Daikin D-BACS, Design Manual

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12.6 Monitoring and Control Restrictions 249
Interface for use in LONWORKS
®
12.6 Monitoring and Control Restrictions
12.6.1 Restrictions Regarding the ‘System Forced OFF’ Function
- The LON monitoring nodes send a ‘System Forced OFF’ command to the Interface for LONWORKS
®
.
All of the A/C units on the DIII-NET controlled by the Interface for LONWORKS
®
stop operating.
- A/C units cannot be operated from the hand-held remote controller.
- A/C units cannot be operated from the centralized devices.
- The LON monitoring nodes send a message to deactivate the ‘System Forced OFF’ command to the Interface for
LONWORKS
®
.
All of the A/C units on the DIII-NET controlled by the Interface for LONWORKS
®
can be operated. (allow use of a
remote controller)
- A/C units can be operated from the hand-held remote controller. (status is not restored)
- A/C units can be operated from the centralized devices. (status is not restored)
- When the System Forced OFF command is issued, the hand-held remote controller for the A/C units becomes
‘Inoperable status’. However, the output message of Remote ON/OFF Operation Rejection Report is not sent to the
LON monitoring nodes.
The System Forced OFF status is output as a ‘System Forced OFF Setting Report’.
- There is one System Forced OFF contact point per A/C control network (DIII-NET) line. Input in the Interface for
LONWORKS
®
is conducted either contact input or via the LON. Moreover, the centralized device for the System
Forced OFF input point is set as the DIII main A/C unit.
- When the System Forced OFF Reset command and A/C Operation command from the
LON monitoring nodes are sent at, more or less, the same time, the latter may not be properly sent to the A/C units.
The entire A/C control network (DIII-NET) controlled by the Interface for LONWORKS
®
becomes System Forced OFF
reset status, so the operation command for the A/C units may be rejected. If the A/C Operation command is to be sent
after deactivation (reset), it is recommended that it be issued after confirming that the System Forced OFF has
actually been deactivated (reset).
LON communications do not and cannot guarantee the startup order of processing when more than one
status change are reported.
12.6.2 Operation Mode Changeover Restrictions
- When the Operation Mode Changeover command and Temperature Setting command from the LON monitoring
nodes are sent at, more or less, the same time, the latter may not be properly sent to the A/C units.
<Example>
1. Changeover command from cooling to heating
2. Temperature Setting command in the heating mode: Change to 20
°
C
3. Completion of temperature setting at 20
°
C in the heating mode
1. Set temperature is changed first: Change to a 20
°
C in the cooling mode
2. Changeover from cooling to heating
3. Completion of temperature setting at the default value (initially set temperature) in the heating mode
It is recommended that the commands to change the set temperature be issued after confirming the Operation Mode
Changeover command has actually been sent and processed.
LON communications do not and cannot guarantee the startup order of processing when more than one status
change are reported.
The system still cannot be operated.