GE PACSystems RX7i Cpu Programmer's Reference Manual page 161

Chapter 4. Ladder Diagram (LD) Programming
Operands for BUS READ
Parameter Description
Length (??) The number of BYTEs, DWORDs, or WORDs.
1 to 32,767.
R Rack number. UINT constant or variable.
S Slot number. UINT constant or variable.
SS Subslot number (defaults to 0). UINT
constant or variable.
RGN Region (defaults to 1). WORD constant or
variable.
OFF The offset in bytes. DWORD constant or
variable.
The status of the operation. WORD
ST
variable.
Q Reference for data read from the module.
DWORD variable.
BUS_RD Status in the ST Output
The BUS_RD function returns one of the following values to the ST output:
0 Operation successful.
1 Bus error
2 Module does not exist at rack/slot location.
3 Module at rack/slot location is an invalid type.
4 Start address outside the configured range.
5 End address outside the configured address range.
6 Absolute address even but interface configured as odd byte only
8 Region not enabled
10 Function parameter invalid.
146 PACSystems* RX7i, RX3i and RSTi-EP CPU Programmer's Reference Manual
Allowed Operands
Constant
All except %S—%SC
All except %S—%SC
All except %S—%SC
All except %S—%SC
All except %S—%SC
All except variables located in %S—%SC,
and constants
All except variables located in %S—%SC,
and constants
Optional
No
No
No
Yes
Yes
No
Yes
No
GFK-2950C