FX5U -80MT/ES not run under UPS

[Nugro 1]

Hello all,

Currently I'm using FX5U-80MT/ES; with power supply 100-240VAC, In my work place we're not using power grid, but using gensets. The problem came when there's power changeover from one genset  to other genset. FYI, gensets not run in synchronization.  I'm using UPS to keep power available for plc to keep ON.

But when running in UPS, PLC power is ON but not RUN. UPS no interruption, when power down min output from UPS is 230VAC, but PLC not in RUN state. Tested with several UPS same thing. Read on manual SM53 is to detect AC/DC Down. What it may possible cause PLC not in RUN state when I'm using UPS ? Thanks in advance. 

[pturmel 160]

What kind of UPS is this? (Brand/model)  Is it the type where the inverter continuously supplies the load?

[glavanov 40]

See if this helps...

[Nugro 1]

@pturmel, we use local brand UPS, Blue Gate UPS, Yes, it's supply to load up to 4 hrs, without power grid, when grid available automatically switched to grid.

@glvanov, thanks for the info, but main supply not less than 230VAC during switching. Will do another test. 

 

[Goran Vuckovic 15]

There is small chance that multimeter or most measuring devices will detect changes with duration of 10ms.

[pturmel 160]

4 hours ago, Nugro said:

when grid available automatically switched to grid

This is key.  It means the inverter does not support the load full-time.  With such switched UPS, there will always be a small glitch when the grid drops out before the UPS inverter turns on.  PLCs don't like that kind of glitch.  This kind of UPS typically has a small battery charger that will restore the battery slowly, then keep it topped up.

The other (more expensive) UPS design runs the inverter to the load all of the time.  With this kind of UPS, the grid connects just to the UPS' permanent battery charger, which must be large enough to simultaneously charge the battery and supply the inverter load.  When the inverter runs the load from the battery all of the time, there is no glitch when the grid drops out, because there's no switching (at all) on the load side.

Sounds like you have the wrong kind of UPS.  (Most brands have both kinds of designs in their product lines.)

For very large systems, consider getting the right kind of UPS just for the parts of your system that need it (like the PLC CPU).

[Nugro 1]

@Goran Vuckovic, yes it's true, can't see in that interval time

@pturmel, We're planning to install new industrial inverter than can support full load system.

@glavanov, I'm changing SD8008 to 100ms. Will see what can be happen in next power change.

 

BTW, thank all for your support and advice.