LS Industrial Systems GIPAM - Protocols Overview; Data Frame Structure

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9 Protocols
9.1 Introduction
GMPC transfers the data from Central Control & Monitoring system(PC/MODEM)
to subordinate devices such as GIMAC/GIPAM if there is a response from them or vise
versa. And a structure of the data which is communicated between Central Control &
Monitoring System and subordinate devises will be defined in this chapter.
Meanwhile the other type of structure which is necessary to read status or change setting
value of GMPC is also defined in this chapter separately.
9.2 Basic structure of data frame for transmission.
Data that flows between GMPC and the Host system is transmitted frame by frame
and the basic structure of a frame is as follow.
[P1] + [P2] + [DEST] + [E:FN:LEN] + [DATA-0] + … + [DATA-n] + [ECC]
[ ] ; 1 BYTE
NAME SIZE VALUE DESCRIPTION
P1 1 BYTE 0xFF 1
st
PREAMBLE
P2 1 BYTE 0x00 2
nd
PREAMBLE
DEST 1 BYTE 0x00 – 0xFF I-NET ADDRESS for a receiving apparatus
0 Normal Response
E 1 BIT
1 Abnormal Response
00 Transmitting Junction
01 Time Setting
10 Setting Value of GMPC
FN 2 BIT
11 Reserve
LEN 5 BIT 0 - 16 Length of data willing to transmit [Byte]
DATA n BYTE 0x00 – 0xFF Details of BINARY DATA
ECC 1 BYTE 0x00 – 0xFF
Error Check Code(CHECK-SUM)
-The residual(The sum of data from [DEST]
to [DATA] / 256)