|How it works
75F® CCU to act as the front-end control for Daikin Maverick or Rebel RTU units. Using the local API connection between the CCU and the IE gateway you are now able to control DAT setpoint, schedules, Duct static pressure, & Humidity as well as report back alarm status and other points from the RTU.
- Daikin IE gateway
- Daikin RTU with Micro Tech 3 unit controller
- CCU with cloud subscription connected to building Wi-Fi.
- IE Subscription for first 90 days is required, Annual subscription is not required
- CCU communicates with building sensors over 900 MHz mesh
- CCU connect to IE gateway over wired ethernet connection.
- IE Gateway connect to MicroTech3 controller in the RTUCCU.
- CCU communicates to 75F cloud over Building Wifi.
- 75F Remote apps connect to the 75F cloud.
Following are the type of operation that can be performed using the Daikin IE RTU
CCU reads the alarm information from the IE GW and relays the same to cloud. CCU reads three separate alarm levels These alarm conditions originate in the equipment PLC and is relayed via the IE GW to the CCU. And 75F portals and apps. They return a numeric value that corresponds to a description of the alarm condition. This description is not be mapped to the UI at initial launch and the user only sees an alarm code on the CCU and web UI.
- Warning alarms is in the range of 0-99 and is mapped to 'Low' severity alerts. These alarms do not affect unit operation
- Problems is in the range of 100-199 and mapped to 'Moderate' severity alerts. These alarms limit functionality in some way on the equipment.
- Faults is in the range of 200-255 and mapped to 'Severe' severity alerts. These alarms cause the equipment to shut down.
- In cases where only one alarm for a piece of equipment can be displayed, the ActiveAlarmEnu is displayed and represents the highest priority active alarm. This is in the range of 0 – 255 and mapped to ‘Moderate’ severity alerts.
75F communicates the CCU schedule to the IE GW. To do this 75F changes the point 'OccMode' on the IE GW. When schedule is occupied or unoccupied-conditioning is required, 'OccMode' to be changed to 'Occ' When unoccupied and no conditioning is required, 'OccMode' changed to 'Unocc'. CCU shall control the RTU occupancy by writing to “OccMode” from “unocc” (1) to “occ” (0) and back again, based on CCU and solution occupancy status. This is written every minute to the IE GW irrespective of the 'OCCSTATUS'.
CCU reads the "OCCSTATUS" (Occupancy Status) from IE GW and relays the same value to cloud. Occupancy Status give the status of occupancy on IE GW. This value is read every 5 min by CCU. CCU and Cloud UI displays the occupancy status as read from IE GW.
Cooling / Heating Mode Changeover
Unit is switched to Fan Only Mode to save energy when conditioning is not required. This requires writing to the point NetApplicMode (Application Mode). When the average space temps are relatively satisfied & CCU determines that no conditioning is required, the Application Mode is changed from 'Auto' to 'Fan Only'. When again CCU determines conditioning is required then Application Mode is changed to 'Auto'. This is how we switch the unit into 'Auto' and 'Fan Only' Mode so that we are not always using energy when temps are relatively satisfied.
Discharge Air Temperature Control
Cooling/Heating is achieved by writing to the point DATClgSetpoint. 75F controls the DAT setpoint by directly writing to DAT Cooling Setpoint (F) (DATClgSetpoint). This value is scaled for both heating and cooling DAT setpoint. So DATClgSetpoint can require heating or cooling and is used to heat or cool. This value is written once a minute. RTU controller does not transition to a heating mode, but activates “Min DAT” mode when necessary to maintain “DATClgSetpoint” with heat rather than cooling (this happens when control temp source is set to none).
When there is a need for cooling, cooling is achieved when the cooling loop output is written to the DATClgSetpoint. Cooling loop output shall be 0-100% which is mapped to 70 - 55 deg F of DAT setpoint. E.g. when cooling is required and cooling loop output is 0% then value as 70 is written and when it is 100% then value as 55 is written to DATClgSetpoint.
When there is a need for heating, heating is achieved when the heating loop output is written to DATclgSetpoint. Heating loop output shall be 0-100% which is mapped to 75 - 100 deg F of DAT setpoint. E.g. when heating is required and heating loop output is 0% then value as 75 is written and when it is 100% then value as 100 is written to DATClgSetpoint.
CCU controls fan speed for both single zone and multi zone systems. the toggle to select if the system is single zone or multi-zone in the configuration page helps to achieve this. This is enabled manually by the user based on actual site configuration. At any time CCU shall write values for either single zone or multizone system points. For a single zone system CCU fan loop output shall be mapped to Fan Speed (RemoteSFCap) and for multizone system CCU fan loop output shall be mapped to duct pressure setpoint (DSPspt).
