The mixing container model consists of a tank with a motor-driven agitator M, in which two liquids are mixed together in a predetermined ratio and then heated to a set temperature. The two liquids are supplied via two feed lines, each of which has a coarse valve (V1.1 or V2.1) and a fine valve (V1.2 or V2.2) for exact dosing. The two flow rate sensors QI1 and QI2 generate pulses whose frequency is proportional to the respective filling speed; one pulse corresponds to just 1% of the container volume. The outflow of the mixture is controlled via valve V3. Two limit value transmitters (LIS1/LIS2) and an analog value transmitter (LI1) are available for measuring the fill level. The liquid in the tank can be heated via a heater H; a limit value sensor (TISmax) and an analog value sensor (TI1) are available to measure the temperature. The heater can be switched on both program-controlled and manually via button S2. If the temperature limit value is exceeded, this is signaled by the alarm light H1. The mixing process is started via the start button S1.
Input/output assignment
The inputs and outputs of the model are assigned as follows (The designation input or output refers to the connected control unit.
refers to the connected control unit):
Input no. Name TwinCat variable name Description
1 S1 I_S1 Start button (NO contact)
2 S2 I_S2 Switch on heating manual button (NO contact)
3 QI1 I_QI1 Pulses Flow rate sensor left inlet
4 QI2 I_QI2 Pulses flow rate sensor right inlet
5 TI1 I_TI1 Analog value transmitter temperature in degrees (100° = 27648)
6 TISmax I_TISmax Temperature limit value transmitter
7 LI1 I_LI1 Analog value transmitter level in % (100% = 27648)
8 LIS1 I_LIS1 Lower limit value transmitter level
9 LIS2 I_LIS2 Upper limit value transmitter level
Output no. Name TwinCat variable name Description
1 V1.1 O_V11 Coarse valve left inlet
2 V1.2 O_V12 Fine valve left inlet
3 V2.1 O_V21 Coarse valve right inlet
4 V2.2 O_V22 Fine valve right inlet
5 V3 O_V3 Outlet valve
6 H O_H Switch on heating
7 H1 O_H1 Alarm light
8 M O_M Agitator motor