NuAire EcoSmart Connect Control User Manual

7
15. 02. 22. Document Number 672040
Nuaire | Western Industrial Estate | Caerphilly | CF83 1NA | nuaire.co.uk
BPS H-CO
Installation Manual
1.34 Writing Of Values (Priority Array)
Any device on the BACnet network can write values to other device
objects. To resolve conflicts, BACnet uses a 16-position priority array to
work out who gets priority. Any request it change the present value is
stored in the priority array at the priority level of the received request.
The object then chooses the highest priority value to become the
present value. Examples of priority array decision making are shown
below.
Case 1
Priority 1 null
Priority 2 null
Priority 3 null
Priority 4 null
Priority 5 null
Priority 6 null
Priority 7 null
Priority 8 null
Priority 9 null
Priority 10 null
Priority 11 null
Priority 12 null
Priority 13 null
Priority 14 null
Priority 15 null
Priority 16 null
Relinquish
Default
0
Present
Value
0
Case 2
Priority 1 null
Priority 2 null
Priority 3 null
Priority 4 null
Priority 5 null
Priority 6 null
Priority 7 null
Priority 8 null
Priority 9 null
Priority 10 null
Priority 11 null
Priority 12 null
Priority 13 null
Priority 14 null
Priority 15 null
Priority 16 5
Relinquish
Default
0
Present
Value
5
Case 3
Priority 1 null
Priority 2 null
Priority 3 null
Priority 4 null
Priority 5 null
Priority 6 null
Priority 7 null
Priority 8 null
Priority 9 7
Priority 10 null
Priority 11 null
Priority 12 null
Priority 13 null
Priority 14 null
Priority 15 null
Priority 16 5
Relinquish
Default
0
Present
Value
7
Case 4
Priority 1 null
Priority 2 null
Priority 3 null
Priority 4 null
Priority 5 null
Priority 6 null
Priority 7 null
Priority 8 null
Priority 9 7
Priority 10 null
Priority 11 null
Priority 12 null
Priority 13 null
Priority 14 null
Priority 15 null
Priority 16 0
Relinquish
Default
0
Present
Value
7
Case 4
Priority 1 null
Priority 2 null
Priority 3 null
Priority 4 null
Priority 5 null
Priority 6 null
Priority 7 null
Priority 8 null
Priority 9 null
Priority 10 null
Priority 11 null
Priority 12 null
Priority 13 null
Priority 14 null
Priority 15 null
Priority 16 0
Relinquish
Default
0
Present
Value
0
•Case 1 - The object looks down the list until it gets to the first
non-null value. In this case, all priority levels are empty so the
(relinquish) default value of 0 is used as the present value.
•Case 2 - Priority 16 is now 5 so the present value becomes 5.
•Case 3 - Priority 9 is now 7. Priority 9 overrules priority 16 so the
present value becomes 7. Note that priority 16 is still calling for 5
but it is being ignored.
•Case 4 - Priority 16 is changed to 0 but this has no effect on the
present value. It is still at 7 because of priority 9.
•Case 5 - Priority 9 is relinquished back to null. This allows priority
16 to take priority again and the present value becomes 0.
The priority array is stored inside the device itself. This means that an
external device can write to a priority position and the value will stay
there even if the device is disconnected.
AI and BI object types are read only and therefore do not have a priority
array.
AO & BO values are typically changed by the strategy at priority level
16. Any override must occur above this level and is not recommend. Be
sure to relinquish all overrides once finished to minimise confusion and
undesirable operation.
AV, BV & MSV values are generally not changed by the strategy so an
external command at priority level 16 is sufficient to change the value
permanently.
The following table shows the standard use of the priority array.
Priority Application
1 Manual Life Safety
2 Automatic Life Safety
3 Available
4 Available
5 Criticial Equipment Control
6 Minimum On/Off
7 Available
8 Manual Operator
9 Available
10 Available
11 Available
12 Available
13 Available
14 Available
15 Available
16 Available
1.35 Inter-Networking
Inter-networking is used to connect two BACnet networks operating on
different physical mediums (e.g. MSTP & IP). This is possible because no
matter the physical medium, BACnet messages are always the same.
A router can be fitted to the network to translate BACnet between
different physical media.
1.35.1 Example BACnet Network
6
Example BACnet Network
This is a typical example of a BACnet
network.
Not all objecs or properties are shown
for clarity.
Controller
(MSTP address 4)
Device Properties
Object Name: Office 1 Controller
Object Instance: 12222
Description: Office 1 Controller
Location: Office 1
Controller
(MSTP address 5)
Device Properties
Object Name: Office 2 Controller
Object Instance: 12226 Description:
Office 2 Controller
Location: Office 2
Object Properties
Object Name: Room
Air Temp
Object Instance: 10008
Object Type: AI
Present Value: 20.2
Units: °C
Object Properties
Object Name: Humidity
Object Instance: 10104
Object Type: AI
Present Value: 56
Units: Percent
Object Properties
Object Name: Alarm
Object Instance: 17013
Object Type: MSV
Present Value: Normal
State Text: Normal, Alarm
Object Properties
Object Name: Fan Output
Object Instance: 10185
Object Type: AO
Present Value: 0
State Text: Volts
Object Properties
Object Name: Enable
Object Instance: 10288
Object Type: MSV
Present Value: On
State Text: Off, On
Object Properties
Object Name:
Humidity Setpoint
Object Instance: 10104
Object Type: AV
Present Value: 60
State Text: Percent
Object Properties
Object Name: Fan Output
Object Instance: 10182
Object Type: AO
Present Value: 2.8
State Text: Volts
MSTP Connection
Device
Object
Device
Object
Object
Object Object
Object
Object
Object Object

NuAire EcoSmart Connect Control Specifications

General

Brand	NuAire
Model	EcoSmart Connect Control
Category	Controller
Language	English