Welcome to the official website of CNIACS Automation Technology Co., Ltd!
0
March 16, 2026 BY
IN ABB

ABB REU 523 secondary relay Overvoltage unit

Overvoltage unit

When the voltage values exceed the set start value of low-set stage U>,  the overvoltage

unit will start to deliver a start signal after a ~60 ms’ start time. When the set operate time

at definite-time characteristic or the calculated operate time at inverse definite mini

mum time (IDMT) characteristic elapses, the overvoltage unit will deliver a trip signal.

When the voltage values exceed the set start value of high-set stage U>>, the overvoltage

unit will start to deliver a start signal after a ~50 ms’ start time. When the set operate time

at definite-time characteristic or the calculated operate time at IDMT characteristic

elapses, the overvoltage unit will deliver a trip signal.

The low-set and the high-set stage of the overvoltage unit can be given either a defi

nite-time or an IDMT characteristic. At IDMT characteristic, two time/voltage curve

groups, A and B, are available.

It is possible to block the tripping of an over voltage stage by applying an external binary

input signal to the relay.

The high-set stage can be set out of operation. This state will be indicated by dashes on the

LCD and by “999” when the set start value is read via serial communication.
March 16, 2026 BY
IN ABB

ABB The over and undervoltage relay REU 523 is a secondary relay

Application

The over and undervoltage relay REU 523 is a secondary relay which is connected to the

voltage transformers of the object to be protected. The over and the undervoltage unit

continuously measure the fundamental wave of the phase-to-phase voltages of the object.

On detection of a fault, the relay will start, trip the circuit breaker, provide alarms, record

fault data, etc., in accordance with the application and the configured relay functions.

The overvoltage unit includes low-set stage U> and high-set stage U>> and the undervolt

age unit low-set stage U< and high-set stage U<<. The high-set undervoltage stage can

alternatively be set to evaluate the positive phase-sequence voltage. In addition, the high

set undervoltage stage can be configured to evaluate only one instead of three phase-to

phase voltages.

The protection functions are independent of each other and have their own setting groups

and data recordings. The over and undervoltage functions use conventional voltage trans

former measurement.

An output contact matrix allows start or trip signals from the protection stages to be

routed to the desired output contact.

Design

The relay includes a high-set and low-set overvoltage unit, a high-set and low-set und

ervoltage unit and a circuit-breaker failure protection unit. Further, the relay includes an

HMI module, a self-supervision system and a disturbance recorder.
March 16, 2026 BY
IN ABB

ABB REU 523 Features

Features

• Single- or three-phase use

• High-set overvoltage stage with definite-time or inverse definite minimum time

(IDMT) characteristic

• Low-set overvoltage stage with definite-time or IDMT characteristic

• High-set undervoltage stage with definite-time or IDMT characteristic

• Low-set undervoltage stage with definite-time or IDMT characteristic

• Positive-phase-sequence protection

• Adjustable drop-off/pick-up ratio for the low-set over and undervoltage stages

• Circuit-breaker failure protection (CBFP)

• Disturbance recorder

• recording time up to 12 seconds

• triggering by a start or a trip signal from any protection stage and/or by a binary

input signal

• records three analogue channels and eight digital channels

• adjustable sampling rate

• Non-volatile memory for

• up to 60 event codes

• setting values

• disturbance recorder data

• recorded data of the five last events with time stamp

• number of starts for each stage

• alarm indication messages and LEDs showing the status at the moment of

power failure

• Three accurate voltage inputs

• Galvanically isolated binary input with a wide input voltage range

• All settings can be modified with a personal computer

• HMI with an alphanumeric LCD and manoeuvring buttons

• IEC 60870-5-103 and SPA bus communication protocols

• Two normally open power output contacts

• Two change-over signal output contacts

• Output contact functions freely configurable for desired operation

• Optical PC-connector for two-way data communication (front)

• RS-485 connector (rear) for system communication

• Continuous self-supervision of electronics and software. At an internal relay fault

(IRF), all protection stages and outputs are blocked.

