Setra Blog

Until recently, there was no standard industry network protocol for building automation, and users had to choose between many different systems from different manufacturers. Proprietary communications were a result of no off-the shelf communication solution.

Today, we have reached a place where there are three inter-operable standard network protocols to choose from: BACnet, LonWorks and Modbus. All three are widely used, and according to a Building Operating Management survey in 2011, 62% of respondents had at least one BACnet application; for LonWorks the percentage was 40%, while for Modbus the number was 30%.

User-side energy submetering is becoming increasingly popular in new commercial construction and renovation projects alike. The latest advanced LEED certification requires operator-owned submeters to be installed in high consumption areas and facilitate continuous tracking of total consumption for an entire structure.

Imagine a tone being played by two musical instruments -  let’s say middle C (261.63 Hz). While the pitch played on a piano may be the same as on an electric guitar, its timbre is very different. The sound wave generated from a piano or a simple synthesizer is relatively simple and clean, but the sound wave coming from an electric guitar is often very distorted for effect and contains natural harmonic overtones.

Understanding specific job requirements, such as performance, installation, amperage load and environmental factors is critical to selecting the proper current transformer for an application. Conventional current transformers (CTs) come with their limitations as they are difficult to install and are lacking in performance and measurement range. Rogowski coils have significant advantages with regards to installation, cost and performance.

The Internet of Things (IoT) is changing the way people run their homes. More and more devices are becoming available to consumers that allow them to automate their thermostats and regulate their power consumption, often-times controlling these systems from the phone in their pocket. Products like the Nest thermostat and the Sense home energy monitor provide homeowners convenient tools that also help save utility costs.

Building Automation

In commercial and industrial buildings, there are similar (albeit far more robust) systems and protocols used for the same purposes called building automation. Building automation is the automatic and centralized control of a building’s heating, ventilation, air conditioning, security, electrical, and other systems through a Building Automation System (BAS).

Looking at your electric bill can be a daunting task. There are many factors that can affect your bill’s total — factors that are only amplified in large commercial and industrial sites.

One such consideration is peak demand. Peak demand is the largest instance of power usage in a given time frame, typically a rolling fifteen minute window. Measured in kilowatts (kW), peak demand is different than consumption. Total consumption  is measured in kilowatt hours (kWh) over a given period of time (e.g. monthly, quarterly, etc.). 

Power factor is a measure of how effectively electrical power is being used. It is defined as the ratio of real power (the power that actually performs work, measured in watts) to apparent power (the total power supplied to the circuit, measured in volt-amperes).

The power flowing through an alternating current (AC) load isn’t always pulling its full weight. Every AC circuit has some degree of non-working power as part of its total power reading and this can affect the amount of power a system is truly drawing.

A Cyclic Redundancy Check (CRC) error is an error-detecting code used to identify accidental changes to raw data in digital networks and storage devices.

Cyclic Redundancy Check (CRC) Error indicates when data is corrupted. Calculating from all data, CRC validates packets of information sent by devices and verifies it against the data extracted, ensuring its accuracy. When sending packets over, BACnet automatically calculates and stores a CRC value for the packet. Later when the packet is received, BACnet calculates the CRC value of the packet and compares it to the original value. If the two values do not exactly match a CRC error occurs.

We didn’t say it was easy monitoring energy. While monitoring energy consumption, it may be overwhelming to manage numerous appliances using a power meter. To keep management simple, you can measure several different circuits by placing multiple current transformers within a single channel. However, this can only be done if all circuits are powered from the same phase of electrical circuits. This method is useful to combine all circuits into one measurement, oversee all appliances or to measure energy used for lighting. By placing multiple (2+) light circuits in a single current transformer (CT) you can capture more light circuits with bundled inputs. The maximum amount of CT’s per channel is limited to the gauge of the wire to fit in the terminal block. Placing multiple CT’s per channel has both its advantages and disadvantages:

The baud rate is the rate at which information is transferred in a communication channel. Baud rate is commonly used when discussing electronics that use serial communication. In the serial port context, "9600 baud" means that the serial port is capable of transferring a maximum of 9600 bits per second.