Load cell wiring method – ifm

There are four-wire and six-wire load cells. Four-wire system: EXC EXC: Power cord, that is, the DC power supply supplied by the instrument to the sensor. SIG, SIG-: The signal line, that is, the signal line output by the sensor, is output to the instrument. In addition to the above four lines, there are more than two four-wire systems: SEN, SEN-: feedback line, that is, the sensor feeds back the voltage value received by practice to the scale. In addition, both 4-wire and 6-wire sensors have shielded wires: when the distance between the load cell and the scale is close, the line voltage loss is very small, and the SHIELD 4-wire system is used. The application of the six-wire system in long-distance measurement has strong anti-interference ability and accurate measurement. In general, weighing instruments are compatible with four- and six-wire sensors.

Load cell wiring method – ifm

However, when connecting a four-wire sensor, a wire is used to short-circuit the EXC and the sensor, and the EXC and the sensor at the end of the weighing instrument are short-circuited. (Wiring diagram of the four systems of the sensor)/The connection between the load cell and the instrument/The connection between a single sensor and the instrument only needs to be connected one by one according to the wire number and the instrument terminal. There are two ways to connect two or more sensors to the instrument:

1。 The sensor wires of the sensor junction box are connected in the junction box and then connected to the instrument via the main cable.

2. Connect a main cable directly in parallel from the instrument, and all sensors in the field are connected in parallel to the cable. After introducing sensors and instruments, let's share how to judge the quality of sensors. First of all, it is necessary to know under what conditions the sensor is good or bad. There are two points:

1。 The components shown by the instrument are inconsistent with the practical ones, and they vary greatly. When we use the standard component to check the accuracy of the scale, if we find that the component displayed by the instrument is very different from the component of the scale, and the zero point and measurement range of the scale cannot be changed, then we should consider whether the sensor is damaged. In practice, we have encountered such a situation: a package table says that the package amount of a package of feed is 20KG (the amount can be set according to the demand), but when the electronic scale is used to check the package amount, it is either more or less, and the policy amount of 20KG is very different.

2. The alarm code "OL" appears in the instrument. This code indicates being overweight. If the meter reports the code frequently, you need to see if the sensor is damaged. /How to tell if a sensor is good or bad/1. Measuring Resistance (Instrument Power Down) (1) If there is a sensor specification, it will be much simpler. First, measure the input and output resistance of the sensor with a multimeter and compare it with the instructions. When the difference is big, it breaks. (2) If there is no indication, measure the input resistance, that is, the resistance between EXC and EXC-; output resistance, i.e., the resistance between SIG and SIG-; Bridge resistance, i.e. revolt between EXC vs. Sig, EXC vs. Sig, EXC vs. Sig, and EXC vs. Sig. The input resistance, output resistance and bridge resistance should be satisfied with the following relationship: "1", the input resistance> the output resistance> the bridge resistance "2", the bridge resistance is equal or flat in pairs.

2. To measure the voltage (the instrument is energized), the first thing to measure is the voltage value between the instrument terminal EXC and EXC with the DC voltage level of the multimeter. This is the excitation voltage of the sensor, which contains DC5V and DC10V. Here let's take DC5V as an example. The output sensitivity of the sensor we are exposed to is generally 2 mV/V, that is, the linear relationship between the output signal of the sensor corresponding to the output of 2 mV for every 1V excitation voltage. When there is no load, use the millivolt of the multimeter to measure the millivolt number between the SIG and the SIG line, if it is about 1-2mv, the description is correct; If the number of MVs is very large, the sensor is damaged. When loading, the mv file of the multimeter is used to measure the number of mv between the SIG and the SIG-line, which will be added in shares according to the components loaded, and the maximum value is about 5V (excitation voltage) * 2 mv/V (sensitivity) = 10mV. Otherwise, the sensor is damaged. 1. Do not over-range often, which will cause irreversible damage to the elastomer and strain gauge inside the sensor.

2. Electric welding operation (1) disconnect the signal cable from the weighing display controller;

(2) It is necessary to set the grounding wire of the electric welding near the welding part, and the sensor shall not become a part of the electric welding circuit. 3. Insulation of the sensor cableThe insulation of the sensor is selected at 20M, and the measurement value should be infinity. Otherwise, the sensor is damaged.

Load cell wiring method – ifm

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