數顯表

Principle of digital meter

Digital display instrument is a kind of analog to digital converters and variables to be measured values are displayed as decimal digital instruments, supporting it with a variety of sensors, the dispensers, you can display a variety of different parameters. Digital instrument with high precision, full function, the advantages of speed, strong anti-interference capacity, low power consumption, small size, intuitive readings, measuring results in digital form and can be fed into a computer, in order to achieve the production process automation.

Auxiliary power supply

Multifunction power meter with universal (AC/DC) power supply input interface, if you do not make a special statement, provide a 220V (AC/DC) or 110V (AC/DC) power connector standard products, instrument limits the working power supply voltage is AC/DC:80-270V, please ensure that the power supply is appropriate for the series, to prevent damage to the product.

A. AC power proposal in the line of fire are mounted on one side of 1 a fuse.

B. for electricity in areas with poor quality, recommended installing surge suppressors for lightning strike power circuit and electrical fast transient suppressors.

Input signal

Products using the calculation for each channel separately collected, ensure use identical, symmetric, with a variety of connection, suitable for different load forms.

Introductions:

A。 Input voltage: input voltage should be less than rated input voltage (100V or 400V), you should consider using the PT, voltage input required to install 1 a fuse.

B. current input: standard rated input current of 5 a, using external CT should be paid more than 5 a. If you are using on the CT is connected with other instruments, wiring threaded mode should be used, remove the product prior to the current input line, be sure to first disconnect the CT secondary circuit of circuit or shorted. Recommended terminal block, do not direct CT to facilitate disassembly.

C。 To ensure that corresponds to the input voltage, current, phase, direction; otherwise the numeric and symbol error occurs!! (Power and energy)

D。 Instruments enter network configuration based on the number of CT systems decisions, in the case of 2 CT, select three-phase three-wire components of two ways; in the case of 3 CT, select three-phase four-wire three-element method. Instrument wiring, instrument setting input Internet NET programming should be consistent with the measurement of the load wiring, or it will lead to an incorrect voltage or power meter. Three phase three wire, the voltage measurement and display of the line voltage, while in three-phase four-wire, voltage measurements show the phase voltages.

Use method

Measurement display

Multifunction power meter can measure the electricity in power grids parameters are: Ua and the Ub, and Uc (phase voltage); Uab, and Ubc, and Uea (line voltage) Ia, Ib, IC (current); Pa, Pb, PC, and Ps (total active power and active power per phase); Qa, Qb, QC, Qs (total reactive power and reactive power per phase); PFs (total power factor); Ss (total apparent power), FR (frequency) and active (reactive) electricity, all save the instrument and measurement of power parameters of power information sheet, digital communication interface can be accessed through instrumentation acquisition the data. For different types of instruments, which shows you how the content and may not be consistent, please refer to the specific instructions.

Display mode:

XS1 control word for the program can be set under normal conditions the displayed content, XS1=0 Automatic cycles, 1 (phase voltage), 2 (three-phase current), 3 (active power, reactive power, power factor), 4 (frequency), 5 (active energy), 6 (reactive energy).

Program operation

Under the program, instrument settings (SET), input (INPT), communications (CONN) three classes to enter the settings menu item, and using LED displays a hierarchical menu structure of management: 1th line LED displays the 1th floor menu information; 2nd row LED display 2nd level menu information, 3rd row LED to provide 3rd level menu information.

Programmatic manipulation of the four keys of the keyboard operation, namely: move left and right keys "←" and "→" menu or rolling back the "MENU" key, select OK "" to complete this operation.

MENU: in case of meter display, pressing the keyboard enter the programming mode, the instrument prompt for password: CODE, enter the correct password, the instrument can be programmed, set, instrument initial factory password is 0001; " MENU "side effect in the programming procedure, step. For example, in the programming mode, the INPT-I. SCL-5 press "MENU", instrument displays INPT-I.SCL.

"→" And "←" keys menu item switch move switch increase or decrease in size or number. For example, under the menu item INPT-T.U-0001 click the "→" becomes INPT-T.U-0002, press and hold the "→" and "←" onto the fast increasing/decreasing functions.

"" Select confirm and return to the previous menu.

In the case of programming mode returns to the measuring mode, the instrument prompts "SAVE-YES", select "MENU" does not save and exit, select "" save and exit.

Requirements: all instruments when used for the first time, check the meter's parameters required in the distribution system of the week parameter consistency. For example, AC380V, 200A/5A line you need to configure AC400V, 200A/5A appearance. Users also can be set according to the actual need to program the instrument again. Also a table for 400A/5A lines, simply the instrument of CT ratio "T.I" was changed to 80 will be able to. In the General case, behind the instrument tab of the table type of instrument parameters and factory-set parameters.

