McQuay Micro Tech Open Protocol Driver Manual Page 15 of 35 FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web: www.fieldServer.com
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5.3.4. Map Descriptor Example – Strategy 1. This example illustrates how you can configure the FieldServer as a McQuay Micro Tech Open Protocol Server. A single Map Descriptor is used
to emulate a McQuay de vice’s memory as one large single block of bytes. Any requests in the address range 1-0x270F can be serviced by this
one Map Descriptor. T he strategy is simple but has one drawback; a large Data Array which will be mostly empty is used. This does not affect
performance but does use the FieldServer’s memory resource.
When a poll is received, the driver looks through the Map Descriptor and finds one with a matching node and one whose address and length cover
the poll’s address.
Map_Descriptor_Name ,Data_Array_Name ,Data_Array_Offset ,Function ,Node_Name ,Address ,Length
Chiller1_emulation ,DA_CHILLER1 ,0 ,Passive ,Chiller1 ,1 ,10000
Ensure that Data Array’s
length is at least as long
as the Map Descriptor’s.
A data format of BYTE is
appropriate,
Passive means that the Map
Descriptor is used to respond
to polls but does not generate
any poll’s itself.
The Node name connects the
Map Descriptor to a Node
definition and possibly to a
port.
10,000 is the maximum length of a
Data Array so there is no point in
making the Map Descriptor longer.