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RICKARD 2019
MLM INTEGRATION WITH BMS
MLM Control Override Handling Procedure
The MLM24 system contains three internal processes for activating system control override, or back-off from
normal control. There is a manual control override command entered through the MLM Tool application, a Real
Time Clock operation for after-hours detection and operation and an Occupancy sense feature. Any external
BMS process such as BACnet connected to the MLM24 system will take precedence over an internal back-off/
override process currently in operation.
Please note that these control override features are enabled per control zone, i.e. each individual master
controller unit must be activated, either zone specific or global (All) commands by the MLM Tool. Note
that after selection the ‘Write’ button must be pressed to activate a command.
The following explanation makes use of the MLM Tool revision 8.14 or above. During the setup procedure
it is assumed the MLM Tool is actively communicating to a field diffuser system and the system is syn-
chronised.
Conventionally an external ‘BMS (Building Management System) command’ would force a specific ‘control
override’ action on the MLM24 system. These same control override actions can also be generated by the
MLM24 internal processes and are therefore indicated under the same naming tabs.
Most of the control override commands require the Diffuser controller to set the actuator and heater driv-
ers into a manual operation mode, with the diffuser icons then displayed in yellow.
Manual control override activation
The manual control override feature allows the user to enter specific control override commands by using the
MLM Tool.
Manual control override can be commanded by accessing either a Wallstat or an On-board master unit:
Expand the Wallstat or the on-board master host diffuser icon in the Logical screen. On type 7 (WS) or 8
(On-Board) click on Process/BMS command and select the action required during control override. Press
Write. See the BMS Command table below. Note these flags also double as status indicators should an
external BMS command be active, e.g. a BACnet BMS command received via the MCU.
