4 modbus tcp/ip slave – Toshiba T300MVi User Manual
Page 55
42
corresponding input register in the range of 1..9999 will be accessed.
Otherwise, a holding register of the same index as the assigned “register”
index will be accessed.
9999
10000
30001
39999
40000
1
30000
1
65535
65535
Holding Register
Accessed
Point’s “Register”
Assignment
65535
1
30000
30001
39999
40000
Input Register
Accessed
N
OT
A
CCESSIBLE
N
OT
A
CCESSIBLE
H
OLDING
I
NPUT
H
OLDING
Figure 29: "Register" Assignment and Resulting Register Type Accessed
•
Input (3X) registers are read-only. Attempts to write to a point associated
with an input register will result in an exception.
15.1.4 Modbus TCP/IP Slave
The interface supports Schneider Electric’s Modbus TCP/IP protocol, release
1.0. The unit is conformance class 0 and partial class 1 and class 2 compliant,
and allows up to 4 simultaneous Modbus TCP/IP client connections (sockets).
•
The “unit identifier” (UI) field of the request packets is ignored.
•
Standard socket timeouts are set to 30s, which means that if a particular
open socket experiences no activity for more than 30s, then the interface
assumes that the client or network has experienced some sort of
unexpected problem, and the interface will close that socket.
•
A “master” IP address and timeout time can be assigned to the unit. Each
point defined in the point database has the capability to be assigned an
optional failsafe timeout value. When an unexpected socket failure from