UPS battery voltage indicator. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Power Supplies

 Comments on the article

The author suggests installing a microcontroller battery voltage indicator in the Masterguard A1000 uninterruptible power supply.

In the Masterguard A1000 uninterruptible power supply (UPS), after the warranty period of the battery has expired, a warning about the need to replace it automatically turns on - the battery voltage threshold indicator flashes and an audible signal sounds periodically. In this mode, the regular battery voltage level indicator does not perform its functions. This phenomenon is also observed after independent replacement of batteries with new ones. Of course, this can be fixed by contacting a service center, where they will replace the batteries and reset the warning signals, or if the appropriate software is available, then the user can do all this on his own. But if for some reason there are no such opportunities, you can use the method described below.

To solve this problem, a device is proposed, which is a stepped battery voltage indicator and a logic analyzer of the UPS operation mode. The device allows you to restore the function of indicating the voltage on the battery and the supply of sound signals with minimal intervention in the design of the UPS. The voltage indicator is assembled on the PIC12F675-I / P MK, it contains everything necessary for organizing such an indicator - an ADC, outputs that allow you to directly control the LEDs, and the ability to work from an internal clock generator. The UPS operating mode analyzer is made on the logical elements of the K561LA7 microcircuit and is responsible for generating warning sound signals.

The scheme of the device is shown in fig. 1. The device receives +5 V power directly from the UPS control board. On the DD2 chip, an indicator of the voltage level on the battery is assembled. The resistors R1 and R3 are used to divide the input voltage taken from the storage battery, which consists of three batteries connected in series with a nominal voltage of 12 V and a capacity of 7,2 Ah. Using this divider, the voltage on the battery (36 V) is brought into line with the allowable values ​​for the MK. Pin 5 of the microcontroller DD2 is programmatically configured as an ADC input, and pins 2, 3, 6 and 7 are configured as outputs. The latter are connected to the threshold voltage indicator LEDs, which, together with quenching resistors, are installed on the UPS control board and are designed as a column of five indicators on the front control panel.

Rice. 1. Diagram of the device (click to enlarge)

Due to the lack of the required number of pins for the applied MK, one LED is not used, it shines constantly - its cathode is connected to the negative line of the device. The remaining LEDs turn on depending on the voltage at the top output of the resistor R1 according to the circuit. So, the second LED turns on when the battery voltage reaches 33 V (minimum value), the third - 36 V, the fourth - 37,8 V, the fifth - 41,4 V. The last value corresponds to the state of full charge of each battery (3x13,8 = 41,4 .XNUMX V). Thus, a luminous column of five LEDs of the voltage indicator allows us to consider that the UPS battery is in a charged state.

The calculation of the coefficients entered into the memory of the MK is given in the table. It is assumed that the voltage of one fully charged battery is 13,8 V, fully discharged - 11 V, intermediate values ​​are chosen arbitrarily. The coefficients are calculated from the condition that the input voltage of the ADC MK 5 V corresponds to a value of 1024.

Table

As mentioned above, an analyzer of the UPS operation mode is assembled on the logic elements of the DD1 chip, it is responsible for giving sound signals.

The inputs of the DD1.1 element are connected to the cathode of the "Emergency" LED of the UPS, which is controlled by applying a low level to the cathode. In the normal state, the "Emergency" LED does not light, there is a high level on its cathode and on the DD1.1 inputs. If an emergency occurs in the UPS, the "Emergency" LED turns on, a low level appears at the inputs of the DD1.1 element. Accordingly, a single signal appears at its output, which is fed to the input of GP3 DD2 and switches all four LEDs connected to the outputs of the MK into a flashing mode. The voltage meter LEDs turn on and off at half a second intervals. The same single signal passes through the open diode VD1 and the limiting resistor R2 to the base of the transistor VT1 and opens it, which will trigger the relay K1. Its closed contacts supply power to the UPS buzzer - a continuous beep sounds. After the emergency is eliminated, the "Emergency" LED will turn off. The voltage indicator on MK DD2 will return to the UPS battery voltage measurement mode, relay K1 will open the power supply circuit of the sound emitter. If this circuit is left open in the normal state of the UPS, the buzzer will emit periodic beeps.

The lower input of the DD1.2 element according to the scheme is connected to the cathode of the "Bypass" LED (Bypass), it is also controlled by a low level supply. In the normal state, the "Bypass" LED also does not shine, there is a high level on its cathode and on pin 6 of the DD1.2 element. At the top input DD1.2 according to the scheme, there is also a single signal, therefore, a low level will be set at its output. If you turn on the "Bypass" mode, at pin 6 of the DD1.2 element, the high level will change to a low level, and a high level will appear at its output, which, as in the first case, will trigger the K1 relay and connect the UPS sound emitter. The emitter will emit sound signals, the voltage indicator mode will remain the same - there will be a measurement and indication of the voltage on the battery. After deactivating the "Bypass" mode, the corresponding LED will turn off, the audible signals will stop.

