, )-Product Overview
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: r, series liquid level display controller, consists of two parts: display and control instrument and sensor. The measured medium is conductive and non-conductive liquids such as water, oil, acid, alkali, industrial sewage, etc. It is widely used in automatic control systems in petrochemical power stations, metallurgy, light industry, pharmaceuticals, paper, food, water plants, sewage treatment and other fields. It mainly measures and remotely controls the media in a variety of open and closed containers and underground pools. It can also Monitor and display alarms in the central control room or instrument console.
: r , ) Two technical characteristics
, , : ) Primary sensor
: Composed of float detection tube flange and junction box (see picture)
: Measuring range: Type, type.
: cannot be smaller than.
: Working temperature: Type: ℃ ~ ℃, Type: ℃ ~ ℃, if the temperature is higher than the above, it needs to be customized.
: Working pressure: type:, type:, type normal pressure. When it is greater than the above value, it can be customized.
: Density of the measured medium/.
: Viscosity of the measured medium ().
: The detection tube is generally made of stainless steel (r) or polytetrafluoroethylene (or) for anti-corrosion applications.
: The float ball is made of stainless steel (r) ball and is used in anti-corrosion situations with a protective layer of polytetrafluoroethylene (or). The diameter of the plastic float is , and the diameter of the float is .
: < )Secondary display meter
: According to the on-site control accuracy and liquid level control range, various instruments with different numbers of control points can be selected. If accurate display control is required, continuous display of liquid level is selected. Control table, if there are no special requirements, the instrument accuracy can reach level 1. Various forms of display and control meters can provide upper and lower limit alarm signals, normal liquid level display and external output relay control signals (a pair of normally open and normally closed contacts). There are two types of display tables: vertical and horizontal. Tutu is the panel type of the display table.
: Display mode
, , : ① ~ type, dot matrix display.
: ② It is a digital continuous display or a digital continuous display plus a light bar for synchronous display.
: The upper and lower limits of the liquid level display and control instrument, three models of instruments, are achieved by adjusting the height of the sensor control point. Type meter is realized by adjusting the upper and lower limit liquid level setting switches on the display and control panel. type, completed by adjusting the slide key on the panel. type, achieved by adjusting the touch keys on the panel.
: Ambient temperature and humidity: Ambient temperature: ~℃ relative humidity%.
: Upper and lower limit output contact capacities: For non-inductive loads and large contact capacities, intermediate relays can be used.
: Working power supply %, alarm mode: sound and light alarm.
: Overall dimensions of the secondary instrument, internal thread interface of the sensor. Instrument weight:.
: ) Local display table
:
Display mode: the same as the display control table. Working power:, provided by the display control meter.
:
Ambient temperature and humidity: Temperature: ~℃. Relative humidity%.
: ) Three working principles
: The sensor of the series liquid level display controller is installed vertically in the liquid to be measured. Under the action of the buoyancy of the liquid, the float with a magnetic steel inside changes with the liquid level. and produce displacement. The magnetic field of the magnet acts on the wet (dry) reed switch in the sensor detection tube, causing its contacts to close or disconnect, resulting in a change in the sensor output resistance. The change in resistance is converted into the corresponding light-emitting diode lighting up and off through the display meter, thereby simulating the change in the level of the measured liquid. When the liquid level is between the two wet (dry) reed tubes, it does not pull in, and the display meter remains The previous position until the next wet (dry) reed pipe moves to ensure that there is no dark area.
: The liquid level alarm point is preset. When the liquid level reaches the predetermined set point, the relay in the display meter will act. Through the on and off of the relay contacts, the corresponding upper and lower limit alarm signals and output control will be given. signal to realize automation of liquid level display and control.
: ) Four installation and wiring
) Sensor installation
: The sensor can be installed by bypass pipe installation method, pool wall installation method and container top installation method (see picture). When the sensor is installed on the container, its lower part should be firmly fixed on the bottom of the container. (See the figure and Table 1 for details of the pool wall installation method)
: Fill the space between the sensor's detection tube and the mounting flange with packing, and then tighten it with a compression nut.
: During installation, one end of the floating ball fixed magnetic steel must be facing down, otherwise measurement errors will occur. Before installation, iron nails and other ferromagnetic substances can be used to test and judge.
