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Concept Concept 7/31/2017
Products: AS-B
Functionalities: Hardware
Product version: 1.9


AS-B is a powerful SmartStruxure server device that features both onboard I/O and built-in power supply. Like the other SmartStruxure server devices, AS-B is a Schneider Electric manufactured embedded device that generally serves as the lowest tier SmartStruxure server within the SmartStruxure solution. The SmartStruxure server device controls and supervises equipment, typically HVAC equipment. AS-B uses its onboard I/O with connected field devices, such as sensors and actuators, to do that.

AS-B is installed on DIN rails in cabinets. Power is supplied through the built-in power supply.



AS-B Models

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


I/O Points

















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

AS-Bs with “L” in the product name do not support Modbus, BACnet MS/TP, or hosting of BACnet/IP devices. The RS-485 port is not used.

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 Onboard I/O

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.

For more information, see AS-B Onboard I/O .

Output Override Function

The output override function allows you to manually override outputs. This function can be used for testing, commissioning, and maintenance of equipment.

For more information, see Output Override Function .

Built-in Power Supply

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 two types of memory:

  • 256 MB DDR2 SDRAM (for program execution)

  • 4 GB eMMC memory (for storage)

If a power failure occurs, all important variables are automatically saved to the eMMC memory before complete shutdown. When power returns, this data retention function ensures that AS-B can continue to run with the correct set of values.

Supported Building Standards

AS-B natively communicates with two of the most popular communication protocols:

  • BACnet: AS-B directly communicates to BACnet/IP and BACnet MS/TP networks, which provides access to b3 devices and BACnet devices.

  • Modbus: AS-B natively integrates Modbus RS-485 master and slave configurations, as well as IP client and server. This integration provides access to devices that communicate on the Modbus protocol, such as power meters, circuit breakers, and lighting controllers.

AS-B Communication Ports

AS-B has the following communication ports:

  • 2 Ethernet 10/100 megabit ports

  • 1 RS-485 port

  • 1 USB host port

  • 1 USB device port

For more information, see AS-B Communication Ports .

AS-B Screw Terminals

AS-B uses pluggable terminal blocks, which are easy to install and remove from the device. The terminal blocks are ordered separately from Schneider Electric.

For more information, see AS-B Screw Terminals .


There are five LEDs on the front panel of AS-B.

For more information, see AS-B LEDs .

Reset Functions

There are three different types of reset for the SmartStruxure server devices: warm start, cold start, and DFU mode. Depending on the type of reset, the SmartStruxure server device can be reset using the reset button or a command from WorkStation.

For more information, see Reset Functions .

Device Installation

The AS-B devices are designed for installing on DIN rails in a cabinet.

For more information, see AS-B Device Installation .


The wiring recommendations provide guidance regarding wiring of the I/O modules and the SmartStruxure server devices.

For more information, see Wiring .

AS-B Software

Before you engineer AS-B, install the AS-B software on the server using Device Administrator. The software is not pre-loaded on AS-B.

For more information, see Installing AS-P or AS-B Software .

SmartStruxure Server Device Replacement Using Restore

Backup and Restore assures that SmartStruxure server devices data can be restored to a replacement SmartStruxure server device in the event of hardware failure, or to the same SmartStruxure server device in the event of data loss. As a precaution, you back up your SmartStruxure server devices regularly so that you can use the most current backup to restore the SmartStruxure server devices data to a replacement SmartStruxure server device. You also configure the new SmartStruxure server device to match the name and the network settings of the replaced SmartStruxure server device so the system can identify this SmartStruxure server device when online.

For more information, see SmartStruxure Server Device Replacement Using Restore .

AC input
Nominal voltage
24 VAC
Operating voltage range
+/-20 %
50/60 Hz
Maximum current
0.5 A rms
Recommended transformer rating
≥15 VA
DC input
Nominal voltage
24 to 30 VDC
Operating voltage range
21 to 33 VDC
Maximum power consumption
10 W
Ambient temperature, operating
0 to 50 °C (32 to 122 °F)
Ambient temperature, storage
-20 to +70 °C (-4 to +158 °F)
Maximum humidity
95 % RH non-condensing
Plastic rating
Enclosure rating
IP 20
198 W x 110 H x 64 D mm (7.8 W x 4.3 H x 2.5 D in.)
Weight, including terminal blocks
0.504 kg (1.111 lb) a
a) The weight includes the display and keys, which are 0.022 kg (0.049 lb).
Weight, excluding terminal blocks
0.420 kg (0.926 lb) a
a) The weight includes the display and keys, which are 0.022 kg (0.049 lb).
Real-time clock backup
Inaccuracy, at 25 °C (77 °F)
+/-52 seconds per month
Backup time
10 days
Communication ports
Dual 10/100BASE-TX RJ45
USB 2.0, 1 device port (mini-B) and 1 host port (type-A)
2-wire port, bias 5.0 VDC
BACnet/IP and MS/TP, port configurable, default 47808
BTL B-BC (BACnet Building Controller) a
a) See the BTL Product Catalog for up-to-date details on BTL listed firmware revisions on BACnet International's home page.
Modbus TCP, client and server
Serial, RS-485, master or slave
Binary, port fixed, 4444
Non-binary, port configurable, default 80
Encrypted supporting TLS 1.2, 1.1, and 1.0, port configurable default 443
Email sending, port configurable, default 25
version 3
Network supervision using poll and trap
Application alarm distribution using trap
333 MHz
SPEAr320S, ARM926 core
256 MB
eMMC memory
4 GB
Memory backup
Yes, battery-free, no maintenance

Internal Configuration

The AS-B internal configuration with regards to the signal ground is shown in the following figure.

AS-B internal configuration

AS-B internal configuration

The earth ground terminal ( ) of the built-in power supply is connected to signal ground, which is the same as the negative output from the power supply. The purpose of this connection is to comply with EMC directives.

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