Emerson Rosemount 1181ORP TRANSMITTER, Instruction Manual, Page: 34 / 52

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MODEL 1181pH/ORP SECTION 3.0
START UP, AND CALIBRATION
*
Since the unit cannot display numbers more than +1999 (or +1.999, +19.99, +199.9), instead it will d1 followed by three blank dig-
its to indicate the situation of “overflow when the input exceeds the upper limit of the range. Therefore, if you wish the unit to read +2000 (or
+2.000, 20.00, +200.0), you may adjust the unit so that the display barely overflows.
Requirements Corresponding Parameters
READING READING READING DECIMAL POINT
APPLICATION RANGE
at 4mA at 12mA at 20mA
TOTAL SPAN
SETTING
pH 0-14 +0.00 +7.00 ±0.02 +14.00 1400 counts Turn on No. 2 of S1
pH 0-2 pH +.000 +1.000 ±.002 +2.000* 2000 counts Turn on No. 1 of S1
pH 2-4 pH +2.00 +3.00 ±0.01 +4.00 200 counts Turn on No. 2 of S1
pH 4-6 pH +4.00 +5.00 ±0.01 +6.00 200 counts Turn on No. 2 of S1
pH 6-8 pH +6.00 +7.00 ±.0.01 +8.00 200 counts Turn on No. 2 of S1
pH 8-10 pH +8.00 +9.00 ±0.01 +10.00 200 counts Turn on No. 2 of S1
pH 10-12 pH +10.00 +11.00 ±0.01 +12.00 200 counts Turn on No. 2 of S1
pH 12-14 pH +12.00 +13.00 ±.0.01 +14.00 200 counts Turn on No. 2 of S1
ORP –1000 - +1000mV –1000 000 ±0.03 +1000 2000 counts Turn off all switches
of S1
3.11 CALIBRATION
1. Turn on power supply and adjust to 24V ±.5V and
observe that display is functioning.
2. Set Model 213 to zero pH (+414 millivolts DC) and
adjust temperature compensation to obtain a read-
ing of +2.5V ±.05V on the voltmeter M2. Adjust the
zero pots on both the 1181 and on the LCD display
for 2.4V ±15 mV on M1 and 000 pH ±1 digit on the
display. Either one can be set first as one does not
affect the other.
3. Set Model 213 to 14 pH (–414 millivolts DC) and
adjust temperature compensation for –2.5V. Now
adjust the span control on the 1181 for 12.00V ±1
digit on the display.
4. Set Model 213 to 7.00 pH and check that M1 reads
7.20V ±15 mV and display is 700 pH ±1 digit.
3.12 END TEST
3.13 START-UP.
The LCD (liquid crystal display) is fac-
tory set for 000.00 reading at 4 mA to 100.0% at 20
mA. If this range is sufficient for the intended applica-
tion, no further adjustment to the display is necessary.
The standard procedures included in the 1181 instruc-
tion manual should be followed for proper instrument
start-up and calibration (see the start-up and calibra-
tion section of the instruction).
If a range other than the factory set range, or testing of
the LCD module is required, observe the following pro-
cedures. They are divided into two sections: (I) Testing
the module by itself, and, (ll) Testing it as an integral
part of the 1181 instrument.
3.14 LCD: MODULE ONLY. The object of this proce-
dure is to test and/or calibrate the LCD module for a
range other than the factory set range of 0-100%.
3.14.1 Test Equipment
1. DC power supply (Hewlett Packard 6217A or
equivalent) P1.
2. Digital DC current meter (Fluke 8050A or equiva-
lent) M1.
3. 1.0K, .25W, ±5% resistor (RL)
3.14.2 Set Up. The 1181 LCD unit under test, hence-
forth referred to as “the unit,” is connected in series
with an adjustable DC power supply P1, a 1.0K ohm,
±5% resistor and a digital current meter M1 as shown
in Figure 3-7.
3.14.3 Calibration.
1. Adjust the voltage output of P1 so that the current
meter M1 reads 4.00 mA then adjust the zero pot
on the LCD module (R8) until it displays 000 (see
Figure 3-6 and Figure 3-7).
2. Refer to Table 3-7. Find out the requirements and
corresponding parameters for the application.
3. Adjust power supply P1 so that the meter M1
reads 20.000 mA. Adjust the span pot (R4) of the
LCD until it displays the “total span” of this appli-
cation (see Figures 3-6 and 3-7, and Table 3-7).
4. Reduce power supply P1 until meter M1 reads
4.00 mA. Confirm that the unit still displays 000. If
not, readjust the unit following steps 1 through 4.
5. According to the “Decimal Point Setting” column of
Table 3-7 set switch S1 for this application (see
Figure 3-6).
6. Refer to Table 3-7. Adjust the zero pot (R8) for the
desired reading at 4 mA. Adjust the power supply
P1 for an output of 20.00 mA and confirm that the
reading coincides with the value in Table 3-6. If it
does not, readjust the unit following Steps 1
through 6.
7. Adjust P1 so that M1 reads 12.000 mA. The unit
should display “reading at 12 mA”.
TABLE 3-7. Parameters for Application