: )Display meter installation
: The display meter embedded panel is installed on the instrument panel, and the opening size is ++.
: )5 Debugging and Maintenance
: Before installing the instrument, the sensor and display control instrument should be tested first. The specific operations are as follows:
: Measure the continuity between the sensor lead wire terminals Condition.
: ① ~ type, when the float moves from bottom to top and passes through each measurement and control point, use a multimeter to measure between the common end and the terminal, from off to short-term on respectively. (~type, the empty leg end remains unchanged).
: ③ / type, when the float moves slowly from bottom to top, use a multimeter (preferably digital) between the terminals and the resistance reading can be measured in a step-like manner. Changes are normal. If the float moves upward and the reading stays on a certain number, it means that the reed switch at a certain point (section) is broken. Either the glass shell of the reed switch is broken, or the reed switch body has cracks, causing Internal contacts shorted. At this time, unscrew the sensor junction box, loosen the fixing screws, carefully remove the internal core, and replace the damaged reed switch.
: If the installed sensor is not used for a long time, or the float stays at a certain water level for too long, the magnetic field of the float magnet acts on the reed switch at the same height for a long time to weakly magnetize the float. When passing through this place again, it does not release after being attracted, and the display indicates a certain position. At this time, the reed switch should be replaced. Care must be taken during inspection, because the weakly magnetized reed switch is easy to recover after vibration and is difficult to confirm.
: If the sensor is normal, start checking the secondary display meter. After connecting to the AC power supply, the green indicator on the front panel
: The light is on, indicating that the power supply is working normally.
: For the ~ type liquid level display controller, you only need to short-circuit the wiring terminals on the back of the instrument to the dots with wires to make the corresponding diodes in the normal liquid level display window on the front panel light up. If the alarm point has been preset, when it is lower than the lower limit alarm point (or higher than the upper limit alarm point), an audible and visual alarm will sound, and the corresponding relay will act.
: For / type liquid level display controller, there should be left and right DC voltage between the rear wiring terminals of the instrument and the One light, which is normal due to induction electricity) turns into all lights, while the upper and lower alarm diodes change from light at the bottom to light at the top, then turn off at the bottom and light at the top, which is normal. If there is no change in the continuous light-emitting diodes or the situation is opposite to the above, it is likely that the integrated block is damaged and must be replaced immediately.
: If there is no change in the alarm LED, it may be that the diode is damaged or the triode used for control is damaged. At the same time, carefully check whether the internal wiring of the instrument is broken and whether the components are desoldered or have incorrect solder joints. Pick up and wait.
: When an abnormality occurs in the liquid level measurement and control system, you should first determine whether the fault occurs on the sensor or in the display controller (secondary display meter). When checking, you must disconnect the secondary instrument and the primary sensor. with a connection between them.
: Under the premise that the instrument and sensor are normal and the wiring is correct, turn on the power and push the float, the display points will change continuously. When the float moves from bottom to top, the display points will continue from bottom to top. When the floating ball moves from top to bottom, the display points should go out in sequence from top to bottom. The entire process does not produce flickering or dark areas. If during the movement, two adjacent light points appear to be connected, light up or go out at the same time, you should pull out the instrument movement and adjust the internal potentiometer until they are separated.
: Generally, the controller has been debugged before leaving the factory. The user only needs to complete the external wiring and operation according to the actual situation.
: )6 Ordering Instructions
: Indicate the model, specifications and required quantity of the display controller.
: Indicate the sensor material, working medium, working pressure, working temperature, and whether to install a flange.
: Indicate the sensor size: ? ? ? Whether you want an over-limit alarm.
: Special specifications can be negotiated separately.
: Design requirements for the instrument panel, selection of indicator light colors, and whether the meter needs to be displayed locally? Can be selected by the user.
: Ordering example: For example, the liquid level display controller required by the customer must meet the following conditions, that is, its measurement principle is magnetic immersion type, used in drainage situations, its display mode is a four-point display throughout, and the primary sensor material It is polytetrafluoroethylene, the sensor length is meters, the liquid level display uses a red indicator light, ℃ explosion-proof type, requires an audible and visual alarm when the upper limit is exceeded, the medium is alkaline wastewater, equipped with a local display meter (the indicator light is red), the quantity is one set . Then the model he chooses should be B.
DXYK-3 liquid level controller supplied by Dingxing