256 Fieldbus Communication
WAGO-I/O-SYSTEM 750
750-880, 750-880/025-000 ETHERNET Programmable Fieldbus Controller
Manual
Version 1.0.1
Pos: 109.56 /Alle Serien (Allgemeine Module)/Feldbuskommunikation/MODBUS/Zugriff auf Registerwerte - Konstantenregister 0x2000 bis 0x2008 @ 3\mod_1235462025437_21.doc @ 27639 @ 4 @ 1
12.2.5.6 Constant Registers
The following registers contain constants, which can be used to test
communication with the master:
Table 175: Register address 0x2000
Register address 0x2000 (8192
dec
)
Value
Zero, GP_ZERO
Access
Read
Description
Constant with zeros
Table 176: Register address 0x2001
Register address 0x2001 (8193
dec
)
Value
Ones, GP_ONES
Access
Read
Description
Constant with ones
• –1 if this is declared as "signed int"
• MAXVALUE if it is declared as "unsigned int"
Table 177: Register address 0x2002
Register address 0x2002 (8194
dec
)
Value
1,2,3,4, GP_1234
Access
Read
Description
This constant value is used to test the Intel/Motorola format specifier. If the
master reads a value of 0x1234, then with Intel format is selected – this is the
correct format. If 0x3412 appears, Motorola format is selected.
Table 178: Register address 0x2003
Register address 0x2003 (8195
dec
)
Value
Mask 1, GP_AAAA
Access
Read
Description
This constant is used to verify that all bits are accessible to the fieldbus master.
This will be used together with register 0x2004.
Table 179: Register address 0x2004
Register address 0x2004 (8196
dec
)
Value
Mask 1, GP_5555
Access
Read
Description
This constant is used to verify that all bits are accessible to the fieldbus master.
This will be used together with register 0x2003.
Table 180: Register address 0x2005
Register address 0x2005 (8197
dec
)
Value
Maximum positive number, GP_MAX_POS
Access
Read
Description
Constant in order to control arithmetic.
