Fuji Electric PXZ Series Operation Manual page 11

AL Low Alarm Setpoint: The Low Alarm Setpoint is that
point of the process below which, the low alarm output
relay is energized. If the alarm type, programmed in the
secondary menu, includes an absolute value for the
Low Alarm Setpoint, enter the actual value you want
the alarm to be activated at regardless of what the
main setpoint is set for. If the alarm type includes a
deviation value for the Low Alarm Setpoint, enter the
number of units below main setpoint in which you want
the alarm to be activated at; the deviation alarm tracks
main setpoint.
Settable within the Input Range.
Not indicated without the alarm option.
AH High Alarm Setpoint: The High Alarm Setpoint is that
point of the process above which, the high alarm out-
put relay is energized. If the alarm type, programmed in
the secondary menu, includes an absolute value for
the High Alarm Setpoint, enter the actual value you
want the alarm to be activated at regardless of what
the main setpoint is set for. If the alarm type includes a
deviation value for the High Alarm Setpoint, enter the
number of units above main setpoint in which you want
the alarm to be activated at; the deviation alarm tracks
main setpoint.
Settable within the Input Range.
Not indicated without the alarm option.
TC Cycle Time (Output #1): The Cycle Time for output #1 is
that time where the output is on for a percentage of
that time and off for a percentage of that time, creating
a proportioning effect. The Cycle Time is only used
when the PXZ is used as a P, PI, PD, or PID controller
and when the output is time proportional as with the
relay or SSR/SSC drive outputs. The shorter the Cycle
Time, the higher the proportioning resolution is, and
better is the control, but there will be an increased
strain on the output device. Enter a value that is based
on the limitations of your controller's output type.
Setting range: 1 to 150 secs.
For relay output: Set to 30 secs or more
For SSR/SSC drive output: Set to 1 sec or more
For current output: Set to 0. (normally not indicated).
ON OFF
30 sec. Cycle Time
25% Output
ON OFF ON
20 sec. Cycle Time 20 sec. Cycle Time
25% Output 75% Output
ON OFF ON OFF
10 sec. 10 sec.
25% 75%
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ON OFF
30 sec. Cycle Time
75% Output
OFF
10
HYS Hysteresis: The Hysteresis is that area around the main
setpoint where the output does not change condition.
That area or deadband is intended to eliminate relay
chatter at setpoint for On/Off control applications. The
wider the Hysteresis, the longer it takes for the con-
troller to change output condition. The narrower the
Hysteresis, the less time the controller takes to change
output condition. When the Hysteresis is narrow, the
On/Off control is more accurate but the wear on the
output relay is increased. Enter a value which is small
enough to meet the control tolerance of the application
but large enough to eliminate relay chatter.
Setting range: 0 to 50% of full scale, set in E.U.
Hysteresis for On/Off action on dual outputs (heating
and cooling) is fixed at 0.5% of full scale.
Output OFF
Output ON
Setpoints
Narrow
Hystersis
Hb Heater Break Alarm Setpoint: If the heater's operating
current falls below this setpoint, the heater break
alarm output relay is energized. This option is used in
cases where the PXZ is controlling a bank of heaters
wired in parallel. A current transformer around the hot
lead going to the heater bank and connected to the
controller is tied with the controller's output and sens-
es the current used by the heater bank. If one or more
of the zones burnout, resulting in cold spots, the cur-
rent used by the defective heater bank is reduced. By
determining what the optimal current and the optimal
current minus one zone for the heater bank is, the
Heater Break Alarm setpoint can be calculated and
entered.
Setting Range: 0 to 50 amps.
Not indicated without the Heater Break Alarm output
option.
Not available on PXZ4, or with 4-20 mA DC outputs.
Detection is made only on a single-phase heater. This
function cannot be used when controlling a heater
with SCR phase-angle control.
Cycle Time, "TC," must be set at 6 secs. or higher
Refer to Appendix C for more details.
Optimal Current of
Heater Bank
Optimal Current of
minus
+
Heater Bank
Optimal Current of
less One Zone
Heater Bank
less One Zone
2
Output OFF
Output ON
Wide
Hystersis
Heater
=
Break
Alarm
Setpoint