LEAD-LAG (LL) MODE
Lead-lag (LL) mode shares the same hardware and source code as standalone mode, but offers more
functionality and features. The controller ships from the factory in Standalone Mode. LL mode is configured
manually in the field after the installation. This option allows the user to operate two air conditioners in a staged
cooling configuration. The controller will alternate which air conditioner is the first stage. To support LL mode,
four parameters, H01, H02, H03, and H14 need to be configured. H01 specifies the operating mode, H02 specifies
the device ID, H03 specifies the total number of the units in the group network, and H14 is the LL strategy
selection.
The two controllers is communicated through fieldbus interface as illustrated in Figure 3. In the lead-lag mode
the controller supports
•
Lead-lag staged cooling uses two cooling differential temperature settings Cd1 and Cd2. The lead air conditioner
will begin cooling at SP+Cd1 and the lag air conditioner will begin cooling at SP+Cd1+Cd2. Cooling will stop when
the temperature drops to SP.
•
The two air conditioners will take turns being the lead and lag. Alternating can be done in time based or every
cooling cycle and is configured with H14.
CONNECTING UNITS TOGETHER IN LEAD/LAG MODE
To configure the controller from single mode to LL mode, simply follow below procedures. Perform this
configuration for both air conditioners.
1. Before proceeding the LL mode configuration for each controller, make sure that the communication cable is
connected from one ACU to another using a shielded cable with the shield grounded.
2. Press
button to display passcode screen, the screen displays PSd on line 1 and 0000 on line 2.
3. Press
button to access to passcode , the first digit of 0000 is flashing and press 2 more times until the
third digit 0000 flashes.
Press
arrow two times to change 0 to 2, then press
4. Press
arrow two times to change the 0 to 2.
5. Press
button to access to folder menu and then, the screen displays ALrF
6. Press
arrow to navigate to PArF, then press
7. The screen displays C, press
parameter H menu
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Figure 3: Lead-Lag network connectivity
button to access to parameter menu
arrow to navigate to parameter H and then, press
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button to move to the last digit 0020
button to access to
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