• User-selectable rated frequency 50/60 Hz

• User-selectable password protection for the HMI

• User-selectable nominal voltage 100/110/115/120 V

• Display of primary voltage values

• Demand values

• Multi-language support
March 16, 2026 BY
IN ABB

ABB REU 523 Combined Overvoltage and Undervoltage Relay

The REU 523 is intended for overvoltage and undervoltage protection in medium

voltage distribution networks but can also be used for protection of generators,

motors and transformers.

The REU 523 continuously evaluates the fundamental wave of the three phase-to

phase voltages. In addition, the high-set undervoltage stage can be configured to

evaluate either only one instead of three phase-to-phase voltages or the

positive-phase-sequence voltage.

The REU 523 is based on a microprocessor environment. A self-supervision system

continuously monitors the operation of the electronics and the software.

The HMI includes a Liquid Crystal Display (LCD) which makes the local use of the

relay safe and easy.

Local control of the relay can be carried out using a portable computer connected to

the front connector and remote control via the rear connector connected to the

distribution automation system through the serial interface and the fibre-optic bus.
March 16, 2026 BY
IN Honeywell

Honeywell PVB VAV Controller

Description

PVBxxxxAS-E is provided with more compact size and

accurate air flow measurement to meet the control of

the increasing demand for VAV terminals. It

communicates with BACnet MS/TP, fully compatible

with Niagara WEBs AX and WEBs N4 system.

PVBxxxxAS-E is a free programmable VAV controller,

assembled with a DP sensor for air-flow measurement

and a damper actuator for damper position adjustment.

Features

• Compact design to meet small enclosure

• Low air speed measureable by high accuracy DP sensor

• 5 Nm damper actuator, ease and stable to mount

with damper of VAVBox

• BACnet MS/TP communication between

controllers, up to 115. 2 kps

• Sylk™ Bus communication with wall module,

polarity insensitive wiring for both power supple

and communication

• Compatible with Niagara AX or N4

• Colorful and removable terminal blocks to simplify

wiring and replacement

• Qualified CE, UL, BTL

• BACnet qualified by BTL
March 16, 2026 BY
IN Honeywell

HONEYWELL EFFICIENCY AND SAFETY ON SITE

EFFICIENCY AND SAFETY ON SITE

• ISA/IEC 62443-4-2 Security Level 2 Certified Component supporting cyber security best practice

• Multi-color LEDs to show the operational status of the isolated RS-485 communications, HMI

device, Ethernet connection, and Service state of the controller.

• Built-in advanced diagnostics software facilitating troubleshooting for IP and MS/TP devices.

• Protective end covers to protect the touch flakes.

• Ferroelectric RAM (FRAM) to store the live data for the controller, including storing the last known

values when power is removed.

• UTF-8 and UCS-2 character encoding formats are supported.

• Ubuntu Core OS with snap container based modular software design (Cyber Secure).

• Supports 802.1x network authentication protocol as a Client (supplicant). Requires Niagara

N4.12 or later. Providing an IT standard security authentication method for network access.

• Processor featuring Neural Net Accelerator for future development of low latency AI/ML

algorithms at the Edge.

EASY UPGRADE

• All RS-485 ports support Panel Bus, BACnet™ MS/TP, Modbus RTU, and M-Bus.

• Removable terminal blocks with screw (factory installed) or Push-in terminals.

• Built-in Web server with HTML5 to support graphics.
March 16, 2026 BY
IN Honeywell

HONEYWELL OPTIMIZER ADVANCED CONTROLLER FEATURES AND HIGHLIGHTS

FEATURES AND HIGHLIGHTS

SIMPLE AND FLEXIBLE

ENGINEERING

• N-ADV-112-H, N-ADV-133-H, N-ADV 134-H controllers have multiple RS-485 ports and Ethernet ports – one isolated

IP port and multiple switched IP ports. Refer to the “Ordering Information” on page 2.

• N-ADV-133-H-BW series controller has three RS-485 ports and four Ethernet ports – one isolated IP port, three

switched IP ports with Bluetooth™, and Wi-Fi communication.

