Instruction manual

IMP IMP/P Hot Runner Controllers Instruction Manual
7
temperature display will also flash. If
the temperature is within alarm limits,
the display will stop flashing, and the
leftmost digit will display closed-loop
mode (“O”).
5. Power to load indicator (the decimal
point of the leftmost digit) will be
on if any power is being applied to
the load.
6. When any of the T/C faults are
detected, output power will be cut off
automatically and the temperature
display will be blanked out. The
leftmost digit will show “ ” for (T/C
open), “ ” for (T/C reverse) or
“ ” for No Heat and flash twice
per second.
Automatic Operation with
CompuStep
®
System
When starting from cold, it is recommend-
ed that the CompuStep system be used to
lengthen heater life considerably.
1. Position the mode select switch to
CompuStep mode (“ ”).
2. Set the desired temperature on the
setpoint switch.
3. Turn on the AC power.
4. After reset delay, the measured
temperature will be displayed. If
temperature is less than 200°F
(93°C) the controller will enter the
CompuStep mode. This is indicated
by the step symbol “ ” on the left-
most digit. During this mode, the
controller gradually increases power
to load in small steps. After 5
minutes or when the temperature
reaches 256°F (124°C), the
controller will exit from CompuStep
mode and automatically go to
setpoint. Any thermocouple faults
detected during the 5-minute interval
will cause the CompuStep mode to
end prematurely. When CompuStep
ends, the controller will operate as
described in the Automatic
Closed-Loop Operation section. If
temperature is above 200°F (93°C),
controller will bypass CompuStep
and go directly to setpoint.
Manual Open-Loop
Operation
1. Position the mode select switch
to open-loop (“ ”).
2. Turn the AC power on.
3. After reset delay, the controller
will display the percentage of
output power as adjusted by the
power control knob. The
percentage power indicator will
be on. Thus 0.00 corresponds to
0% (no power) and 1.00 corre-
sponds to 100% (full power).
The leftmost digit will display
open-loop mode (“ ”).
75% power is shown as 0.75.
Manual Control Pre-Set
The following procedure can be used to
pre-set the Manual Power Control Knob
position in the event of a thermocouple
break in closed-loop operation.
A good thermocouple is required to start
with, as this procedure compares the
temperature attained using automatic
(closed-loop) control with that obtained
using manual (open-loop) control.
When the temperature is the same using
either automatic or manual control, then
the position of the Manual Power Control
Knob is correct.
Procedure for Manual
Control Pre-Set
a. Adjust controller for closed-loop
operation and obtain good molded
parts. This will adjust the controller to
the proper temperature.
b. Position the module select switch
to open-loop and set the manual
control knob to roughly 25%. Wait for
10 seconds, than momentarily switch
to closed-loop mode to examine the
temperature. If it is above the set
point, the manual power is too high to
maintain proper temperature. If it is
below setpoint, the manual power is
too low. Adjust the power control
knob accordingly, wait for 10