219
Timer and Counter Instructions Section 5-15
Refer to 1-5-4 , 1-6-4 , and 1-7-2 for more detailed descriptions of using inter-
val timer interrupts. STIM(69) is also described in more detail after the table.
Note 1. In CQM1 PCs, interval timer 0 cannot be used when a pulse output is being
output by the SPED(64) instruction.
2. In CQM1 PCs, interval timer 2 cannot be used when high-speed counter 0
operation has been enabled in DM 6642 of the PC Setup.
Starting Interrupts Set C1=000 to 002 to start timers 0 to 2 to activate a one-shot interrupt. Set
C1=003 to 005 to start scheduled interrupts using timers 0 to 2.
C2, which specifies the timer’s SV, can be a constant or the first of two words
containing the SV. The settings are slightly different depending on the method
used.
If C2 is a constant, it specifies the initial value of the decrementing counter
(BCD, 0000 to 9999). The decrementing time interval is 1 ms.
If C2 is a word address, C2 specifies the initial value of the decrementing
counter (BCD, 0000 to 9999), and C2+1 specifies the decrementing time
interval (BCD, 0005 to 0320) in units of 0.1 ms. The decrementing time inter-
val can thus be 0.5 to 32 ms.
C3 specifies subroutine number 0000 to 0255 (0000 to 0127 in the CQM1-
CPU11/21-E, 0000 to 0049 in the CPM1/CPM1A/SRM1 PCs).
Note The time required from interval timer start-up to time-up is:
(the content of C2)
× (the content of C2+1) × 0.1 ms
Reading Timer PVs Set C1=006 to 008 to read the PVs of timers 0 to 2.
C2 specifies the first of two destination words that will receive the timer’s PV.
C2 will receive the number of times the decrementing counter has been dec-
remented (BCD, 0000 to 9999) and C2+1 will receive the decrementing time
interval (BCD in 0.1 ms units).
C3 specifies the destination word that will receive the time which has elapsed
since the last time the timer was decremented (BCD in 0.1 ms units).
(Must be equal to or less than the decrementing time interval set in C2+1.)
Note The time that has elapsed since the timer was started is computed as follows:
(Content of C2
× (Content of C2 + 1) + Content of C3) × 0.1 ms
Stopping Timers Set C1=010 to 012 to stop timers 0 to 2.
Function Timer C1 value Applicable PCs
Starting timers 0 000 CQM1/CPM1/
CPM1A/SRM1
1001 CQM1 only
2002
Starting scheduled interrupts 0 003 CQM1/CPM1/
CPM1A/SRM1
1004 CQM1 only
2005
Reading timer PV 0 006 CQM1/CPM1/
CPM1A/SRM1
1007 CQM1 only
2008
Stopping timers 0 010 CQM1/CPM1/
CPM1A/SRM1
1011 CQM1 only
2012