AS-B

Introduction

At the core of a SmartStruxure solution is a SmartStruxure server device, such as AS-B. AS-B performs key functionality, such as control logic, trend logging, and alarm supervision, provides built-in I/O, and supports communication and connectivity to the field buses. The distributed intelligence of the SmartStruxure solution ensures fault tolerance in the system and provides a fully featured user interface through WorkStation and WebStation.

Feature

AS-B is a powerful device with built-in power supply and I/O. AS-B can act as a standalone server using its built-in I/O and also monitor and manage field bus devices. In a small installation, the embedded AS-B device acts as a standalone server, mounted in a small footprint. In medium and large installations, functionality is distributed over multiple SmartStruxure server devices that communicate over TCP/IP.

Capable of coordinating traffic from above and below its location, AS-B can deliver data directly to you or to other servers throughout the site. AS-B can run multiple control programs, manage built-in I/O, alarms, and users, handle scheduling and logging, and communicate using a variety of protocols. Because of this, most parts of the system function autonomously and continue to run as a whole even if communication fails or individual SmartStruxure servers or devices go offline.

AS-B comes in four models with different I/O point count and I/O mix.

AS-Bs with “H” in the product name are equipped with a display for output override.

AS-Bs with 36 I/O points have the same small footprint as AS-Bs with 24 I/O points, but with 50 percent higher I/O point count.

AS-B offers a mix of I/O point types that match most types of HVAC applications. Most I/O points are highly flexible and can be configured as either inputs or outputs.

AS-Bs with 24 I/O points have the following types:

• 12 Universal inputs/outputs, Ua type

• 4 Universal inputs/outputs, Ub type

• 4 Digital inputs

• 4 Relay outputs

AS-Bs with 36 I/O points have the following types:

• 20 Universal inputs/outputs, Ua type

• 8 Universal inputs/outputs, Ub type

• 4 Triac outputs

• 4 Relay outputs

The universal inputs/outputs are ideal for any mix of temperature, pressure, flow, status points, and similar point types in a building control system.

The universal inputs/outputs can be configured to read several different types of inputs:

• Digital

• Counter

• Supervised

• Voltage

• Current (Ub only)

• Temperature

• Resistive

• 2-Wire RTD temperature

• 2-Wire RTD resistive

As counter inputs, the universal inputs/outputs are commonly used in energy metering applications. As RTD inputs, they are ideal for temperature points in a building control system. As supervised inputs, they are used for security applications where it is critical to know whether or not a wire has been cut or shorted. These events provide a separate indication of alarms and events in the system.

For all analog inputs, maximum and minimum levels can be defined to automatically detect over-range and under-range values.

The universal inputs/outputs are capable of supporting analog outputs of type voltage outputs. Therefore, the universal inputs/outputs support a wide range of devices, such as actuators.

The digital inputs can be used for cost effective sensing of multiple dry contact digital inputs in applications, such as equipment status monitoring or alarm point monitoring. As counter inputs, digital inputs are commonly used in energy metering applications.

The relay outputs support digital Form A point types. The Form A relays are designed for direct load applications.

The triac outputs can be used in many applications to switch 24 VAC on or off for external loads such as actuators, relays, or indicators. Triacs are silent and do not suffer from relay contact wear.

AS-Bs with “H” in the product name are equipped with an LCD display and keys to support manual override control of analog and digital outputs. This function allows you to manually override the outputs for testing, commissioning, and maintenance of equipment.

The override configuration is readable through user interfaces, such as Building Operation WorkStation, enabling more precise monitoring and control.

The device has a built-in power supply designed to accommodate 24 VAC or 24 VDC input power. The main AC/DC input (L/+ and N/-) is galvanically isolated from the electronics. This removes the risk of damage due to earth currents and permits the input power to be wired without concern for polarity matching.

AS-B has numerous ports that enable it to communicate with a wide range of protocols, devices, and servers.

AS-B has the following ports:

• Two 10/100 Ethernet ports

• One RS-485 port

• One USB host port

• One USB device port

The two Ethernet ports are connected to a built-in Ethernet switch. One port should be connected to the site network. The other port can be used to connect a single WorkStation or WebStation, a Modbus TCP unit, or a BACnet/IP device, but not another SmartStruxure server.

The USB device port allows you to upgrade and interact with AS-B using Device Administrator. The USB host port can be used to provide power and communications for the AD touchscreen display.

