set. The pre- and post-timer periods
are implemented if there is a requirement to condition an area prior to back-off or back-on. Following this op-
tional period the system will revert to normal control and the indicator will switch back from AH to WH.
RTC control override Command Table:
Func on
Descrip on
Open
Drive Diffuser Open to pre‐set limit posi on, heater off
Close
Drive Diffuser Close to pre‐set limit posi on, heater off
Emergency
Emergency, this command will disable the heater output
Emergency & Open
Disable heater output and drive diffuser completely open
Emergency & Close
Disable heater output and drive diffuser completely closed
Backoff Ac ve
Ac vate WH or AH dead band back‐off control, whichever is applicable
Max Heat
Drive diffuser to supply air maximum heat posi on and switch heater 100% on
Occ Backoff Ac ve
Status flag to indicate the system is in unoccupied control mode
Occupancy sensor description
The MLM24 system makes use of PIR (Passive Infra-Red) technology to detect an occupied/unoccupied state.
The PIR sensors are mounted unobtrusively on the diffuser trim disk to cover the normal diffuser ‘throw’ area.
These sensors are also fitted to Wall thermostats as an additional option for occupancy detection.
The number of sensors mounted per control zone is determined by the detection area, and ranges from one per
control zone to one per diffuser and Wallstat units. The sensor signals are combined in an ‘or’ function, which
means that detection picked up by any sensor in a control zone will flag that zone as occupied.
