eWON General Reference Guide - Esco Drives & Automation

General Reference GuideIO Servers Configuration5.11 MEM IO Server5.11.1 IntroductionThe MEMORY IO Server is not a real IO server because values do not come from a peripheral. Memory Tags (Tags defined with the MEM IOserver) are rather sorts of variables that can be modified by a user input or by a BASIC application. These Tags are very useful for combiningdifferent Tags and consider the result as an actual Tag i.e. having data logging capabilities and alarm management capabilities like for all otherTags.5.11.2 SetupThere is no setup for the MEM eWON IO server.5.11.3 Tag name conventionIO Server configurationIO Server NameTopic NameItem NameMEMRETDON’T CAREIf no topic is specified, the Tag is a standard memory Tag. Its value is set to 0when the eWON boots and the Tag is read/write, it can be updated throughuser actions with script or web pagesIf topic is set to RET, the Tag is retentive, each change is saved to flash andwhen the eWON boots, the last value of the Tag is restored. This feature canbe convenient to use Tags as parameters.The MEM "Item Name" is insignificant, the Tag name is automatically copiedin the MEM address by the eWON, the user can change it, but the value willimmediately be overwritten again by the Tag name.Table 98: MEM IO server Tag name conventionImportant: RET values are saved in the FLASH memory, this is not an immediate operation and the FLASH memory can only bewritten and erased a limited (even if huge 100.000) number of times. This means that you should not use a BASIC script forchanging retentive values at very high rate. 1 Tag/Sec. is a maximum AVERAGE rate (occasional higher rates are not prohibited atall).RG-001-0-EN ver 1.5 eWON® - 20/03/2009 - ©ACT'L sa Page 124