High-Speed Input and
Pulse Output Features
3–46
High-speed Input and Pulse Output Features
Signal pulses at X0 must meet certain timing criteria to guarantee an interrupt will
result. Refer to the timing diagram below. The input characteristics of X0 are fixed (it
is not a programmable filtered input). The minimum pulse width is 0.1 mS. There
must be some delay before the next interrupt pulse arrives, such that the interrupt
period cannot be smaller than 0.5 mS.
Time
External
Interrupt
X0
0.1 mS minimum
0.5 mS minimum
When the timed interrupt is selected, the HSIO generates the interrupt to ladder
logic. There is no interrupt “pulse width” in this case, but the interrupt period can be
adjusted from 5 to 999 mS.
Time
Timed
Interrupt
5 mS to 999 mS
The configurable discrete input options for High-Speed Interrupt Mode are listed in
the table below. Input X0 is the external interrupt when “0004” is in V7634. If you
need a timed interrupt instead, then V7634 contains the interrupt time period, and
input X0 becomes a filtered input (uses X1’s filter time constant by default). Inputs
X1, and X2, can only be filtered inputs, having individual configuration registers and
filter time constants. However, X0 will have the same filter time constant as X1 when
the timed interrupt is selected.
Input Configuration
Register
Function Hex Code
Required
X0 V7634 External Interrupt 0004 (default)
Uses X1’s time
setting in V7635
Filtered Input (when
timed interrupt is in use)
xxx4, xxx = INT timebase
5 - 999 ms (BCD)
X1 V7635 Filtered Input xx06 (xx = filter time)
0 - 99 ms (BCD)
X2 V7636 Filtered Input xx06 (xx = filter time)
0 - 99 ms (BCD)
Interrupt O1 is also available as an interrupt. This interrupt is independent of the
HSIO features. Interrupt O1 uses an internal timer that is configured in V memory
location V7647. The interrupt period can be adjusted from 5 to 9999 mS. Once the
interrupt period is set and the interrupt is enabled in the program, the CPU will
continuously call the interrupt routine based on the time setting in V7647.
Input Configuration
Register
Function Hex Code
Required
– V7647 High-Speed
Timed Interrupt
xxxx (xxxx = timer setting)
5 - 9999 mS (BCD)
External Interrupt
Timing Parameters
Timed Interrupt
Parameters
X Input / Timed
INT Configuration
Independent Timed
Interrupt
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