Viconics VT8600 Series BACnet Integration Guide - Manual (Page 27)

VT8600 Series BACnet
®
Integration Manual 27
Viconics Technologies Inc. | 9245 Langelier Blvd. | St.-Leonard | Quebec | Canada | H1P 3K9 | Tel: (514) 321-5660 | Fax: (514) 321-4150
028-0437-00 www.viconics.com | [email protected] March 2015
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The polarity of the connection to the cable is important. From one module to the other it is important that the
same colored wire be connected to “plus” or “+” and the other colored wire be connected to the “minus” or
”-“. Figure 7 shows the proper MS/TP connections.
NOTE: The Ref terminal should NEVER be used to wire shields. The 2 shields from each feed of the network
connection to a controller should be wired together in the back of the controller and properly protected to prevent
any accidental connection to the ground.
The joined shield connection should then be grounded at a SINGLE point on the whole segment. More than
one ground connection to a shielded wire may induce ground loop noises and affect communication.
DEFAULT DEVICE NAME AND ID
Default Device Name set to Model number – MAC where:
• MAC is the current MAC address of the device.
• Model number is Viconics part number.
The device name upgrades as soon as there is a change to the device MAC address.
The Device Name and Device ID properties are writable. Both properties can be renamed from any BACnet ®
network management tool as long as the tool itself can write to these properties.
VT8600UXBXX Models
Default Device ID is set to: 86000 + MAC where MAC is the current MAC address of the device.
The device ID upgrades as soon as there is a change to the device’s MAC. For example, when a VT8600 con-
troller with a MAC address of 63 is connected to a network, its default Device ID is 86063.
INTEGRATING VICONICS DEVICES ON A BACNET MS/TP NETWORK
Before doing any BACnet ® integration, make sure you refer to a Viconics PICS document (Protocol Implementation
Conformance Statement). The PICS document lists all the BACnet ® Services and Object types supported by a
device. You can find the document at www.viconics.com.
Viconics devices do not support the COV service. COV reporting allows an object to send out notices when its
Present-Value property is incremented by a pre-defined value. Since this is not supported at Viconics, special
attention should be given to the polling time settings at the Supervisory Controller and Workstation level when
using a graphic interface or an application program to read or write to a Viconics object.
Graphical Interfaces
A graphic interface might poll all data linked to the graphic page on a COV basis. If the third-party device does
not support COV, the graphical interface relies on a pre-configured polling interval, which is usually in hundredths
of milliseconds. Any device containing a monitored object could be subject to network traffic congestion if such a
polling interval is used. Viconics strongly recommends a polling interval of 5 seconds (minimum) for any graphical
interface. This becomes even more critical in graphics where a single representation might poll many devices. If
the proper poll rate is not respected, devices may be reported offline by certain front-ends by saturating the traffic
handling capacity of BACnet® MS/TP without COV subscription.