PMP-165 (Modbus) level sensor
Application
Designed to control up to 14 leveols of tank infil. Sensor transmits the measured data via digital interface and may be used in automatic control and alarmin systems:
- - Overfill protection;
- - automatic level support;
- - Minimal level control (pump “idle” work prevention);
- - Double wall tanks interstitial tightness control;
- - purification systems tank level control;
- - Premises flooding control; и др.
PMP-165 is equipped with galvanically released interface RS-485. Current liquid level data is transmitted by controller via Modbus protocol with RTU format in accordance with «Modbus application protocol specification v1.1b».
Design, principle of operation
<
p> The metal rod with reed switches (in correspondence with measured levels quantity) is placed inside the guide pipe. Board are connected serially with two wires, forming a variable resistor with resistance determined by the liquid level. When liquid level is minimal (all floats lay down the stoppers), the resistor circuit provide maximal resistance. When the liquid level rises, the floats alternatively rise and close the terminals of reed switches that shunt the resistors, thus, the total circuit resistance is decreased. The signal is converted to a digital signal by controller and then transmitted via RS-485 interface Modbus protocol. Control levels value adjustment, is executed by moving of reed switched and their stoppers along the rod. The quantity of control levels might also be altered.
The terminal clamps «2» on PMP-165 board are designed for connection of the board with reed switches, terminal clamps «3» are used for connection of sensor to power line, terminal clamps «4» are used for connection of level sensor via RS-485 interface.
Switch 5 is designed for reset to default settings. The following parameters shall be reset: Modbus address, data transfer speed, pairity mode. Switch 6 locks the possibility of these parameters altering. Terminals «1» are used as additional contacts (see. OM).
Technical parameters
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