XWGJ Series Circular Chart Automatic Balance Recorder

The XW (Q) GJ series instruments are accompanied by certain transmitters, which can be widely used in enterprises such as textile, food, environmental protection, chemical, mining, metallurgy, petroleum, power generation, and scientific research units to automatically measure, indicate, and record the measured parameters.
The XW (Q) GJ series instrument is a potential difference meter that can be used in conjunction with various standard calibrated thermocouples and radiation temperature sensors to measure temperature. It can also be paired with corresponding transmitters that generate DC potential to measure various physical or mechanical quantities.
The XW (Q) GJ series instrument is a balanced bridge, which is compatible with various standard graduated resistance thermometers and can also be used in conjunction with other transmitters that produce changes in resistance values.

Characteristics of XWGJ Series Circular Chart Automatic Balance Recorder
Compact structure, small volume, and light weight.
Single pen continuous recording, with the recording paper replaced every 24 hours for easy maintenance and repair.
The scale length of the instrument ruler is 550mm, with high indication resolution. Long distance observation is very clear.
Strong anti-interference performance.

3、 Working principle
（1） The XWGJ series instruments use voltage compensation (balance) method to measure the measured parameters
The measured (electromotive force signal ET) is input into the measurement circuit of the instrument through a filtering unit. Due to the fact that the measured potential and the unbalanced potential generated by the measurement circuit are connected in reverse phase, when the two are of different sizes, a difference potential is generated after comparison. This potential is amplified by an amplifier and drives the balance motor. The balance motor drives the sliding arm to contact the sliding line resistor in the measurement bridge through gear transmission, changing the contact position between the sliding arm and the sliding line resistor, that is, changing the output unbalanced potential of the measurement bridge. The balanced motor drives and the sliding arm moves accordingly until the unbalanced potential generated by the measuring bridge reaches equilibrium with the measured signal potential (i.e. the difference potential is 0). At this point, the amplifier has no marked input, and there is no power output. The balanced motor stops rotating, and the sliding arm of the instrument pointer, recording pen, and sliding wire resistor are linked on the same axis. When the motor is balanced, the position indicated by the pointer on the ruler and the position recorded on the paper by the recording pen simulate the numerical value of the measured signal.
The XWGJ series instruments that are paired with thermocouples, according to the measurement principle of thermocouples, determine the magnitude of their thermoelectric potential based on the temperature difference between their potential and cold ends. Therefore, when the temperature of the hot end remains constant, the measured potential must be automatically compensated for as the temperature of the cold end changes with the ambient temperature of the instrument (the thermocouple cold end is connected to the instrument terminal block). The cold end compensation method used in this instrument is to replace R2 in the library with a cold end compensation resistor RW made of a resistance material (copper wire) with a positive temperature coefficient in the measurement bridge circuit（ Manganese copper resistor is used in the bridge circuit to compensate for the variation in thermoelectric potential caused by changes in cold junction temperature. This resistor is placed on the same terminal block as the cold junction of the thermocouple (i.e. at the same temperature as the cold junction). If the hot temperature remains constant and the cold junction temperature rises, the thermoelectric potential value decreases. At the same time, the compensating resistor also increases in resistance value due to temperature rise. The voltage drop across this resistor also increases, and the increased voltage drop compensates for the decreased thermoelectric potential, thus achieving automatic compensation for the cold junction temperature.
（2） XQGJ series instruments
The thermistor (resistance thermometer RT) is a bridge arm of the instrument measurement circuit. When the measurement circuit is in a balanced state, the output of the diagonal of the bridge is the other. When the resistance of RT changes due to temperature changes, the bridge can lose balance and output an unbalanced voltage on the diagonal of the bridge. After amplification by an amplifier, it drives the reversible motor, drives the sliding arm of the sliding line resistor, and drives the pointer and recording pen until the instrument bridge reaches balance, indicating and recording the measured parameter.

4、 Technical indicators
Basic indication error: ± 0.5%
Record basic error: ± 1%
Return difference: 0.25%
Power consumption: 40W
Scale length: 550mm
Effective width of recording paper: 87.5mm
Power supply: AC220V 50Hz
Working environment conditions: temperature 0~50 ℃, relative humidity 10%~90%
Weight: ＜ 14Kg


Product Introduction: