PACSystemsâ„¢ 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
Bit pattern same as SP(00)
Major
79
(in hexadecimal)
Minor
80
(in hexadecimal)
7 ASCII characters + termination character (00h)
CPU Firmware Revision No.
Major (in BCD)
Minor (in BCD)
Communications Management
Module (CMM) Firmware Revision No.
PACSystems 43 (hexadecimal)
The amount of program memory occupied by the
logic program.
0000 = Run_Enabled 0100 = Halted 0001 = Run_Disabled 0101 = Suspended
0010 = Stopped 0110 = Stopped_IO_Enabled
CPU Major Type Codes: PACSystems 0x43
PACSystems Minor Types for CPU: refer to Message (17): Report Device Type
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: