EXPLANATIONS OF TERMS & FUNCTIONS
■
COUNT OVERFLOW
Three overflow modes are selectable with the Programming
Unit: Reset, Hold at 100% or Hold at 115%.
In Reset mode, the JPQ2 resets pulse count to zero as soon
as the input reaches the span count value. The span count
is equal to the zero count, thus the JPQ2 never outputs
100% in this sense.
In Hold at 100% mode, the JPQ2 stops counting at 100%
input. The count is held at the span count value, and the
DC output is held at 100%.
In Hold at 115% mode, the JPQ2 continues counting until
115% before holding the count and DC output.
In both modes, the Reset command input resets the count
to zero and the JPQ2 returns to the output equivalent to
zero count.
Input frequency does not affect the pulse counting of this
unit, however, the minimum of 5-microsecond pulse width
(50 msec. for mechanical contact input) is required to ac-
curately count the input pulses.
• Reset Mode
Input
Output
+
Reset
Short
Span Count
Min. 500 ms
Open
• Hold at 100% Mode
Input
Output
+
Reset
Short
Span Count
Min. 500 ms
Open
• Hold at 115% Mode
Input
Output
+
Reset
Short
Span Count
Min. 500 ms
Open
■
ALARM OUTPUT
Either Hi or Lo alarm output is supplied by a relay contact.
The alarm setpoint and the deadband (hysteresis) are ad-
justable with the Programming Unit in percentage of the
input range. The alarm setpoint is selectable from -15 to
+115%, while the deadband is from 0 to 20%.
Once the relay contact trips, it is reset to the normal posi-
tion when the counter is reset by the external reset com-
mand.
■
RESET INPUT
When a reset input is turned on, the accumulated count
in the internal counter goes back to zero. The JPQ2 com-
pares the input to this internal count for the alarm function,
therefore is affected by reset operations.
The reset input negative is connected to the input common.
Short across the terminals 6 and 11 for the minimum of
500 msec.
■
ZERO COUNT, SPAN COUNT
The count value equivalent to 0% output is called ‘Zero
Count,’ while that equivalent to 100% is called ‘Span Count.’
The zero count is usually set to 0, and selectable up to one
count below the span count. The span count is selectable
from one count above the zero count up to 99999999.
When a reset input is turned on, the output goes to 0% ac-
cording to the reset count.
With the ‘Hold at 115%’ overflow mode, the maximum count
range is from 0 to 99999999, and the maximum effective
count is 114999998.
■
DETECTING PULSE EDGE
• Open Collector & Mechanical Contact:
OFF (input monitor LED ON) to ON (input monitor LED
OFF) or ON to OFF
• Voltage Pulse
A pulse rise detected when the input voltage goes above
the detecting level (input monitor LED ON); a pulse sink
detected when it goes below the level (input monitor LED
OFF).
• Two-wire Current Pulse
The input resistor (100Ω) converts the current signal (0 –
25mA) into 0 – 2.5V. A pulse rise detected when the volt-
age goes above the detecting level (input monitor LED ON);
a pulse sink detected when it goes below the level (input
monitor LED OFF).
JPQ2
5-2-55, Minamitsumori, Nishinari-ku, Osaka 557-0063 JAPAN
Phone: +81(6)6659-8201 Fax: +81(6)6659-8510 E-mail: [email protected]
EM-1579 Rev.3 P. 3 / 8