The inputs of the element DD1.3 are connected to the cathode of the "Network" LED of the UPS. In the normal state, when the input mains voltage is present, the LED is on, and there is a low level at the inputs of this element. There is also a zero signal at the output of element DD1.4 - relay K1 is de-energized, the battery voltage indicator is working. In the event of a power failure in the network, the UPS will switch to battery power, the "Network" LED will turn off. A single signal will appear at the output of the DD1.4 element, which will turn on relay K1 and, through closed contacts, will supply power to the sound emitter, the sound signal will turn on. The indicator will show the voltage level on the UPS battery. After the appearance of mains voltage, the UPS will switch to mains power, the battery charging mode and the "Network" LED will turn on. Relay K1 will turn off. The voltage indicator will show the voltage level on the battery in charging mode.

The battery voltage indicator with the UPS operation mode analyzer circuits is mounted on a 43x43 mm breadboard. The relay RES55A is used in the device, passport RS4.569.607. The PIC12F675-I/P microcontroller operates under the control of a program stored in its non-volatile memory. The program was developed and compiled in the "MikroBasic PRO for PIC V3.2" environment, the latest version of which can be downloaded from the mikroe.com website and used with a demo license, since the program code does not exceed 2 kb.

As a drawback of the proposed device, it should be noted that there is no sound signal after switching on the UPS battery condition test mode.

Before carrying out work, it is necessary to disconnect all external suitable cables from the UPS, remove the U-shaped cover and dismantle the batteries. The UPS control panel is fixed to the front cover and can be removed by unscrewing four screws inside the case. The prototyping board with the device mounted is connected by conductors to the points on the UPS control panel indicated in the diagram. The designations in the diagram correspond to the inscriptions on the UPS control panel on the part side. All conductors shown on the left in the diagram are soldered to the indicated points. But the conductors shown in the diagram on the right have features at the connection points. After connecting the outputs of the MK to the points of the UPS control panel, it is necessary to cut the printed conductors coming from these points. You can also connect the cathode of the LD511 LED to pin 10 of the U502 chip. If this connection is not made, the LD511 LED (lower in the battery voltage indicator) will constantly blink. After making the above connections, the control panel is fixed in its place in the front cover, and the device board is fixed nearby, in the free section, using hot glue. The appearance of the resulting structure is shown in Fig. 2.

Rice. 2. Appearance of the structure

Then the relay contacts are connected in series with the sound emitter located on the upper elongated UPS board. To do this, carefully cut the printed conductor on top of the board between the capacitor C35 and the sound emitter BZ1, and the wires from the relay are soldered from the bottom of the board to the positive terminal of the capacitor C35 and the output of the sound emitter closest to C35. It remains to connect the conductor coming from the divider R1R3 of the device to the positive terminal of the UPS battery. This can be done at the point of connection of the positive battery terminal to the main board at the 30 A fuse. To do this, the conductor from the device is stripped of insulation at a distance of 10 mm and clamped into the positive cable connector from the battery (red wire). Then replace the front cover, install and connect the batteries, close the U-shaped cover - the UPS is ready for operation.

The program and firmware of the microcontroller can be downloaded from ftp://ftp.radio.ru/pub/2015/08/meter_bat.zip.

Author: M. Tkachuk

See other articles Section Power Supplies.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive Sharks are less likely to attack people 15.02.2019 In 2018, 66 unprovoked shark attacks on humans were recorded worldwide, the lowest since 2008, when 55 attacks were recorded. Another 34 attacks last year were human-instigated, nine shark attacks on boats, and one attack on a diver in a public aquarium. In terms of geography, 32 of the 66 unprovoked attacks in 2018 took place off the coast of the United States (half of them in Florida), another 20 in Australia, three each in Brazil and Egypt, two in South Africa, one each in Bahamas, Galapagos Islands, Costa Rica, New Caledonia, New Zealand and Thailand. More than half of the victims (53%) were involved in surfing and related sports during the attack, 11% were diving, and another 30% were just swimming. On average, over the past ten years, shark incidents have killed six people a year worldwide. The Florida Museum of Natural History has kept shark attack statistics in the International Shark Attack File for over 60 years. Over time, the number of attacks continues to grow. So, until the end of the 1980s, the number of attacks in a decade never exceeded 300, and during the 2010s it already exceeded 700. The peak year was 2015, when sharks attacked people for no apparent reason 98 times.

Other interesting news:

▪ Thermal curtains

▪ Intel Expands Support for Hyper-Threading Technology

▪ Smart ballpoint pen for handwriting digitization

▪ The fastest supercomputers in the world

▪ Logitech G CLOUD Gaming Handheld Console

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the website Electrotechnical materials. Article selection

▪ article Karataev, Karataevshchina. Popular expression

▪ article When did the English language appear? Detailed answer

▪ article Upholsterer. Standard instruction on labor protection

▪ article Electronic voltage regulator for a motorist. Encyclopedia of radio electronics and electrical engineering

▪ article Jump card. Focus Secret

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024