Earlier, in a series of blogs on eStorm-B1 BLE module, we have discussed about few applications of the module such as smart metering, as a Bluetooth to serial adapter along with a demo of the same. Further to a very positive response to the module, Embien has come up with an Evaluation Kit for the same. Incorporating various features targeting different market segments, we have designed the EVK as a ready to use product. This blog will introduce the reader to the kit for eStorm-B1 BLE module and in detail its application as a BLE to RS232 MODBUS converter

RS232 Modbus serial interface 

RS232 serial interface is still one of the most used wired communication standards. Introduced in 1960, it has survived and still surviving onslaught from many advanced standards because of its reliability and simplicity. They are intended to operate over a distance up to 15 meters and the maximum data rate is around 160 Kbits per second. They are often being used in many applications such as data acquisition systems, PLCs etc. While the underlying logical layer can be handled by UART interface, there are many possible application layer protocols that can be run on it. One of the most popular industrial protocol standards is called Modbus.

Modbus is a serial communication protocol developed for transmitting information over serial lines between electronic devices. The Modbus network can have one Master device and up to 247 slave devices. The master device can request or write the information to the slave and the slave device will supply the information. Registers are allocated for each data in the slave device and the master will write or read data to and from a slave device’s register.

It is an open protocol, where the manufacturer can build into their equipment without any royalties. The protocol has multiple versions such as Modbus RTU, Modbus ASCII for serial communication and Modbus TCP for Ethernet. Modbus has become the standard communication protocol in industry and it is a commonly available means of connecting industrial electronic devices.

Need for Wireless Communication 

Day by day, the communication interfaces and protocols are being updated to handle large data more reliably and over a longer distance. Of late, due to the advent of Industry 4.0 and IIoT, the need for wireless communication becomes inevitable. Industry 4.0 brings smartness in automation and data exchange in manufacturing technologies. It includes IoT, cloud computing, etc which calls for seamless data communication. Existing infrastructure can enable them with minimal changes using wireless technologies. This necessitates a suitable gateway for converting the wired serial interfaces to wireless.

Embien, following the current industry trends has launched a wireless module “eStorm-B1” under its eStorm series of solutions. The BLE module can support wireless serial communication with the available UART interface and can readily be used as a BLE to UART converter bridge. In addition to the COTS BLE module, Embien has also launched an evaluation kit “eStorm-B1 EVK”. This evaluation kit can support quick evaluation of eStorm-B1 module features.

Following are the features of eStorm-B1 EVK,

  1. 1X RS232 or RS485 serial interface
  2. 1X CAN interface
  3. 1X LIN interface
  4. One analog input and one isolated digital input for external sensor interface
  5. One digital output for external load control
  6. Onboard EEPROM
  7. Onboard Accelerometer
  8. Battery operated with inbuilt battery charger
  9. Compact dimension with mounting holes
  10. Screw type PCB connectors for serial and CAN interface enabling rigid connection to external devices
Evaluation kit for eStorm-B1 BLE module

Evaluation Kit for eStorm-B1 BLE Module

eStorm-B1 EVK as Wireless Modbus gateway

Of various interfaces, one that interests us for this blog is the presence of a RS232 interface. eStorm-B1 EVK based BLE to RS232 Modbus converter is suited for wireless Modbus gateway applications discussed earlier. eStorm-B1 EVK supports three wire RS232 serial communication via null modem cable and is exposed via a screw type PCB Terminal connector. Designed for rugged industrial environments, the EVK can operate in 5V DC input and RS232 receiver can accept up to +/- 30V input withstanding surges up to 15-kV (HBM) in the RS232 lines. Optional enclosure is also available.

On the protocol front, it includes a fully tested Modbus Client stack. It can query Modbus slaves present in the line. Android application is also available that can be used to configure the device and acquire data. Some of the features supported by the eStorm-B1 EVK based Wireless Modbus Gateway are,

  • Configuration of baud rate, Stop and data bits.
  • Modbus RTC/ASCII support
  • Continuous data acquisition
  • Notification based on change of value
  • Customizable buttons in the App for simple configuration of Modbus slaves

Thus eStorm-B1 as a wireless Modbus gateway can be used to interface with multiple devices for applications such as wireless data acquisition via existing data acquisition device, controlling the machines via PLCs for various industrial automation application, etc.

