GIC 151A12B, Instructions Manual

Page: 15 / 47

15
7. Switch OFF the instrument power and then switch it ON to start tuning if “Auto” is set
as “1” or “2” or by pressing config. key programmed as “stAt”. Flashing LED AT indicates
the activation of Auto-tunning function. To start the auto tune following condition needs
to satisfy:
if “Func“ is “HEAT”
PV < [SP - |SP/5|] if soft start is configured
OR
PV < [SP - |SP/3|] if soft start is not configured
if “Func“ is “COOL”
PV > [SP + |SP/5|] if soft start is configured
OR
PV > [SP + |SP/3|] if soft start is not configured
If the above conditions are not satisfied at the start of auto tune, the display will show
"ErAt" message and the instrument will take the control conditions according to previously
programmed PID. To make 'ErAt' disappear Press enter key. If auto tune is not completed in
10 hours, the instrument shows 'NoAt' on display. The cycle in progress in automatically
get stopped in case of sensor error. After correct PID parameters are tuned, the calculated
values are stored in instrument memory.
14.0 RAMP AND SOAK #
5,6,7,8
:
1. The PR-69 has provision for three ramps and three soaks corresponding to sP1, sP2
and sP3.
2. All parameters related to ramp functions in group ‘rEg’
3. Three strategies have been adopted that determine the state of ramp and soak in
case of power resumption after failure.
14.1 Power Down Resumption Mode (Prmd):
a. cont: The device keeps in memory the last set point value before the power failure.
After resumption, it starts from the same value and continues the profile. In case of
soak stage once the power is resumed, the stage continues for the remaining time.
b. rbck: The device starts from present Pv value and continues with the profile. In case
of power failure in soak stage, once the power is resumed and if Pv is not equal to the
target sP of the given soak stage, then starting from Pv the sP ramps up to the target sP
value with the slope of previous ramp. Once target sP is reached, device move to soak
stage which continues for the remaining time.
c. rsEt: On power failure, the entire ramp and soak profile is reset. At the end of the
profile irrespective of Pwrd, the device switches OFF all the control outputs.