How to wire the pressure sensor? Attached wiring diagram

Pressure sensors generally come in two-wire, three-wire, four-wire, and some even five-wire systems.

The two-wire system of the pressure sensor is relatively simple. Most customers know how to wire it. One wire is connected to the positive pole of the power supply, and the other wire, which is the signal wire, is connected to the negative pole of the power supply through the instrument. This is the simplest. The three-wire system of the pressure sensor is on two wires. The wire system adds a wire. This wire is directly connected to the negative pole of the power supply, which is a little more troublesome than the two-wire system.



A four-wire pressure sensor must have two power input terminals and the other two are signal output terminals. Most of the four-wire systems have voltage output instead of 4~20mA output. The 4~20mA ones are called pressure transmitters, and most of them are made of two-wire systems.

Some of the signal outputs of pressure sensors are not amplified, and the full-scale output is only tens of millivolts. Some pressure sensors have an internal amplification circuit, and the full-scale output is 0~2V.

As for how to connect the display instrument, it depends on the measuring range of the instrument. If there is a gear suitable for the output signal, it can be measured directly. Otherwise, a signal adjustment circuit must be added. The five-wire pressure sensor is not much different from the four-wire pressure sensor, and there are relatively few five-wire sensors on the market.

Pressure sensor attachment cable physical diagram






Pressure sensor installation points
1. Turn on the monitor before connecting the pressure sensor system.
2. Use disinfection measures to open the package and confirm that all interface safety seals and three-way valves and other accessories are in good working condition.
NOTE: When connecting connectors, do not overtighten.
3. All ports of the stopcock should be covered with protective caps with holes. The protective caps should not be replaced with non-porous protective caps until the sensor system is filled with heparin saline solution and all air bubbles are exhausted.
4. Connect the pressure sensor to the monitor and set the monitor to zero according to the monitor instructions.
Notice:
① If the zero adjustment cannot be performed, please replace the sensor and reset it to zero;if the zero adjustment is unsuccessful, please check whether the cable connection, monitor, etc. are normal.
② When installing DPT-248Ⅱ and CH-DPT-248Ⅲ sensors, color coding should be used to identify blood pressure types: red---arterial pressure;blue---central venous pressure;yellow---pulmonary artery pressure;green-- -Left coronary artery pressure;white---others.
5. Flush the pipeline with heparin saline and remove the air in the pipeline.
Note: There should be no air bubbles remaining in the pipeline.
6. After all pipelines are filled with heparin saline, connect the sensor system to the human body.

Unavoidable errors in pressure sensors
1. Offset error
Since the vertical offset of the pressure sensor remains constant throughout the pressure range, changes in transducer dispersion and laser trim corrections will produce offset errors.
2. Sensitivity error
The size of the error is proportional to the pressure. If the device is more sensitive than typical, the sensitivity error will be an increasing function of pressure. If the sensitivity is lower than typical, then the sensitivity error will be a decreasing function of pressure. This error arises from changes in the diffusion process.
3. Linear error
This is a factor that has a small impact on the initial error of the pressure sensor. The error is caused by the physical nonlinearity of the silicon, but for sensors with amplifiers, the nonlinearity of the amplifier should also be included. The linear error curve can be a concave or convex curve.
4. Hysteresis error
In most cases, the hysteresis error of a pressure sensor is completely negligible because of the high mechanical stiffness of the silicon wafer. Hysteresis error generally only needs to be considered in situations where pressure changes are large.