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maersk · Member 3 Joined: 17 Aug 2014 Posts: 891

Micro Automation: PI Controller with LOGO! for Simple Applications - Optimum Motor Speed Control (Set 23)
https://support.industry.siemens.com/cs/document/23753479/micro-automation%3A-pi-controller-with-logo !-for-simple-applications-optimum-motor-speed-control-%28set-23%29

In an injection molding plant, the molded parts are cooled down to a certain final temperature by a water cooling system. Several consumers are connected for cooling down up to three parts simultaneously.
To optimize the cooling performance and to restrânge failures, it is to be ensured that - independent from the number of active consumers, a constant pressure is always provided for the central feed. The adaptation of the pump flow rate, and therefore of the pressure, must be stepless.
It is to be ensured that the pump is only operated when sufficient cooling water is supplied. The current pressure (actual value) and the operating hours of the pump are to be displayed. It must be possible to edit the pressure needed by the consumers (setpoint value).

PI Controller with LOGO! for Simple Applications

The automation solution uses a LOGO! logic module with a connected SITRANS P pressure measuring transducer for capturing the current pressure in the cooling water cycle.
A PI controller in the LOGO! logic module adjusts the pressure by varying the motor speed depending on the pressure that is being measured. The pressure of the cooling water system is thus kept constant, independent from the number of consumers. The cooling performance is optimized and failures caused by a shortfall of pressure are prevented.

The asynchronous motor is connected to a SINAMICS V20 frequency converter, which receives the setpoint motor speed as a frequency setpoint via the analog output of the LOGO! expansion module AM2 AQ. The speed of the asynchronous motor is adjusted steplessly via the SINAMICS V20.

A SIRIUS wire electrode for level monitoring is connected to a SIRIUS monitoring relay. This is to ensure and monitor that the pump is supplied with fluid during operation. The monitoring status of the SIRIUS monitoring module is transmitted to a digital input of the LOGO! logic module.

The current pressure at the cooling water system, the setpoint pressure and the operating hours of the pump can be directly displayed on an external LOGO! TD. The setpoint value of the cooling water system can also be edited. On an integrated display of the LOGO! logic module, the setpoint pressure, the current pressure and the speed of the pump are displayed in a bar diagram.

PI Controller with LOGO! for Simple Applications

Four variants are available for downloading:
Software package for a real controlling with LOGO! 8
https://support.industry.siemens.com/cs/attachments/23753479/23753479_Set23_RegReal_DOKU_V24_en.pdf
https://support.industry.siemens.com/cs/attachments/23753479/23753479_Set23_RegReal_CODE_V24.zip

Software package for a controlling with LOGO! 8 and a simulation of the controlled system with S7-1200
https://support.industry.siemens.com/cs/attachments/23753479/23753479_Set23_RegSim_DOKU_V24_en.pdf
https://support.industry.siemens.com/cs/attachments/23753479/23753479_Set23_RegSim_CODE_V24.zip
Software package for a real controlling with LOGO! 7
https://support.industry.siemens.com/cs/attachments/23753479/23753479_set23_regreal_v23_en.pdf
https://support.industry.siemens.com/cs/attachments/23753479/23753479_set23_regreal_v23.zip

Software package for a controlling with LOGO! 7 and a simulation of the controlled system with S7-1200
https://support.industry.siemens.com/cs/attachments/23753479/23753479_set23_regsim_v23_en.pdf
https://support.industry.siemens.com/cs/attachments/23753479/23753479_set23_regsim_v23.zip

Documents
https://support.industry.siemens.com/cs/attachments/100761780/logo_system_manual_en-US_en-US.pdf
https://support.industry.siemens.com/cs/attachments/67267484/v20_operating_instructions_complete_en-US_en-US.pdf
https://support.industry.siemens.com/cs/attachments/68321612/v20_getting_started_400v__230v_en-US_en-US.pdf
https://support.industry.siemens.com/cs/attachments/54397927/manual_monitoring_relay_SIRIUS_monitoring_devices_en-US.pdf