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7.5
Node#DP2Err
Description
Differential pressure transducer #2
Notification
MT4
Delay
No
Reset type
Automatic
Countermeasure
Check polarity of flow tubes (+/-). Check connection/integrity of transducer board
7.6
Modbus nodes troubleshooting
7.6.1
Node#InOutErr interpretation
Alarms
Node#InOutErr
on MT4 will be notified together with the specific device alarm. Below some examples
of combined notification.
1. Supply temperature sensor, connected to Node4, is broken or not connected.
Node4InOutErr
SplyTmpSenf
2. Return temperature sensor and return fan differential pressure transducer are broken or not connected
Node2InOutErr
Node7InOutErr
RtrnTmpSenf
RtrnFanPressSenf
In order to associate Node#InOutErr with each sensor fault it is necessary to browse the I/O section in the
HMI or examine the wiring diagram.
7.6.2
Node#CommErr behaviour
A whatever node offline error causes AHU Stop.
If a Node must be disabled it has to be physically excluded by the network, disconnecting power and communication
in-out cables. This action is allowed provided that devices on the specific Node are not absolutely essential to the
AHU operation.
This would be the case, for example, of filters.
Note that all Nodes I/O arrangement is the result of an optimization algorithm. In most cases, filters differential
pressure tran
sducers will be placed on the same Node of those of fans. This arrangement doesn’t allow exclusion
of filters Node.
Never modify I/O arrangement of a Node. This will compromise AHU operation!
