Model 10BHDM384 Expanded Hisotry Memory Card
allows a total system volatile "history" memory of 416K readings or a total nonvolatile (battery-backed) "history" memory of 384K readings. Note that a complete set of data records will typically take more than one "reading," depending on the number of channels and bit groups in the set and also the inclusion of system DATE in the output. Installation of the 10BHDM384 requires a special "history backplane" within the mainframe.
When you use the 10BHDM384 simply to extend the RAM memory of your system's Model 10BDR64 History Card, the History Card's original 32K scaled readings—plus the 384K additional readings stored on the 10BHDM384—will remain volatile, and will thus be lost upon loss of system primary power.
When, however, you use the 10BHDM384 to furnish battery backup for the entire system history memory, then the History Card's original 32K memory is no longer available to the system. In this case, you must apply a NONVOLATILE HISTORY (NVH) command, whereupon all current history memory will be completely cleared, and all subsequent data recordings will be stored in nonvolatile memory on the 10BHDM384 Card only.
In addition to its statistical analysis functions, the Model 10BSPC384 High Density History SPC Option Card also provides the function of a Model 10BHDM384.