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EXCEL 50/100/500/600/800 COMMUNICATION
EN2B-0092GE51 R0512
59
Remote trend buffer size formula For XD52-FC, XD52-FCS, and XC5210C controller (512 Kbytes of RAM):
N = (128 Kbytes - appl. size (in Kbytes) + 384 Kbytes) * 1024 bytes / 47 bytes
For all other controllers equipped with Flash EPROMS:
N = (128 Kbytes - appl. size (in Kbytes)) * 1024 bytes / 47 bytes
Hence, the maximum value of N is 10,327 trend values for large RAM controllers
and 1,960 trend values for all others containing Flash memory. This means that for
all Flash memory-equipped modules with a minimum application size of 38 Kbytes,
there will be 2,064 (1,960 + 104) trend values for front-end A and 104 trend values
each for front-end B and front-end C.
If an application being downloaded exceeds the application memory size, a warning
message will be displayed on the MMI, and the download will not be executed.
Excel 800
Excel 800 controllers provide a reserved Remote Trend Memory of 60Kbytes, which
allows a total of 2591 trend entries to be stored – see also diagram below:
2391 trend entries for front-end A
Plus 100 trend entries for front-end B
Plus 100 trend entries for front-end C
--------------------------------------------------
TOTAL = 2591 trend entries
REMOTE TREND BUFFER
60 KBYTES
= 2591 TREND ENTRIES
= 2391 PER FRONT-END A
+ 100 PER FRONT-END B
+ 100 PER FRONT-END C
APPLICATION (excluding RACL)
= max. 100 KBYTES
REMOTE TREND MEMORY:
60 KBYTES = 2501 TREND ENTRIES
TOTAL APPLICATION MEMORY
160
KBYTES
Fig. 25. Adjustable remote trend buffer example (Excel 800)
Unused application memory can be used for storing additional remote trend entries.
In order to do so, the adjustment range for the application memory size is the
following.
Table 23. Adjustment range of application memory size
application memory size trend values in remote trend buffer
maximum (default): 100 Kbyte 2501
example: 80 Kbyte 2936
minimum: 38 Kbyte 3851
MODEMFAQ
Detailed information and guidance can be obtained from the MODEMFAQ
document, which can be found on the following servers:
http://web.ge51.honeywell.de/dep/mc/HVAC_Products/Automation_and_Control/Ce
ntralPlantControls/Modem-Interface/MODMFAQ4.DOC