Main specifications and technical parameters
- CThe working voltage and the output signal: working voltage: 15 ~ 28VDC
- Output signal: 4 ~ 20mA (second line)
- Ambient temperature: -30～+70℃
- Measuring range：0～300ms/cm
- Measurement accuracy：±1％FS
- Measured medium temperature：0～80℃
- Temperature influence：±0.03％FS
- Ex-mark: Ex mdIIBT6
- Explosion-proof certificate number: GYB 04679
The working principle and main structure of the product
By transmitting a constant amplitude and fixed frequency AC signal to the ring probe, for the liquid with different conductivity, the probe secondary will induce the same frequency signal of the corresponding amplitude, and the corresponding voltage signal will be obtained after the subsequent circuit processing. At the same time, the voltage signal corresponding to the real time temperature is taken. The standard conductivity values are compensated to 25 degree by function calculation. The value is displayed by LCD and converted to 4 to 20mA signal output at the same time. The principle block diagram is shown in Figure 3.1.
Fig. principle block diagram
Fig.3.2 Structure block diagram
Figure 3.2 shows，The left side of the diagram is the front view of the CNPS-8D08 digital conductivity sensor. The right side is the back view of the transmitter of the CNPS-8D08 digital conductivity sensor.
Installation and use：
Precautions for safety of explosion-proof：
- The product is equipped with earthing terminals, and users should reliably connect with them when they are using products.。
- With respect to cable frame site site operation of the staff and not easily smashed touch, damage, erection of safe and reliable principle。
- The installation and maintenance of the field must follow the warning words of “power failure and opening”.
- The outer diameter of the cable sheath is 8. The tightened nut should be tightened when the field is used, so that the inner diameter of the sealing ring is tightly clung to the outer diameter of the cable. The cable sheath of the seal ring should be replaced in time.
- There should be no harmful gas on the installation site for aluminum alloy. The shell of the transmitter is made of aluminum alloy, but because the water quality of the wellsite is often alkaline, it is still possible to produce a certain corrosion for a long time. It is suggested that the external protection measures should be strengthened to improve its life and reliability.
- the maintenance must be carried out in a safe place. When the installation site is confirmed that no flammable gas exists, it can be maintained.
- When the user installs and maintains the product, it must comply with the relevant regulations of the GB50058-92 “power device design specification for explosive and fire dangerous places” and GB3836.15-2000.
- The probe should prevent the generation of static electricity。
- The CNPS-8D08 digital conductivity sensor is installed in the mud tank. When installing, the pole will be placed vertically, and the slurry level is at least 5cm from the probe. The distance between the probe and the mud tank should also be guaranteed at least 5cm.
- when more than two SK-8D08 digital electrical conductivity sensors are installed in the same mud tank at the same time, they should be assured that their probe planes are located on one line and at least 5cm at a distance.
- The plug is connected to the CAN node. When the installation is in place, as shown in Figure 1.
Common fault and elimination method
|Fault||Causes and methods of exclusion|
|Display “OT_CR” on the screen||l Three reasons may cause the error to show that the temperature of the measured dielectric temperature exceeds the applicable temperature of the CNPS-8D08 conductivity sensor; the conductivity range of the mud conductivity exceeds the SK-8D08 conductivity sensor; the working temperature of the transmitter is overheated or overcooled.|
l CNPS-8D08 the temperature of the measured medium of the conductivity sensor is 10~80 degrees.
l CNPS-8D08 the conductivity of the conductivity medium is less than 300ms/cm.
l CNPS-8D08 the transmitter conductivity sensor temperature:－30℃～70℃。
|After displaying “R_J_C” or “A_J_C” on screen, press “key 1” can not carry out J calibration.||l The reason for the wrong indication is that the conductivity of the sample medium is too small.|
l The premise of J calibration is that the conductivity value of standard sample should be greater than 10ms/cm.
|Display “RTDC” on the screen, press “Key 1 “cannot be calibrated by RTD||l The reason for causing the wrong indication is that the temperature of the standard sample is too low.|
l The prerequisite for J calibration is that the temperature of standard mud should be greater than 3 degrees.
|Electrical conductivity shows instability||l Correct the sensor to the point where it is far away from the interference.|
|Electrical conductivity is incorrect||l Incorrect or inappropriate installation of the sensor。|
l The demarcation is incorrect and the calibration is re calibrated.。
|Other||Please consult the technical staff of our company.|
The standard length of the middle pipe of the SK-8D08 conductivity sensor is 2m, and the user can change the length of the intermediate pipe when ordering, according to the actual demand.