Omron NX Series Hardware User Manual page 25

• When you insert a flat-blade screwdriver into a release hole on a screwless clamping terminal block,
press it down with a force of 30N or less. Applying excessive force may damage the terminal block.
• Do not incline or twist the flat-blade screwdriver while it is in a release hole on a screwless clamping
terminal block. Doing so may break the terminal block.
Power Supply Design
• Select an external power supply with sufficient capacity by considering the power supply capacity or
inrush current when the power is turned ON that is specified in this manual.
Otherwise, the external power supply may not be turned ON or malfunction due to unstable power
supply voltage.
• Use all Units within the I/O power supply ranges that are given in the specifications.
• Do not apply voltages that exceed the rated value to any Input Unit.
• Do not apply voltages or connect loads to the Output Units or slaves in excess of their ratings.
• Surge current occurs when the power supply is turned ON. When selecting fuses or breakers for
external circuits, consider the above precaution and allow sufficient margin in shut-off performance.
Refer to this manual for surge current specifications.
• If the full dielectric strength voltage is applied or turned OFF using the switch on the tester, the gen-
erated impulse voltage may damage the Power Supply Unit. Use the adjustment on the tester to
gradually increase and decrease the voltage.
• Install external breakers and take other safety measures against short-circuiting and overcurrents in
external wiring.
Turning ON the Power Supply
• It takes a certain time for startup to enter RUN mode after the power supply is turned ON, depend-
ing on the type and configuration of the Unit and its settings.
During startup, the outputs for NX Units on the CPU Rack will be OFF. Note that the outputs on the
slaves will behave according to the setting values.
Therefore, use the system-defined variables and the device variables for each Unit in the user pro-
gram to confirm that startup processing and I/O data communications are established before at-
tempting control operations.
NX-series NX502 CPU Unit Hardware User's Manual (W629)
Precautions for Safe Use
23