Metasys N2 to BACnet MS/TP
Quickserver Gateway (Serial-Ethernet)
QuickServer is a high performance, fully configurable, cost effective Building and Industrial Automation gateway for integrators to easily interface devices to networks in commercial buildings and industrial plants.
System integrators world-wide have benefitted from the value of the powerful line of interoperability gateways offered by FieldServer. Now, QuickServer adds to that value by running the same robust FieldServer protocol conversion software on a highly cost effective platform backed by the experience, engineering expertise and proven technical support that integrators have come to expect from FieldServer.
QuickServer is available in two series. The FS-QS-10XX Series is preloaded with two BAS drivers (serial, Ethernet and/or LonWorks) from a choice of Modbus RTU, Modbus TCP, BACnet/IP®, BACnet MS/TP, LonWorks®, JCI Metasys® N2 and SNMP. Each QuickServer can handle up to 250 points.
The FS-QS-12XX Series QuickServer is available to use any Serial, Ethernet or LonWorks driver in the extensive FieldServer driver library. The FS-QS-12XX Series can handle up to 500 points and is available with a choice of RS-485, RS-232 or RS- 422 serial ports, KNX or M-Bus, in addition to Ethernet and LonWorks (optional).
Each QuickServer includes browser-based tools to make it easy to set-up
QuickServer and perform diagnostics including determination of status, network
settings, node information, map descriptors and more. The USB flash drive also
includes the Discovery utility to determine what FieldServers are on a network.
The Metasys® N21 by Johnson Controls network supports communications with a diverse range of devices. Many N2 compatible devices use their own version of the protocol and care must be taken to ensure that the device of interest is covered by the FieldServer implementation.
At present the FieldServer Metasys® N2 driver will support communications with the following devices or classes of devices when acting as a Client:
- N2Open-compliant devices. N2Open is a published N2-compatible protocol enabling 3rd party device vendors to integrate with N2.
- VMA 1400 series (with restrictions)
- DX9100 and XT9100
When acting as a Server the FieldServer Metasys® N2 driver can emulate an N2Open device only.
The BACnet Master-Slave/Token-Passing (MS/TP) driver implements a data link protocol that uses the services of the RS-485 physical layer. See the FieldServer BACnet PIC statement for the level of conformance that this driver implements.
All information in a BACnet system is represented in terms of objects. The Object_Identifier is a 32-bit code that identifies the type of Object (also identified by the Object_Type Property) and its "Instance" number, which together uniquely identify the Object within its BACnet device. Theoretically, a BACnet device could have over four million Objects of a particular type. The Object_Name is a text string, which has a unique capability. BACnet devices may broadcast queries for devices that contain Objects with a specific Object_Name. This can greatly simplify project setup.
BACnet requires one Device Object to be present in every BACnet device. The Device Object makes information about the device and its capabilities available to other devices on the networks. Before one BACnet device starts control-related communications with another, it needs to obtain some of the information presented by the other device's Device Object. Unlike other Objects, the Device Object's Instance number must be unique across the entire BACnet internetwork because it is used to uniquely identify the BACnet devices. It may be used to conveniently identify the BACnet device from other devices during installation.
Standard object types are used to hold real time data and other information. Each Object Type is referenced by a number, for example 0 represents an Analog Input.
Each Object consists of a number of prescribed properties, the main property being the Present_Value. Objects are monitored and controlled through their properties. The Analog Input Object is representative of the Objects involved directly with control elements and many of its Properties reflect this.
The information that follows describes how to expand upon the factory defaults provided in the
configuration files included with the FieldServer.
QuickServer Start-up Guide
FS-8700-73_BACnetMSTP Driver manua Rev2.01_2015
FS-8700-19 Metasys N2 by Johnson Controls Protocol Manual
QuickServer Start-up Guide
QuickServer Data Sheet
FS Application Note - Bacnet Protocols supported by FieldServers
FS-8700-19 Metasys N2 by Johnson Controls Protocol Data Sheet
QuickServer Data Sheet
Metasys N2 by JCI - ComBus Quick Tester Manual
Johnson Controls Metasys N2 Communications Interface Technical Manual
Metasys N2 by JCI - N2 Communication Bus Tech Bulletin
Metasys N2 by JCI - UNT110 UNT111 controller
Metasys N2 by JCI - checksum analysis
Metasys N2 by JCI - HVAC_PRO_help files
Metasys N2 by JCI - Device Points
Metasys N2 by JCI - DX9100 ConfigGuide
Metasys N2 by JCI - DX9100 Wiring
Metasys N2 by JCI - NAE Configuration
Metasys N2 by JCI - Metasys Unitary Controller (UNT)
Metasys N2 by JCI - vma1420
BACnet MSTP to IP
A BACnet Router is used to connect MSTP trunks to BACNetIP systems. The router itself is a device on the IP and on the MSTP side. The router can also act as BBMD device allowing messages to cross from one subnet to another.
BACnet messages cannot cross from one subnet to another except under special circumstances.
Most BACnet sequenc es of messages begin with a broadcast called 'who is'. All devices respond with 'I am'. That is how they are discovered. It is also how many system confirm the device is still there.
Broadcasts cant cross routers (they are blocked) and therefore devices on the other side of a router cannot e discovered.
BBMD is the name of the BACNet technology that resolves these issues. The BACNet ROuter sold by CAS provides BBMD services as do all FieldServer BACNet products when configured as clients.