FieldServer FS-8704-12 - Manual (Page 8)

FS-8704-12 GE-EGD Driver Manual Page 8 of 23
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5.3.2 Driver Specific Map Descriptor P arameters
Column Title Function Legal Values
Node_Name Name of Node to fetch data from
One of the node names
specified in Section 5.2
Length
Number of points being consumed. For Bit values this
represents the number of bytes (i.e. number of points divided
by 8)
1 - 1000
Ge_ProducerId
This identifies the GE device producing the EGD data.
Although in decimal dot format, it is not an IP address and
does not necessarily correspond to the IP address of the GE-
Ethernet port producing the message. It corresponds to the
producer ID configured for the CPU producing the data.
The default value is typically the same as the IP address of the
producer but the value can be changed and it is possible for
one device to have multiple Ethernet interfaces and hence
multiple IP addresses.
Any change to the producerID must be matched by a similar
change in the consumer's configuration.
Nnn.nnn.nnn.nnn
Where nnn are in the range
0-255.
Ge_ExchangeId
Used with the ProducerID, to uniquely identify a packet of EGD
data. The driver uses these two parameters to match a
produced data packet with one or more passive Map
Descriptors.
Integer values >= 1
Ge_Data_Type*
Each produced data packet contains raw packed data. Nothing
in the message identifies the structure or type of the incoming
data. The Driver therefore cannot differentiate between byte,
integer, real ... numbers and requires the specification of this
keyword to unpack the data buffer.
Byte, Bit, Word, Dword, Int ,
Long, Float (4 byte IEEE real
number) or Double (8 byte
IEEE real number).
Ge_Offset*
If the producer has been configured to produce data of
multiple types in one data packet then multiple Map
Descriptors are required to decode them. The Ge_Offset is
used to point to the first byte in the data packet to be
processed by the Map Descriptor. Typically the Map
Descriptor for the 2nd, 3rd ... Map Descriptors associated with
one data packet will be non-zero.
0, Any positive integer