Proface AGP3500 - 10.4 DIO HMI" - Manual (Page 186)

Chapter 8 Installation and Wiring
8-15
8.2.5 Installation Precautions
External power failure or failure of the GP unit may cause abnormal behavior.
To prevent such abnormal behavior from leading to the abnormal operation of the entire system, and to ensure
fail-safe operation, configure circuits which may lead to machine damage or accident due to abnormal
operation (emergency stop circuit, protection circuit, interlock circuit, etc.) externally to the GP.
This section describes examples of the system circuit design to improve system reliability and to ensure
optimum performance.
„Fail-safe Design of the Electric Circuit
Design the electric circuit with consideration to equipment malfunctions caused when the GP is turned on by
a delay among the startup times of the control equipment connected to the GP output unit (especially the one
operated by a DC power supply), the GP unit itself, and the program. When remote I/O is used, create a
program that checks the status of the terminal with a logic program.
For example, connect voltage relay coils to the power supply circuit of the GP output unit and the power
supply circuit of the connected control equipment, and connect the contact to the GP input unit. Configure the
circuit to check the ON signal from the voltage relay in the logic program before executing the ladder of the
control equipment connected to the GP output unit.
„Rated Voltage
Be sure to supply an appropriate power supply voltage to your GP that is within the specified range.
„Power-down
All GP units except for AGP-3300
∗/AGP-3301∗ enter power-down status when an instantaneous power
interruption of the rated voltage continues for 20ms or longer.
AGP-3300
∗/AGP-3301∗ enters power-down status when an instantaneous power interruption of the rated
voltage continues for 10ms or longer.
When the GP unit enters power-down status, it stops the calculation even if the instruction is not finished.
For example, when the GP unit enters power-down status while 100 words of data are being transferred by an
FMOV instruction, the transfer stops midway.
Consequently, design your program with consideration to power-down occurrences.
• When you use the DIO/FLEX NETWORK board type unit of the GP3000 series,
read the following installation precautions.