A SmartStruxure solution provides a powerful permission system that is easy to manage, flexible, and adapts to all kinds of system sizes. The permission system provides a security level to the highest standards. Authentication is done against the built-in user account management system or against Windows Active Directory Domains. The built-in account management system allows an administrator to set password policies that meet stringent CyberSecurity guidelines. When Windows Active Directory is used, the administration costs are lower because users do not have to be managed in multiple directories.

Through any client, the user experience is similar regardless of which SmartStruxure server the user is logged on to. The user can log directly on to AS-B to engineer, commission, supervise, and monitor AS-B and its built-in I/O as well as its attached field bus devices. See the WorkStation and WebStation specification sheets for additional information.

One of the cornerstones of SmartStruxure solution is support for open standards. AS-B can natively communicate with two of the most popular standards for buildings: BACnet and Modbus.

AS-B communicates directly to BACnet/IP and BACnet MS/TP networks. AS-B is BTL-listed as a BACnet Building Controller (B-BC), the most advanced BACnet Device Profile. This capability provides access to an extensive range of BACnet devices from Schneider Electric and other vendors. See the BTL Product Catalog for up-to-date details on BTL listed firmware revisions on BACnet International's home page. AS-B can also serve as a BACnet Broadcast Management Device (BBMD) to facilitate BACnet systems that span multiple IP networks.

AS-B natively integrates Modbus RS-485 master and slave configurations, as well as Modbus TCP client and server. This allows full access to third-party products and the range of Schneider Electric products that communicate on the Modbus protocol, such as power meters, UPS, circuit breakers, and lighting controllers.

AS-B supports the use of Web Services based on open standards, such as SOAP and REST, to consume data into the SmartStruxure solution. Use incoming third-party data (temperature forecast, energy cost) over the Web to determine site modes, scheduling, and programming.

EcoStruxure Web Services, Schneider Electric’s Web Services standard, is natively supported in AS-B. EcoStruxure Web Services offers extra features between compliant systems whether within Schneider Electric or other authorized systems. These features include system directory browsing, read/write of current values, alarm receipt and acknowledgement, and historical trend log data. EcoStruxure Web Services is secure. User name and password are required to log on to the system.

Unique to the industry, AS-B has both Script and Function Block programming options. This flexibility assures that the best programming method can be selected for the application.

The SmartStruxure server device has a 4 GB eMMC memory, which is used for the server application, historical data, and backup storage. Users can also manually back up or restore the SmartStruxure server device to a storage location on a PC or network. Through the Enterprise Server, users have the ability to perform scheduled backups of associated SmartStruxure server device to network storage for even greater levels of protection.

AS-B communicates using the networking standards. This makes installations easy, management simple, and transactions secure.

Communication between clients and the SmartStruxure servers can be encrypted using Transport Layer Security (TLS 1.2). The servers are delivered with a default self-signed certificate. Commercial Certification Authority (CA) server certificates are supported to lower the risk of malicious information technology attacks. Use of encrypted communication can be enforced for both WorkStation and WebStation access.

• IP addressing

• TCP communications

• DHCP for easy network configuration

• DNS for simple lookup of addresses

• HTTP/HTTPS for Internet access through firewalls, which enables remote monitoring and control

• NTP (Network Time Protocol) for time synchronization throughout the system

• SMTP or SMTPS with support for SSL/TLS based authentication, enables sending email messages triggered by schedule or alarm

• SNMP enables network supervision and reception of application alarms in designated network management tools

Fasteners easily snap into a locked position for panel installation. The fastener has a quick-release feature for easy DIN-rail removal.

AS-B uses pluggable terminal blocks, which are easy to install and remove from the device. The terminal blocks are delivered with the device.

The input and output terminals are clearly labeled. The Building Operation WorkStation software can generate custom as-built labels for AS-B.

Protection components on the universal inputs/outputs, digital inputs, and triac outputs protect against high-voltage short-duration transient events. Universal inputs/outputs configured as current inputs (Ub only) are protected against over current. Universal inputs/outputs configured as voltage outputs have current limits to protect against permanent short-circuit to ground.

Terminals

 

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AS-B model with 24 I/O points

 

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AS-B model with 36 I/O points

For protection from excess current that could be produced by field wiring, follow these instructions:

• Connect RET terminal number 4 or 5 to a common chassis/signal ground rail in the control panel using a size 2.5 mm² (13 AWG) or larger wire. The wire must have a current rating greater than or equal to 16 A.

• AS-Bs with 24 I/O points have more RET terminals for connection of I/O returns, so the common chassis/signal ground rail is optional and may not be needed.

• Individual 24 VDC power sources to the field must be current limited to maximum 4 A for UL compliant installations, and maximum 6 A in other areas.

For more information on wiring, see Hardware Reference Guide.