Allen-Bradley MicroLogix 1400 Instruction Manual page 128

efesotomasyon.com - Allen Bradley,Rockwell,plc,servo,drive
126 Using the High-Speed Counter and Programmable Limit Switch
Publication 1766-RM001A-EN-P - October 2008
• Load new HSC parameters using the HSL instruction. See HSL -
High-Speed Counter Load on page 130.
The data loaded into the low preset must greater than or equal to the data
resident in the underflow (HSC:0.UNF) parameter, or an HSC error is
generated. (If the underflow and low preset values are negative numbers,
the low preset must be a number with a smaller absolute value.)
Overflow (OVF)
Description Address
OVF - Overflow HSC:0.OVF
The OVF (Overflow) defines the upper count limit for the counter. If the
counter's accumulated value increments past the value specified in this
variable, an overflow interrupt is generated. When the overflow interrupt
is generated, the HSC sub-system rolls the accumulator over to the
underflow value and the counter continues counting from the underflow
value (counts are not lost in this transition). The user can specify any
value for the overflow position, provided it is greater than the underflow
value and falls between -2,147,483,648 and 2,147,483,647.
To load data into the overflow variable, the control program must toggle
(low to high) the Set Parameters (HSC:0.0/SP) control bit. When the SP bit
is toggled high, the data currently stored in the HSC function file is
transferred/loaded into the HSC sub-system.
Data loaded into the overflow variable must be greater than or equal
TIP
to the data resident in the high preset (HSC:0.HIP) or an HSC error is
generated.
Underflow (UNF)
Description Address
UNF - Underflow HSC:0.UNF
The UNF (Underflow) defines the lower count limit for the counter. If the
counter's accumulated value decrements past the value specified in this
variable, an underflow interrupt is generated. When the underflow
interrupt is generated, the HSC sub-system resets the accumulated value
Data Format Type
long word (32-bit INT) control
Data Format Type
long word (32-bit INT) control
User Program Access
read/write
User Program Access
read/write