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10.8.
CALIBRATING A CHANNEL TO ITS INCOMING SIGNALS
The
POWER
POD
-400
is designed to accept the input from almost any transducer that operates in the
ranges of zero to five volts, zero to ten volts or four to twenty milliamps. In most cases, transducers are
capable of having their minimum signal and maximum signal adjusted to correspond with the minimum
(ZERO) and maximum (SPAN) unit-of-measure that they are designed to reflect.
For example:
A transducer designed to output 0 volts while reading a temperature of 0 degrees centigrade and output 5
volts while reading 100 degrees centigrade is connected to channel one of the
POWER
POD
-400
.
In actuality, the transducer is sending -0.23 volts at 0 degrees and 5.11 volts at 100 degrees. By zeroing
channel one of the
POWER
POD
-400
while reading the low signal from the transducer, the display will be
000.0 when the temperature is 0
°
C. Like wise, by setting the CAL value to 100.0 while reading the 5.11
volt signal causes the
POWER
POD
-400
to display 100.0 when the temperature is actually 100
°
C.
This procedure will not account for any non-linearity in any transducer’s output. That is, the
accuracy/calibration of any transducer must be independently set, checked and verified before
connecting to the POWER
POD
-400, or, the transducer/ POWER
POD
-400 combination must be
calibrated together as a system, if the accuracy of the whole system is to be known.
10.8.1.
Resetting the Zero Only
While the
SETUP/CAL
menu is being displayed and after making a selection from the
CHANNEL
SELECT
menu, select
CALIBRATE
by pressing
the number
7
key
followed by
ENTER
, then choose
ZERO ONLY
by pressing the number
1
key and
ENTER
. The
ZERO
menu will be displayed which also
displays the selected channel number and the signal being received. If this signal is an acceptable signal
for zero, press the
ENTER
key to accept it. If the indicated signal is not an acceptable level for reading
zero, the operator has an opportunity at this stage to correct any problems while reading the incoming
signal before pressing the
ENTER
key and accepting it. Alternatively, the operator can press ESC to exit
the
SETUP/CAL
mode and return to it later. After accepting the displayed signal level as the zero point,
the display returns to its previously programmed settings. See Appendix D.
10.8.2.
Resetting the Span Only
After selecting a channel in the
CHANNEL SELECT
portion of the
SETUP/CAL
menu, press
7 +
ENTER
to select
CALIBRATE
.
SPAN ONLY
is selected by pressing number
3 + ENTER
. The
SPAN
window is displayed which contains the chosen channel and the incoming signal on that channel.
If the displayed signal is an acceptable full r ange value, press
ENTER
to accept it. The previously
programmed display returns with the selected channel now displaying the
CAL
’d value. If the incoming
