Controller input supply tolerance.

[alexfisher]

Hi, I’m about to power up my new UC300ETH-5LPT. I checked the supply (http://www.mouser.com/ds/2/468/R-78HBxx ... 958370.pdf) for my controller with a volt meter and it’s reading 5.18V unloaded. This is a little over the recommended 5V, I’m wondering if 5.18V (unloaded R-78HB5.0-0.5) is within UC00ETH-5LPT input tolerance or should I replace it? If replaced, can anyone suggest a suitable device?
Alex.

[cncdrive]

It is also a question that what is the tolerance of the tool you measured the voltage with?
I mean if you for example measured the voltage with a multimeter with a 1000Volts range then it can easily give you a 5% tolerance.
So, the first question is how real is the measured 5.18Volts, isn't it a measurement error only.

And the UC300ETH can accept upto 5.5Volts, and that is the absolute maximum for the TTL buffer chips which are directly connected to the 5V input Voltage.
If the voltage is higher than 5.5V then the buffer chips could damage.