Myron L 767 - Manual (Page 15)

Component Identification/Calibration and Preventive Maintenance
4.3.4 MODEL 767
NOTE:
The following procedures are for the standard Model 767 Refer
to Section 4.3.5 for the procedures to calibrate a Model 767
which is equipped with the 420D self-powered isolated output
option.
STEP 1 Set the “RANGE” select switch to its “X1” position.
STEP 2 Connect an accurate DC voltmeter to the Recorder
output terminals TB1-6 & 7 with the positive (+) lead on
TB1 -6.
STEP 3 While holding the Calibration Test switch to its TEST
position, set the Main Calibration trimmer to indicate a
+10 volt reading on the test meter.
STEP 4 While holding the Calibration Test switch to its TEST
position, set the Front Panel Meter trimmer (R25) to
indicate a full scale reading on the front panel meter. If
the Monitor/Controller is equipped with the Remote
Meter option, adjust the Remote Meter trimmer (R28) in
the same manner.
4.3.5 MODEL 767 EQUIPPED WITH THE 420D OPTION
For this calibration procedure, the Monitor/Controller must be
connected to a conductivity sensor with the white and black
wires disconnected. If a sensor is not available, it can be
simulated with a 10,000 ohm resistor connected between
terminals TB1-10 and TB1-11.
STEP 1 Set the “RANGE” select switch to its “X1” setting.
STEP 2 While holding the Calibration Test switch (SW1) to its
TEST position, set the Main Calibration trimmer (R6) to
indicate a full scale setting on the front panel meter.
STEP 3 Connect an accurate DC voltmeter to the Recorder
Output terminals TB1-6 & 7 with the positive (+) lead on
TB1-6.
STEP 4 While holding the Calibration Test switch (SW1) to its
TEST position, set the Isolated Output trimmer (R57) to
indicate a +10 volt reading on the test meter.
STEP 5 Connect an accurate DC milliammeter to the 4-20 mA
output terminals TB1-4 & 5 with the positive (+) lead on
TB1-4.
STEP 6 Leaving the Calibration Test switch (SW1) at its
OPERATE position, set the 4-20 mA Null trimmer (R63)
to indicate 4 mA on the test meter.
STEP 7 While holding the Calibration Test switch (SW1) to its
TEST position, set the 4-20 mA Full Scale trimmer
(R60) to indicate 20 mA on the test meter.
STEP 8 If your Model 767 is equipped with the Remote Meter
option (RM), hold the Calibration Test switch (SW1) to
its TEST position and set the Remote Meter trimmer
(R28) to indicate a full scale reading on the remote
meter.
4.4 PREVENTIVE CARE
The Myron L Company recommends that the following
Preventive Care procedures be observed.
STEP 1 Try to prevent exposure to excessive heat and
moisture.
STEP 2 The Monitor’s main AC power source must be
protected against excessive voltage “spikes.”
STEP 3 Take care not to damage the Monitor during handling.
NOTE:
Daily, weekly or monthly maintenance schedules are based
upon the frequency of use and the severity of the Monitor’s
environment and operating conditions.
STEP 4 Repeat the Monitor’s Check-Out procedures to verify
satisfactory operation and/or isolate possible
troubleshooting symptoms.
STEP 5 Check all cable connections to ensure that they are
free of moisture and contamination.
STEP 6 Inspect and replace damaged component boards and
cable assemblies.
STEP 7 Periodically remove and clean and inspect the
conductivity Cell.
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