Controller for management of processes
with weight measurement in a flow
(belt scales, flow meters)
Purpose:
The controller is intended to measure the material flow and control the related processes. Quantities measured by the controller are period and linear loading (based on the strain measurement). Default configurations for measurement and control, eligible to the user, cover almost all of the applications. The controller is situated on ‘Rittal-Schaltschranke Gmbh’ board AE1032, with dimensions 200/300/120 mm.
Configurations:
Basic configuration:
– input for load cells;
– input for tachometer (speed sensor);
– communication interface via RS232C or RS485 (based on preliminary customer request).
Additional module:
– analogue output 0-5V, 0-20mA or 4-20mA;
– 4 discrete inputs 24VDC;
– 4 relay discrete outputs.
Characteristics:
Power supply:
from 187 to 242V AC, 50 +/- 2Hz.
Temperature:
– working: from -5 to 40° C;
– storage temperature: from -20 to 50° C.
Class of protection: IP64.
Input for load cells:
– galvanic insulated (not less than 500 VDC / pic AC);
– ADC type: sigma-delta modulation, 18 bits resolution (262 144 units);
– range: up to 3.5 mV/V (sensitivity of the load cells);
– way of load cells connection: six-wired;
Temperature drift:
– zero drift: up to 3ppm/ °C;
– sensitivity drift: up to 1ppm/ °C.
Excitation Supplies:
– voltage: 5V AC p/p;
– current: up to 200mA (to 25 ohms equivalent resistance).
Tachometer input:
– Frequency range: from 1 to 1000Hz;
– Max. error: 0.005%;
– Power supply: from 5 to 15V DC (upon request). Consumption – up to 100mA;
Communication interface:
– RS232C or RS485 (upon request);
– Galvanic insulated (not less than 500VDC / pic AC);
– Baud rate – selectable from 0.6 to 57.6 kbits per second;
– Communication protocol – MODBUS ASCII (option – protocol with managing on the 9-th bit).
Analogue output (optional):
– 16 bits resolution;
– Accuracy: better than 0.05%;
– Selectable ranges: 0 – 5V, 0 – 20mA, 4 – 20 mA, 0 – 24 mA;
– Programmable range (weight for 100% of the range);
– Additional program setup of the off-set (partial) and the transmitting coefficient.
Discrete inputs (optional):
– 4 pcs. with fixed function depending on the selected program configuration;
– Input voltage of activation: from 12 to 30V DC;
– Consumed current: up to 10mA on 24V;
– Internal power supply of 24V DC unstable.
Discrete outputs (optional):
– 4 pcs. relay output type ‘normally open dry contact’ with fixed function;
– Commutated current – up to 0.5 A;
– Commutated voltage – up to 250V AC.
The analogue output, discrete inputs, and discrete outputs use common power supply for 24V unstable voltage with power 18W and have a combined negative pole (with a common mass). Altogether they are galvanically insulated from the other modules for voltage not less than 500VDC / pic AC.
Displays:
– LED display six-grade for showing the current value of the flow in t/h;
– 8 control LEDs with fixed function;
– LCD display with 2 rows, 16 characters each (Cyrillic alphabet) for showing the current status of the process, entering of major parameters, showing the archived data, etc.
Keyboard:
– Button for resetting;
– Button for temporary switching off/on the dosing process;
– Button for counter ‘with resetting’;
– Button for task specification (weight of a batch or value of supported flow at some dosing modes);
– Functional and digit buttons.
Functional Configurations:
Scale without dosing:
Scale with a tachometer:
– scale with speed measuring (belt);
– scale without speed measuring (inclined plane).
Scale without a tachometer:
– scale with speed measuring (belt);
– scale without speed measuring (inclined plane).
Dosimeter – first type:
A measuring device that controls the belt, but does not control the device feeding the material.
Dosimeter – second type:
A measuring device that controls the belt as well as the device feeding the material. In this case, the dosing process begins with the automatic reset of the scale and ends with an empty belt.
Dosimeter of a flow:
A measuring device that controls the belt and the device feeding the material aiming to provide the required flow. In this case, the analog output is used like an output of a PID regulator for belt speed control.
Archive data:
– Counters of total quantity of material passed – 2pcs.;
– Archives per 24-hour periods and shifts – for the last 40 24-hour periods;
– Archives per hour – for the last 72 hours;
– Archives per months – for the last 13 months;
– Archives for the last executed 40 dosing processes.