After the correct configuration of the instrument, in accordance with the actual requirements of the instrument is correct wiring, auxiliary power, input signal and output signal according to the instructions in the operating instructions.

Digital communications

RS485 communication connection

Serial asynchronous half provided RS458 communications interface, using MOD-BUS-RTU Protocol, a variety of data record card can be sent over a communications line. On one line can simultaneously connect up to 32 network power meter, each network power meter can set its address (Address No.), different series of different communication terminal number, traffic connections, you should use a shielded twisted-pair cable with copper wire mesh, wire diameter not less than 0.5mm. Wiring should be used when communication lines away from the strong electric cable or other environment of strong electric field, type of network connection is recommended, does not recommend the use of a star or other connection methods.

MODBUS/RTU communication protocol folding

MODBUS protocol used on a communication line and slave response mode communication connection. First, the main computer terminal equipment addressed to a unique address of signal (slave), and then, the Terminal response signal transmission in the opposite direction to the host, that is; in a separate communication line signal along the opposite transfer all communications traffic in both directions (half-duplex working mode).

MODBUS Protocol is allowed only in the host (PC,PLC) and communication between terminals, but independent data exchange between devices is not allowed, so that the terminal equipment does not occupy the communication line when they initialize, and limited response to the native query signals.

Host queries: queries message includes device address code, function codes, data information code and calibration code. Address code showed that to selected of from machine equipment; function code told of was selected of from equipment to implementation what function, for example function code 03 or 04 is requirements from equipment read registers and returns they of content; data paragraph contains has from equipment to implementation function of other additional information, as in read command in the, data paragraph of additional information has from what registers began read of left-device number; check code used to test a frame information of correctness, for from equipment provides has a validation message content whether right of method, CRC16 calibration.

Response: If the device produces a normal response in response to messages from the machine address code, a facility code, data coding and CRC16 checksum. Information codes range from data collected by the device: If a register value or status. If there are errors, we are to be from the machine does not respond.

Transmission is a separate set of data within the data frame structure, limited rules for the transmission of data, defined below,-RTU transfer mode compatible with MODBUS Protocol. Of bits per byte: one start bit, 8 data bits, (parity bit), one stop bit (parity bit) or 2 stop bits (no parity bit).

Data frame structure, namely: message format.

Address code

Function code

Data code

Well-tested code

1 BYTE

1 BYTE

N-BYTE

2 BYTE

Address code in the frame of the first part, consisting of a byte (8-bit binary code), decimal 0~255, use only 1~247 in our system, and other reserved. These bits indicate a user-specified device address, the device will receive data from a connected host. The address must be unique for each terminal, was addressed only to the Terminal response contains the address of the query. When the Terminal sends a response back, told host response from the machine in the address data which Terminal communicates with it.

Function output

Energy measurement and pulse output

Provides energy metering, 2-way electric energy pulse output function and RS485 digital interface to power data is displayed and far Eastone. Instrument 3 row 12 bit LED achieved active is can (are to), and no work power (perceptual) 1 times side data of displayed, right figure in the said are to active power data =369587.28kWh (degrees); set electric level open of light coupling following electrical of power pulse (resistance signal) achieved active power (are to) and no work power (reverse) far biography, used remote of computer terminal, and PLC, and DI switch collection module collection instrument of pulse total to achieved power cumulative measurement. Hugh output with the output or power for precision testing of way (national measurement procedures: standard table comparison of pulse error method).

Electrical characteristics

Collector switch Iz ≤ VCC ≤ 48V voltage, current 50mA.

Pulse constant

3200imp/kWh the fastest Pulse less than 200mS. Its meaning is: cumulative 1kWh pulse output when the meter number n (3200) to emphasize that the 2 times of 1kWh of electricity power data, PT, CT case, 1 corresponds to the n pulse data power 1kWhx voltage ratio PTx current transformation ratio CT.

Matters needing attention

1, before using the meter must be powered on for 15 minutes.

2, avoid vibrations or shock, do not use where there is excessive dust, corrosive gas.

3, input wire should not be too long, such as the signal to be measured input is long try using twisted-pair shielded cable.

4, if the signal is superimposed with high-frequency interference, try low-frequency filters in the online.

5, long term storage when not in use, please power on not less than 4 hours at a time every three months.

6, it should be preserved for a long time to avoid direct light, should be stored at ambient temperature-25 ° C~55 ° c.

7, such as meter not show, you should check the auxiliary power supply, the voltage is in the range.

8, such as the link doesn't work, check the input signal and signal terminals are tightened.

9, unless the PT has enough power, or PT signals cannot be used as auxiliary power, to ensure that the instrument work properly.

10, CT in the loop current terminal screws must be tightened, ensure a reliable contact inlet/outlet, in order to avoid failures.

11, to check the instrument, verify the instrument shall be better than 0.1 level, to ensure the calibration accuracy.