User`s guide

60 DC 900-1339H

FMP Programmer’s Guide

3.5 Overview of FMP Responses using Raw dlRead

Table 3–8 shows the valid FMP codes sent to your application in response to a Raw

dlRead request; the returned dlRead pOptArgs.usProtCommand field indicates the

response code. If the

dlRead return value is zero or positive, it indicates the number of

bytes read; if it is less than zero, an error has occurred. FMP error codes that can be

associated with the responses are described in Appendix C.

Note

The use of Normal dlRead requests (that is, without the optional

arguments parameter) is not recommended for FMP since error

reports would be indistinguishable from data received from the

remote application.

The following types of data can be returned from the ICP:

• Normal, transparent, and packed received data

• Error and conﬁrmation responses

• Acknowledgments (if the localAck DLI conﬁguration parameter is set to “no”)

• Reports in response to dlWrite information requests

3.5.1 Received Data

FMP provides three read types for receiving data: Normal Data, Transparent Data, and

Packed Data. Data blocks received from the serial line are sent to the client with the

dlRead pOptArgs.usProtCommand field set to one of these data types (see Table 3–8).

Note that the word “

SEND” is used in some of the receive command types. This is

because the same command code is used to both send and receive these data types.

The FMP software also provides two command variations (EOM and non-EOM) for

each type of read. When a data block ending with ETX is received on the serial line (BSC

and Structured Async lines), the ICP uses the EOM variation of the data type. This is