About Embien

Embien Technologies is a leading provider of embedded design services for the industrial automation. We have done various types of Data acquisition Systems, Industrial Human Machine interfaces, BLE based pH Meters, precision measuring instruments etc. We are currently working on enabling the industry 4.0 initiatives to make them smarter and greener.

Smart Metering

Today things are made smart and processes are becoming smart which enhances the life style of humans in many ways. One such example is the “Smart Metering”. All over the world, the mechanical energy meters are replaced by digital energy meters and currently advanced to smart meters which provide accurate results for greater period of time.

Digital energy meter is an electronic device that measures and stores the consumption of electric energy periodically and communicates the stored information to the provider (utility) via wired communication (Optical port, serial communication) as well as wirelessly for monitoring, analysis and billing. The wireless energy meters are referred as Smart Meters and most commonly used in industrial segments for various reasons and low end energy meters (wired communication) are used in domestic, commercial segments which supports digital interface such as RS232, RS485 serial communication.

Advanced Metering Infrastructure

Since the smart meters include wireless communication such as GSM/GPRS, low power radio, etc the readings can be updated in the central database from anywhere in the world and facilitates the customer (User) with plenty of information’s such as daily usage, peak demand, last interval demand, load profile, voltage profile, sag and swell events, phase information, power factor, tamper notifications, etc. This type of system is named as “Advanced Metering Infrastructure“(AMI). Such a huge amount of information is more important in building a smart grid by which the amount of power generation can be predicted based on power demands.

Automatic Meter Reading

Smart meters with AMI system are more advanced and expensive which makes them overrated for domestic segments. Similar to the “Advanced Metering Infrastructure” (AMI), Automatic Meter Reading (AMR) system is available as an automated way to collect basic meter reading from low end energy meters that are widely used in domestic segments where a system is required for collection only. AMR includes a handheld reading entry device where data from Smart Meters is acquired by connecting the device to the digital ports typically RS232 or RS485 serial ports using dedicated serial cables. The technician will have to plug these cables to the meter of concern and the handheld device will acquire the readings automatically. Likewise the technician will acquire data from each and every meter of his zone and the acquired readings are transferred to the central database for billing.

Though AMR has become common way of reading meters, it can be made more advanced. At present there are many wireless technologies available for small data transfer at very low costs. Among the various wireless technologies, BLE is the most popular. With the BLE enabled smart phones together with an Android app will simply replace the handheld AMR system which performs the similar functionality with wireless operation. Also a tiny BLE module with serial interface (RS232) like eStorm-B1 is sufficient to enable wireless connectivity for the energy meters.

Smart Metering using eStorm-B1 BLE Module

In previous blog, we have discussed in detail about eStorm-B1 BLE module application as a UART to BLE Bridge with a brief demo video. In this blog, we will demonstrate a Smart Metering application which can be realized by interfacing eStorm-B1 with energy meter via RS232 interface and by replacing the traditional handheld reading device with Smart AMR Android app running in Android smart phone with BLE connectivity.

The following video shows the demo of Smart Metering application,

In this demo, a digital energy meter is upgraded to a smart meter by adding eStrom-B1, an NXP KW31Z based BLE module via already available RS232 serial interface. In the other end, an Android Smart phone is equipped with a custom designed Android application “SMART AMR” which will communicate with the smart meter via BLE connectivity and acquire the reading when required.

The following are the features of Smart AMR Android application,

  1. Secured login – User name and password protection for authorized person login only
  2. Area selection – User configurable settings for selecting region, circle and section of his/her zone
  3. GPS based location mapping – Automatic mapping of the user’s present location
  4. One touch reading acquisition – Complete list of available registered meters in the particular location with complete details such as consumer name, ID, meter number, phase, load information and one touch acquisition of old, new reading and energy consumption.
  5. Auto update – Automatic update of acquired readings to central database via available 3G/4G connectivity in Smartphone.

This type of setup is very much suitable for AMR systems which can replace the handheld systems with the low cost smart phones and can reduce the burden on technicians by reducing more physical works that are present in the current handheld systems.

About Embien: Embien Technologies is a leading provider of embedded design services for the Semi-conductor, Industrial, Consumer and Health Care segments. Embien has successfully executed many projects like based on IoT such as healthcare Wearables, Gateways, and Data Analytics etc. Embien also offers a set of wearable design collections complete with electronics, firmware and Cloud that can be used to shorten product development costs and time significantly.