• RJ11 port to connect with an HMI device for field operations.

• Touch flakes to support RS-485 IO module devices.

• The multiple switched IP ports on the 133 & 134 models support both Daisy chain operation and RSTP

(Rapid Span Tree Protocol) which allows a fault tolerant network to be created.

• Built-in RSTP switch (Rapid Span Tree Protocol) allowing loop-free forwarding network topology.

• i.MX 8M Plus, quad Arm® Cortex®-A53 processor, long life industrial grade, Frequency: 1.2 GHz.

• Supports BACnet™/SC configuration within the Niagara Framework®.

• Conforms to BACnet™ Standard ANSI/ASHRAE 135 protocol version 1.15 (ISO 16484-5).
March 16, 2026 BY
IN Honeywell

HONEYWELL EFFICIENCY AND SAFETY ON SITE

EFFICIENCY AND SAFETY ON SITE

• ISA/IEC 62443-4-2 Security Level 2 Certified Component supporting cyber security best practice

• Multi-color LEDs to show the operational status of the isolated RS-485 communications, HMI

device, Ethernet connection, and Service state of the controller.

• Built-in advanced diagnostics software facilitating troubleshooting for IP and MS/TP devices.

• Protective end covers to protect the touch flakes.

• Ferroelectric RAM (FRAM) to store the live data for the controller, including storing the last known

values when power is removed.

• UTF-8 and UCS-2 character encoding formats are supported.

• Ubuntu Core OS with snap container based modular software design (Cyber Secure).

• Supports 802.1x network authentication protocol as a Client (supplicant). Requires Niagara

N4.12 or later. Providing an IT standard security authentication method for network access.

• Processor featuring Neural Net Accelerator for future development of low latency AI/ML

algorithms at the Edge.
March 16, 2026 BY
IN Honeywell

HONEYWELL OPTIMIZER ADVANCED CONTROLLER

The Advanced controllers are a family of next generation integration & plant controllers incorporating the Niagara

Framework® & powered by an IMX8 64bit quad-core processor. The Advanced controllers are freely programmable

IP devices, with a dedicated suite of IO modules providing extremely flexible control options. Using the power of

Niagara Framework® they provide both Ethernet & Serial integration options and are native profile BACnet™ Building

Controllers (“B-BC”). The Advanced controller is an ISA/IEC 62443-4-2 SL2 Certified Component device ensuring the

device supports cyber security best practice.

The N-ADV-133-H-BWA, N-ADV-133-H-BWE, N-ADV-133-H-BWW, N-ADV-133-H, N-ADV-134-H, and N-ADV

112-H Advanced controllers are designed for a wide variety of complex applications. These devices feature RS-485

ports for BACnet™ MS/TP, Panel Bus, Modbus RTU, M-Bus, and IO module devices, Ethernet ports for BACnet™

IP devices, and a RJ11 port interface for HMI devices. These controllers also have touch flakes to connect with

multiple IOs in series and a USB Type-C interface port to connect with a computer for serial communication. These

controllers can be mounted on either a DIN rail or on the wall in either horizontally or vertically orientations.
March 16, 2026 BY
IN Honeywell

HONEYWELL OPTIMIZER VAV CONTROLLER MOBILE APPLICATION

ACTUATOR

• Integrated 44 in-lbs. (5 Nm) actuator with 90 sec runtime at 60 Hz  (108 sec at

50 Hz) with analog position feedback.

PRESSURE SENSOR

• Field replaceable differential pressure sensor (± 500 Pa; span accuracy 3 % of reading).

MOBILE APPLICATION

Free to use mobile app for VAV balancing with easy access to the controller via

Bluetooth integrated in the controller.

• Easy pairing without the need to open the ceiling.

• Supports Android and iOS.

• Language support: English, French, Spanish, German, Italian.

• Wireless signal strength indication.

• Password protection

• Supports different types of balancing (min/max, set point).

• Command individual/group of VAVs, e.g., open a group of VAV dampers.

• Provides a report on balancing activities 

Menu

Search for products

Back to Top
Product has been added to your cart