When Humidity control is enabled on the 75F CCU, the Dehum Mode (HumidityCtrl) is set to Rel Hum (1) and to None (0) when Control Humidity is not enabled on 75F [Only on Change of State].
75F writes the humidity reading as an average of all active 75F space humidity sensors [1min] to Relative Humidity Input (BACnetRH) .75F also writes the setpoint for relative humidity setpoint (HumiditySPT) if applicable [Only on Change of State] .
If dehumidification is required 75F must write the application mode switches to auto during unoccupied mode.
Standalone Mode (Fail Safe) for Daikin
When Control Temp Source is set to 'None' in MT3, the unit currently has no backup mode. When 75F is the Primary source of control we rely on no system failures. If there is a failure with 75F hardware or the IE gateway the unit remains in its last known state. This means the building could run away or not run at all when a failure occurs. This is reasoning for creating a standalone failsafe mode.
The assumption is that 75F is sending the DAT Cooling Setpoint (DATClgSetpoint) once a minute as long as the unit is alive. Microtech recognizes this point write as the heartbeat confirming communication between 75F and Daikin. When DATClgSetpoint has not been written to IE Gateway for 5 consecutive minutes, it is assumed that the CCU has lost communication to the gateway and then the IE applies the following settings until IE receives a new DATClgSetpoint heartbeat from 75F.
- Control Temp Source (CtrTempSrc) is changed to 'RAT'. (Note- This needs to be changed back when 75F reconnects)
- For multizone system, Duct Static Pressure Setpoint (inches w.c.) (DSPSpt) is set to 1.0" w.c. (Note- Maybe need to reset our controller to 1" when we do reconnect)
- For Single Zone system, Fan speed maintains its last command if communication is lost.
- Control Mode (AppMode) is set to 'Auto'
- Occupy Mode (OccMode) is set to 'Occ'
- BACnet RH is set to 50%
When Daikin IE receives a new heartbeat from 75F all values are overwritten and the heartbeat count starts again.
Heartbeat for 75F
The “System Clock" point is read by the CCU periodically to determine the DAT setpoint the PLC is currently controlling to. This is provided as a reference for troubleshooting control related issues and is not used for control purposes. The clock Variable point can be used as a primary "heartbeat" for CCU to check communication between IE gateway and CCU.
Note : Initial configuration shall be set on the RTU before configuring CCU: (to be done by Daikin support person)
- Set Control Mode (CtrlMode) to 'Auto'
- Set Control Type (CtrlType) to 'DAT'
- Set Control Temp Source (CtrlTempSrc) to 'None'
- Set Cooling Reset (ClgDATReset) to 'None'
- Set Heating Reset (HtgDATReset) to 'None'
- Control Temperature (OccHtg and OccClg) is set to 68 and 72F
- Set Occupy Mode (OccMode) to “auto”
- Set Supply Air Fan Control (SFCapCtrl) to 'DSP' (Multizone) -OR- 'RemoteSFCap' (Single Zone VAV)
- Dehumidification Method (HumidityCtrl) = Rel_Hum (1) (for units with dehumidification control – have reheat)
- Sensor Loc (SensorLocation) = Space (1)
- CCU and IE Gateway is connected over an ethernet connection directly from 75F CM to Daikin IE gateway. This acts as a subnetwork.
- Fixed IP for Ethernet connectivity would be 172.16.0.1 (Port Eth0) Subnet 255.255.255.0 on IE GW
- Fixed IP for Ethernet connectivity would be 172.16.0.2 Subnet 255.255.255.0 on CCU (172.16.0.10 should be used instead)
- IE Gateway connects to MicroTech3 Controller for the RTU (Port Eth1) 192.168.1.42
- 75F CCU then communicate to 75F cloud over building Wifi. 75F remote apps connects to the 75F cloud
- Cell network should be enabled for 90 days on the IE Gateway.
From the CCU
- Click select system profile
- Select the DAIKIN IE RTU for system profile from the drop down.
The configuration screen displays as below.
The following table explains the various fields displayed on the page:
IE Equipment IP Address
You can use this option to select Ip address of the IE equipment.
Multi Zone Toggle
You can use this option to toggle between a multi zone and single zone.
You can use this option to enable the cooing control
You can use this option to enable the fan control
You can use this option to enable the Heating control
Once configured then you can see the information for the profile as follows.
Once the connection to the cloud is established, you can see the information in the portal as follows.