Performing Commands Using Function Code 10H; Using The User Definable Memory Map - GE MM300 Manual

PERFORMING COMMANDS USING FUNCTION CODE 10H

Performing Commands Using Function Code 10H

Using the User Definable Memory Map

2–66
Commands can be performed using function code 16 as well as function code 5. When
using FUNCTION CODE 16, the Command Function register must be written with a value of
5. The Command Operation register must be written with a valid command operation
number. The Command Data registers must be written with valid data; this is dependent
upon the command operation.
For example, consider a request for slave 17 to perform command operation 1 (RESET): The
master/slave packets have the following format:
Table 2-9: Master/slave packet format for performing commands
MASTER TRANSMISSION
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS
NUMBER OF SETPOINTS
BYTE COUNT
DATA 1
DATA 2
CRC
SLAVE RESPONSE
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS
NUMBER OF SETPOINTS
CRC
The MM300 contains a User Definable area in the memory map. This area allows re-
mapping of the addresses of any Actual Values or Setpoints registers. The User Definable
area has two sections:
1. A Register Index area (memory map addresses 020BH-0287H) that contains 125
Actual Values or Setpoints register addresses.
2. A Register area (memory map addresses 020BH-0287H) that contains the data at the
addresses in the Register Index.
Register data that is separated in the rest of the memory map may be re-mapped to
adjacent register addresses in the User Definable Registers area. This is accomplished by
writing to register addresses in the User Definable Register Index area. This allows for
improved throughput of data and can eliminate the need for multiple read command
sequences. The User Definable Register Index is stored as a setpoint and therefore it is
"remembered" even when the power is removed.
CHAPTER 2: RS485 INTERFACE (MODBUS RTU)
BYTES EXAMPLE
1 11
1 10
2 00 80
2 00 02
1 04
2 00 05
2 00 01
2 7E CE
BYTES EXAMPLE
1 11
1 10
2 00 80
2 00 02
2 42 B0
MM300 MOTOR MANAGEMENT SYSTEM – COMMUNICATIONS GUIDE
DESCRIPTION
message for slave 17
store multiple
setpoints
setpoint address 00
80
2 setpoints = 4 bytes
total
4 bytes of data
data for address 00
80
data for address 00
81
CRC error code
DESCRIPTION
message from slave
17
store multiple
setpoints
setpoint address 00
80
2 setpoints
CRC error code