96VTR Datasheet, PDF (9/15 Pages) Extech Instruments Corporation. – 1/4 DIN Process Controller

HiLt: High limit (of Span or Range). Set High Limit higher than the highest expected SV
and PV display. Note that the high limit setting is limited by the range of the type
of input used (refer to Section 2.2 for ranges).
9. PARAMETERS IN THE FOURTH PROGRAMMING LEVEL
Press and hold the SCROLL and RETURN keys simultaneously for 5 seconds to enter
this level from the previous programming level. To return to normal operation at any
time, press the RETURN key.
LoCA and HiCA: Low and High Input Calibration values used for engineering units
scaling. Refer to Section 9.1 below for details.
tunE: Auto-tuning ‘automatic initialization mode’ selection. Select the criteria by which
the controller initiates an automatic Auto Tune session. Set this parameter as
desired from the Table in Section 9.2. To activate Auto Tune manually, refer
to Section 9.2.
9.1. CALIBRATION
Important Note: Special equipment is required to perform calibrations. Do not initiate
the calibration process unless fully prepared to do so.
a. "LoCA" (Low Calibration) is the first parameter to appear in this level.
b. For temperature inputs, connect a Thermocouple (mV) or RTD (resistance)
simulator to the controller's input terminals. For a process DC input, use a 4-20mA
or 1-5VDC signal, depending on the input type of the controller.
c. Apply the low input signal to the controller which corresponds to the range you are
using, i.e., for 4-20 mA inputs, 4 mA would now be applied to the controller.
d. Use the UP/DOWN arrow keys to set the value which will display when a 4mA
signal is applied to the controller. For example, for a 4-20mA unit to display from –
50 to +150, set ‘LoCA” to –50.
e. Press and hold the RETURN key for at least 5 seconds and the parameter on the
display will change from "LoCA" to "HiCA" (High Calibration). The Low Calibration
value is now written into the controller's non-volatile memory.
f. Apply the high input signal to the controller which corresponds to the range you are
using. For example, for a 4-20mA input controller, apply a 20mA signal.
g. Use the UP/DOWN arrow keys to set the value which will display when a 20mA
signal is applied to the controller. For example, for a 4-20mA unit to display from –
50 to +150, set ‘LoCA” to +150.
h. Press and hold the RETURN key for at least 5 seconds. The display will change
from "LoCA" to "SP". The High Calibration value is now written into the controller's
non-volatile memory.
i. Input a signal midway between the Low and High Calibration signals previously
applied (12mA in the example for a 4-20mA input) and verify that the display shows
a value midway between the high display and the low display. For the example
above, for a -50 to +150 display range, a 12mA input will display +50. If not, try the
calibration procedure again.
j. Press the RETURN key when complete to return to normal operation.
9.2 AUTO TUNING
9.2.1 Auto Tune Initialization Modes
The Controller has the capability to start an Auto Tune session automatically. If this is
desired, select the conditions whereby an Auto Tune session will automatically begin
from Table III below. The controller defaults to Setting = ‘0’ (user initiates an Auto Tune
session). To manually initiate an Auto Tune session follow the procedure in Section
9.2.2.
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96VTR Ver. 2.0 11/99