Panasonic AFP7PSA1 User Manual

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Contents

Panasonic AFP7PSA1 User Manual Manual pdf 44 page image

4-12Installation and Wiring4.3 Safety Measures4.3.1 Safety Circuit Precautions regarding system design In certain applications, malfunction may occur for the following reasons:- Power on timing differences between the PLC system and input/output ormechanical power apparatus.- Response time lag when a momentary power drop occurs.- Abnormality in the PLC unit, external power supply, or other devices.In order to prevent a malfunction resulting in system shutdown take the following measures asadequate: Install the interlock circuit outside PLC When a motor clockwise/counter-clockwise operation is controlled, provide an interlockcircuit externally. Install the emergency stop circuit outside PLC Install an emergency stop circuit outside PLC to turn off power supply to the output device. Start up other devices before PLC The PLC should be started after booting the I/O device and mechanical power apparatus. When stopping the operation of PLC, have the input/output devices turned off after PLC hasstopped operating. Install safety measures in case of alarm outside the PLC body When an alarm is released, PLC output is turned off and its operation is stopped. In order toprevent a malfunction resulting in system shutdown under the above conditions, install safetymeasures outside PLC. Perform secure grounding When installing PLC next to devices that generate high voltages from switching, such asinverters, do not ground them together. Use an exclusive ground for each device whichshould be grounded at a grounding resistance of 100 Ω or less.4.3.2 Momentary Power DropOperation in the case of momentary power drop varies depending on the combination of units,the power supply voltage, and other factors. In some cases, operation may be the same asthat for a power supply reset. When a power supply unit (AC) is being used, operation is continued in the case ofmomentary power drop shorter than 10 ms. When 24V DC is being supplied to the CPU unit, operation is continued in the case ofmomentary power drop shorter than 4 ms.Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: info@clrwtr.com