To Read The Current Timer State And Value Without Changing Either - GE PACSystems RX7i Cpu Programmer's Reference Manual

6.2.5 To read the current timer state and value without changing
either:
Enter SVC_REQ 1 with this parameter block:
Address 3
Address + 1 ignored
Output
SVC_REQ 1 returns the timer state and value in the same parameter block references:
Address 0 = Normal Sweep
1 = Constant Sweep
Address + 1 Current timer value
If the word address + 1 contains the hexadecimal value FFFF, no timer value has been programmed.
SVC_REQ 1 Example
If contact OV_SWP is set, the Constant Sweep Timer is read, the timer is increased by 2 ms, and the
new timer value is sent back to the CPU. The parameter block is at location %R3050. The example
logic uses discrete internal coil %M0001 as a temporary location to hold the successful result of the
first rung line. On any sweep in which OV_SWP is not set, %M00001 is turned off.
GFK-2950C
Chapter 6. Service Request Function
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