FieldServer FS-8700-80 instruction manual DACHILLER1

McQuay Micro Tech Open Protocol Driver Manual Page 15 of 35

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 device’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. The 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.

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