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21X MICROLOGGER OVERVIEW
will be insefted
at
that point
in
the table,
advance
through and enter the parameters.
The Instruction that was
at
that point and
al
instructions
following
it
will be pushed down to
follow
the inserted instruction.
An instruction is deleted by advancing to the
instruction number (P
in
display) and keying #D
(Table OV3-2).
To change the value entered
for a parameter,
advance
to parameter and key
in
the
correct
value
then
key
A.
Note that
the new value
is
entered
untilA
is keyed.
The next example program uses the panel
temperature measurement but uses timed
intervals
for output instead
ol
every execution.
To get ready for the example, we will delete
'fnstructions 86 and
70.
Display Shows
(lD:Data)
Explanation
: LOG1
01:00
02:P86
O2:P7O
02:P00
:LOG1
OV4.3 SAMPLE
PROGRAM
2
Our second example is more representative of
a
data collection
situation. This time the panel
temperature
will be used as the reference
temperature for
a
type
T (copper-constantan)
thermocouple
(TC). Thermocouples
measure
the
temperature relative to their reference
junction
temperature. To obtain the absolute
temperatu re,
the
refe
rence
j
u
nction temperatu
re
must be known.
The
21X
is
shipped with
a
shorl thermocouple
wired
to differentialchannel
5.
The
copper lead
is
connected to
the high input (H) and the
constantan lead
is
connected to
the low input
(L).
We'll read the sensor every 5 seconds, and
store one hour average temperatures along with
a
daily maximum and minimum temperature
and the times
at
which they
occur.
The date
and time will also be stored with the data.
ov-l2
21X is
in
*0 Mode
Enter Program
Table
1.
Jump to 2nd instruction
in
table; Instruction
86,
DO.
Delete Instruction
86.
Second instruction is now
70.
Delete Instruction
70.
Second instruction is now
vacant.
Return to
*0 Mode
lnstruction 14 measures TC temperature with a
differential
voltage measurement. The first
parameter
is
the number of times to repeat the
measurement.
There is only one thermocouple,
so we enter
a
1.
lf
there were several TCs.
could
be
wired to sequential input channels and
the number
of
TCs
would be entered
in
Parameter
1.
The 21X
would measure all of
TCs.
Parameter
2
is
the
full scale voltage input range
to use when making the measurement. Type T
TC signals are very small, approximately
4OuVPC difference
in
temperature between the
measurement
and reference
junction.
lf
we use
a range code of
1
(t5
mV
full scale, slow
integration), the TC voltage
will
not
exceed the
input range
as long as the measurement
junction
is
within
125oC of
the panel
temperature.
Key
2A
*1
#D
#D
*0
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