Constant Registers - WAGO 750 Series Manual

122 • MODBUS Functions
Internal Variables

4.2.5.5 Constant Registers

The following registers contain constants, which can be used to test
communication with the master:
Register address 0x2000 (MODBUS Address 408193)
Value
Access
Description
Register address 0x2001 (MODBUS Address 408194)
Value
Access
Description
Register address 0x2002 (MODBUS Address 408195)
Value
Access
Description
Register address 0x2003 (MODBUS Address 408196)
Value
Access
Description
Register address 0x2004 (MODBUS Address 408197)
Value
Access
Description
Register address 0x2005 (MODBUS Address 408198)
Value
Access
Description
Register address 0x2006 (MODBUS Address 408199)
Value
Access
Description
Zero, GP_ZERO
Read
Constant with zeros
Ones, GP_ONES
Read
Constant with ones. Is –1 if this is declared as "signed int" or MAXVALUE
if it is declared as "unsigned int".
1,2,3,4, GP_1234
Read
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 apears, Motorola format is selected.
Mask 1, GP_AAAA
Read
This constant is used to verify that all bits are accessible to the fieldbus
master. This will be used together with register 0x2004.
Mask 1, GP_5555
Read
This constant is used to verify that all bits are accessible to the fieldbus
master. This will be used together with register 0x2003.
Maximum positiv number, GP_MAX_POS
Read
Constant in order to control arithmetic.
Maximum negativ number, GP_MAX_NEG
Read
Constant in order to control arithmetic.
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