2 posts in this topic

Hello all,

My understanding is that the FX3 and iQ-F Series PLCs don't require a battery. Program memory and device data is retained in EEPROM. The Q Series on the other hand requires a battery to retain program memory and device data. Is that correct? What about the iQ-R series? Does it require a battery?


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Actually, in the case of FX3, if you use FX3U with no optional Flash memory card installed, FX3U-32BL battery still is required to keep the program. If we talk about FX3S and FX3G, yes, the battery is not required to keep the program as it is kept by EEPROM. Even though, it is important to mention that FX3G may require battery depending on how you use and save R file registers (you have two ways to keep R file registers data, one is saving them to an EEPROM area called ER file registers area by using RWERP instruction; the second option is to install an optional FX3U-32BL and set "Use battery" in FX3G parameters) and to keep file register and the RTC working with CPU power down.

In case of iQ-F it is a little bit different: Program is kept in EEPROM memory and the latch/retentive memory up to 12k works is kept in an embedded FeROM (or FROM) memory, a memory with technology that allows keeping data without battery but, unlikely EEPROMs, it has rewriting life similar to a RAM memory!

In the case of QPLC it is possible to save a backup program in Standard ROM embedded memory and do a boot every time the QPLC is restarted, so you don't necessarily need the battery in QPLC for keeping the program, besides the factory setting is using the battery to keep the program in the CPU memory. In the case of retentive/latch registers, you still need a battery to keep data when CPU power is down.

In the case of iQ-R, the program is stored in an EEPROM type but the latch/retentive registers depend on the battery, as well as the RTC. The battery used by iQ-R CPUs may be the same as the QPLC or FX3 (FX3U-32BL) depending on the CPU model.



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