GE PACSystems RX7i Cpu Programmer's Reference Manual page 333

Chapter 6. Service Request Function
SVC_REQ 20 Example 1: Non-Extended Format
When Read_PLC transitions on, a value of 0 is moved to the parameter block, which is located at
%R00500, and the Controller Fault Table is read. When Read_IO transitions on, a value of 1 is moved
to the parameter block and the I/O Fault Table is read. When the SVC_REQ function successfully
executes, coil OK is turned on.
SVC_REQ 20 Example 2: Extended Format
When Read_PLC_Xt transitions on, the Extended Controller Fault Table is read. The parameter block
begins at %R00500. %R00500 contains the fault table type (Controller Extended); %R00501 contains
the starting fault to read, and %R00502 contains the number of faults to read starting with the fault
number in %R00501. When the SVC_REQ function successfully executes, coil OK is turned on.
318 PACSystems* RX7i, RX3i and RSTi-EP CPU Programmer's Reference Manual GFK-2950C