Lighthouse PLCs, Inc. : Automation Forum
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Hopefully the information presented here will help provide solutions to some of today's automation challenges. Some issues are probably old, some are probably new. Many are products of the economy, the resultant reduction in manpower, exacerbated by aging equipment crippled by decreases in maintenance budgets. The ULTIMATE goal here is that we all become more successful in our careers and chosen professions.
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The Hitachi EMII series has three different types of memory modules. They are:
MPM-2R: 2k word EPROM
MPM-1E: 1k word EEPROM
MPM-2E: 2/4k word EEPROM
After the initial writing, the EPROM will not allow further programming, program modifications, changes, etc. Exposure to a U/V source will “wipe” the chip, allowing it to be reprogrammed. The way you describe the problem, leads me to believe you may have EPROM memory.
THE MPM-1E and MPM-2E are EEPROM, which do allow for multiple writing (just like RAM). The MPM-1E provides 1k (970) words. the MPM-2E provides 2k words of memory when used in the CPM-E and CPM-E2 processors. When the MPM-2E is used in the CPM-E3 processor, 4k (3,997) words can be addressed.
I hope this helps with your project.
