Title: +038=360.000-OU045T_03-PCD2.m4160 PLS SBC - Hardware Manual.pdf
and the header of the DB takes up a further three bytes We recommend always using DBs with addresses ≥ 4000. These can hold more elements (16384 instead of 384), take up less space (only 4 bytes instead of 8 bytes per element, but NB, 8 bytes instead of 3 for the header) and the access time is substantially shorter.Example of manual partitioning:Hardware Manual for the PCD2.M5 Series│Document 26/856; Version EN 09│2012-01-253-30Saia-Burgess Controls Ltd.PCD2.M5_ Classic CPUs and expansion housingsData storage in case of power failure3.11 Data storage in case of power failureThe resources (registers, flags, timers, counters etc), and possibly the user program and the text strings/DBs, are stored in RAM. To ensure that they are not lost and that the hardware clock (where present) continues to run when there is a power failure, the PCD2s are equipped with a buffer capacitor (SuperCap) or a buffer battery:CPU typePCD2.M5_BufferRenata CR 2032 lithium batteryBuffer time1...3 years1)