IDEC MicroSmart Pentra - Manual (Page 41)

W EB S ERVER CPU M ODULE U SER ’ S M ANUAL FC9Y-B1278 3-13
3: I NSTALLATION AND W IRING
Power Supply
Power Supply Voltage
The allowable power voltage range for the slim type Web server CPU module is 20.4 to 26.4V DC.
Power failure detection voltage depends on the quantity of used input and output points. Basically, power failure is
detected when the power voltage drops below 20.4V DC, stopping operation to prevent malfunction.
A momentary power interruption for 10 ms or less is not recognized as a power failure at the rated voltage of 24V DC.
Inrush Current at Powerup
When the slim type CPU module, expansion interface module, or expansion interface slave module is powered up, an
inrush current of a maximum of 50A flows.
Power Supply Wiring
Use a stranded wire of UL1015 AWG22 or UL1007 AWG18 for power supply wiring. Make the power supply wiring as
short as possible.
Run the power supply wiring as far away as possible from motor lines.
For a power supply wiring example of expansion interface modules, see "Power Supply Wiring Example" of the basic
volume (page 2-77).
Grounding
To prevent electrical shocks, connect the terminal to a proper ground using a wire of UL1015 AWG22 or UL1007
AWG18. The grounding also prevents malfunctioning due to noise.
Do not connect the grounding wire in common with the grounding wire of motor equipment.
Separate the grounding wires of the Web server CPU module and external devices which can be a possible noise source.
Use a thick wire for grounding the Web server CPU module and make the grounding wire as short as possible to make
sure that noises from external devices can be conducted to the ground effectively.
• Use a power supply of the rated value. Use of a wrong power supply may cause fire hazard.
• The allowable power voltage range for the slim type Web server CPU module, expansion interface module
FC5A-EXM2, and expansion interface slave module FC5A-EXM1S is 20.4 to 26.4V DC. Do not use the Web
server CPU module on any other voltage.
• If the power voltage turns on or off very slowly, the Web server CPU module may run and stop repeatedly
or I/O operation may fluctuate at a voltage lower than the rated voltage.
• When Web server CPU module I/O signals are connected to a device which may cause a major accident in
case of an error, take a measure to secure safety, such as providing a voltage monitoring circuit outside the
Web server CPU module.
• Use one power supply to power the CPU module and the expansion interface module or expansion
interface slave module.
• When using a separate power supply, power up the expansion interface module or expansion interface
slave module first, followed by the CPU module, otherwise the CPU module causes an error and cannot
start and stop operation.
• Use an IEC 60127-approved fuse on the power line outside the Web server CPU module. This is required
when equipment containing the Web server CPU module is destined for Europe.
Caution