Operator`s manual

21X MICROLOGGER OVERVIEW
OV-12
will be inserted at that point in the table,
advance through and enter the parameters.
The Instruction that was at that point and all
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 not
entered until A is keyed.
The next example program uses the panel
temperature measurement but uses timed
intervals for output instead of every execution.
To get ready for the example, we will delete
Instructions 86 and 70.
Display Shows
Key (ID:Data) Explanation
: LOG1 21X is in *0 Mode
*1 01:00 Enter Program Table 1.
2A 02:P86 Jump to 2nd instruction in table; Instruction 86,
DO.
#D 02:P70 Delete Instruction 86. Second instruction is now
70.
#D 02:P00 Delete Instruction 70. Second instruction is now
vacant.
*0 :LOG1 Return to *0 Mode
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
temperature, the reference junction temperature
must be known.
The 21X is shipped with a short thermocouple
wired to differential channel 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.
Instruction 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. If there were several TCs, they
could be wired to sequential input channels and
the number of TCs would be entered in
Parameter 1. The 21X would measure all of the
TCs.
Parameter 2 is the full scale voltage input range
to use when making the measurement. Type T
TC signals are very small, approximately
40µV/
o
C difference in temperature between the
measurement and reference junction. If we use
a range code of 1 (±5 mV full scale, slow
integration), the TC voltage will not exceed the
input range as long as the measurement
junction is within 125
o
C of the panel
temperature.