Emerson PACSystems RX3i - RTU Scratch Pad

PACSystems™ RX3i and RSTi-EP CPU Reference Manual Section 6
GFK-2222AK October 2019
Serial I/O, SNP & RTU Protocols 187
6.3.4 RTU Scratch Pad
The entire scratch pad is updated every time an external READ request is received by the
PACSystems RTU slave. All scratch pad locations are read only. The scratch pad is a byte-
oriented memory type.
6.3.4.1 RTU Scratch Pad Memory Allocation
SP Address
Field Identifier
Bits
7
6
5
4
3
2
1
0
00
CPU Run Status
0
0
0
0
See note.
78
01
CPU Command Status
Bit pattern same as SP(00)
02
03
CPU Type
Major
79
(in hexadecimal)
Minor
80
(in hexadecimal)
04 – 0B
CPU SNP ID
7 ASCII characters + termination character (00h)
0C
0D
CPU Firmware Revision No.
Major (in BCD)
Minor (in BCD)
0E
0F
Communications Management
Module (CMM) Firmware Revision No.
Major
Minor
10—11
Reserved
00h
12
Node Type Identifier
PACSystems 43 (hexadecimal)
13—15
Reserved
00h
16
RTU Station Address
1—247 (decimal)
17
Reserved
00h
18—33
81
Sizes of Memory Types
18—1B
Register Memory
%R size (words)
1C—1F
Analog Input Table
%AI size (words)
20—23
Analog Output Table
%AO size (words)
24—27
Input Table
%I size (bits)
28—2B
Output Table
%O size (bits)
2C—2F
Internal Discrete Memory
%M size (bits)
30—33
User Program Code
The amount of program memory occupied by the
logic program.
34—FF
Reserved
00h
78
0000 = Run_Enabled 0100 = Halted 0001 = Run_Disabled 0101 = Suspended
0010 = Stopped 0110 = Stopped_IO_Enabled
79
CPU Major Type Codes: PACSystems 0x43
80
PACSystems Minor Types for CPU: refer to Message (17): Report Device Type
81
Four bytes hold the hexadecimal length of each memory type with the most significant word reserved for future expansion. For example, the
default register memory size of 1024 words (0400h) would be returned in the following format:
Word
Least
Significant
Most
Significant
SP Byte
18
19
1A
1B
Contains
00
04
00
00