Measurement and control block GDC-701

Control block GDC-701

GDC-701 is a stand-alone ventil bags filling and control block. These bags are widely used lately for dry construction materials. Filling principle is based on engine screw - a motor (one- or three phase) is pushing a big screw, which pushes out the material through a pipe. On this pipe there is ventil bag. To have correct dosing two main things has to be accomplished - weigh measurement of the bag and control of motor revolutions. GDC-701 has three main modules:

  • motor revolution control module
  • weight measurement module, receiving signal from load cell
  • main module, controlling the other two, processing the information, receipts set up and other parameters

user manual

Main technical parameters of GDC-701

power supply 220 VAC +10/-15%, 50Hz +2/-2Hz
power consumption < 1,2 kW (motor 1,1 кW)
weight measurement capacity up to 3000 divisions
division value according to client requirements
serial interface RS-232C, 9600, 8, N, 1
relay outputs 2 - alarm and end of dosing
work temperature from -10° C to +40° C
dimensions (H/W/D) 350/400/150 mm
own weight 9 kg

General information

Revolutions control module regulates work power of AC motor, using phase shift. This control method is not so sophisticated as frequency regulation, but is easier to be build and has enough accuracy for the purpose. The idea is when certain weight has been filled in the bag, main control module to reduce motor revolutions, that way making fine dosing and achieving needed total bag weight precision. Of course, frequency motor regulation can be added, but this reflects on the price of GDC-701, especially when three phase asynchronous motor is used. Base motor is one phase asynchronous with nominal power 1,1kW/1400n-1. When ordered, this can be different or frequency control can be added.

Weight measuring module is receiving signal from load cell to determine current weight of the bag. This load cell is crucial to be mounted on the right position. With period of 400ms this module sends information to the main module and according to that information motor revolutions are controlled. Other commands are also implemented for correct machine work. Load cell with sensitivity of 2 mV/V or 3 mV/V can be mounted.

Main module interface to the user is LCD screen 4x40 and 4-button keyboard for interaction and set-up. Several main parameters for the dosing process can (and must) be defined - first weight, final weight, motor revolutions when first weight is present (in percents full motor power), motor revolutions between first and total weight (again in percents full power), time when bag's weight is checked, permissible tolerance of total weight, cycles count, after that 'zero' command to weight module must take place. Total of 12 presets can be memorized, can be more when ordered or needed. In the moment main module can read weight measurement data up to 3000 divisions and 500gr division value max.(look EN 45501:2001). Additional option is to send dosing data to personal computer through serial RS-232/RS-485 interface. There are also two really outputs - alarm and dose end signals.

Normal mode of operation