Omron SYSMAC C20K Operation Manual page 106

Timer and Counter Instructions
Description
General
Hard Reset
0002
In the hard reset mode, the reset signal must have an ON time of at least
250 µs.
Input
0001
250
The high-speed counter counts the signals input from an external device con-
nected to input 0000 and, when the high-speed counter instruction is ex-
ecuted, compares the current value with a set of ranges which have been
preset in DM words 32 through 63. If the current value is within any of the
preset ranges, the corresponding bit of a specified result word is turned ON.
The bit in the result word remains ON until the current value is no longer
within the specified range.
An internal buffer is incremented whenever bit 0000 goes from OFF to ON.
When the high-speed counter instruction is executed, the value in the count-
er buffer is transferred to counter 47 which serves as the count value storage
area.
When using the high-speed counter, the following bits are reserved and can-
not be used for any other purpose:
Input 0000 (count input)
Input 0001 (hard reset)
SR bit 1807 (soft reset)
TC 47 (present count value)
DM 32 to 63 (upper and lower limits)
Note If a power failure occurs, the count value of the high speed counter immedi-
ately before the power failure is retained.
The high-speed counter is programmed differently depending on how it is to
be reset. Two resetting modes are possible: hard-reset and soft-reset. The
hard reset is made effective or ineffective with the DIP switch in the CPU.
To use the hard reset, turn pins 7 and 8 ON. In this mode, input 0001 is the
reset input. When it is turned ON, the present value in the high-speed count-
er buffer is reset to "0000." When the reset is ON, the count signal from input
0000 is not accepted. When programmed with the hard reset, the high-speed
counter would appear as below.
µ
s max.
Address Instruction
HDM(61) 47
0000
10
0001
Section 5-11
Operands
LD 0002
HDM(61) 47
10
95