Introduction of Digital Electric Isolation Sensors

Digital electrical sensors are designed for digital measurements of DC/AC parameters of DC systems, single-phase, 3-phase 3-wire and 3-phase 4-wire systems. These sensors can be used to measure single parameter (voltage or current) and multi-parameters. For AC systems the measurands are, voltage Ua, Ub and Uc, current Ia, Ib and Ic, frequency F, active power P, reactive power Q, power factor cosφ, active energy, reactive energy, power Pa, Pb and Pc. 

Digital output communication interface is RS-485 or RS-232C optionally. The communication is ASCII format or MODBUS protocol. The DC sensors are of double isolation. It means that the output of the sensor is electrically isolated from its input. The AC sensors are of treble isolation, which means that the input, output and power source of the sensor are isolated each others. The isolation voltage is up to 2500V/1 min. The sensors provide reliable and stable performance with its MTBF more than 30000 hours. Also it combines many attractive features including high accuracy, easy to program, small size, easy to install, less power consumption, and wide operation temperature etc. 

These digital electrical parameter sensors can be applied in many industrial automatic control systems and equipments to measure, monitor and control their operation. 

1. General specifications

2. Definition of Part Numbers

The part number definition is in conformity with national standard GB7666-87 of the P. R. China. . Main Code

When you select a part number according to above mentioned definition, please specify the measuring range (span) you require. 

Typical Example 1:

CYAJ12-12BS3-0.5/110V*5A: 1 single-phase AC multi-parameter Digital Electrical Sensor; treble isolation; output: ASCII format, RS-485 interface; power source: +12V; aperture: Ř6.5mm; Case style: S3; accuracy: 0.5%; measuring range: voltage: 0~110V, current: 0~5A.

Typical Example 2:

CYAJ42-34MN-0.5/380V*5A: 3-phase 4-wire AC multi-parameter digital electrical Sensor; treble isolation; output: MODBUS protocol, RS-485 interface; power source: +24V; no aperture (input connection through terminals); Case style: N; accuracy: 0.5%; measuring range: voltage: AC 0~380V, current: AC 0~5A.
 

A digital electrical parameter sensor is able to communicate with all kinds of master equipments (computers) by appropriate connection. The connecting method: connect pin “DATA+” of CY485A (RS-232/RS-485) converter of the master equipment together with the pins “DATA+” of all sensors, connect the pin “DATA–” of that of master equipment together with pins “DATA–” of all sensors, and put resistance terminators (120Ω) at two ends of the bus (it is not necessary when the distance is ≤1200m). Then connect to the power
source. The measurements can work with running application software of the sensor in the master equipment. The sensors can be connected directly with the master equipment, which has a RS-485 interface.

4.2 Application and Programming

The digital electrical isolation sensors can easily measure many kinds of useful electrical parameters of 3- phase 4-wire, 3-phase 3-wire and single phase and DC power circuits and systems. They can be widely used in various industrial control and measuring systems. One multi-parameter digital sensor can supersede many kinds of single parameter sensors, i.e. current, voltage, frequency, power, and energy sensors etc. They can reduce the cost of system and are easy to wire at work site; especially their advanced isolation technology greatly improves the system performances and helps to provide higher system reliability and stability. These sensors are able to connect to any industrial digital control system with the RS-485 bus communication technology, ASCII and MODBUS command set. So they are convenient to program and to extend the system and let you build up your own control system easily.

Default configuration: sensor address is set to “01” (hex), and baudrate is 9600bps.

Note:

1. Sensor address is programmable. It can be set from 0 through 255(00-FFH) optionally.
2. There are 5 programmable baudrates: 1200bps, 2400bps, 4800bps, 9600bps and 19200 bps.
3. The configuration data will be stored in EEPROM after the sensor address and baudrate were revised.

4.2.1 Measuring Range

The measuring range is: voltage 0~500V, current 1~25A. Usually 1.2 times of the maximum value of measuring range can be measured correctly. If it is necessary, you can use an external current transformer to transform heavy current into a standard input for these sensors.

The sensor could not be damaged when the inputs are less than 2 times of the maximum value of the measuring range of voltage or 10 times of the maximum value of the measuring range of current. Please pay attention to the connection of the polarity of power supply correctly with right rated voltage.

4.2.2 Configuration

Each digital sensor must be configured before it is connected to a network. The baudrate of sensor must conform to that of the network. Any address collision, i.e., overlapping the address of any other device in the network is not allowed. To configure a sensor with case S3 you need RS-485/RS-232C converter, master equipment with RS-232 interface and application software of the digital sensor. The configuration can be completed easily by our digital sensor application software. You can also configure it by programming according to the command set of the digital sensor.

4.2.3 Data Acquisition

After having connected the sensor correctly, the sensor will return (respond) the measured data to the master equipment when it sends one of read data commands to the sensor. The data inside the EEPROM of the digital sensor will be refreshed every 100ms. The measured data of energy is accumulated since powered-on and is cleared after received a clear command.