Yokogawa In-Situ Gas Analyzer TDLS200 - Manual (Page 38)

38
IM11Y01B01-12E-A
1st Edition
high-process-temperature analyzer (with a capacitor on R3), the raw detector signal is within
requirement if
MIN is between -4.0 and -8.5 .
c. If the raw detector signal is too low (other than a and b), change either R22 or R23 to the next
greater value available in the resistor bag, and then go back to STEP 7. How to decide which
resistor to change:
i. If the current R22 value is greater than the current R23 value, change R23 to the
next greater value available in the resistor bag.
ii. If the current R22 value is same as the current R23 value, change R22 to the next
greater value available in the resistor bag.
iii. If the current R22 and R23 are already 24.3kΩ (the greatest value available in the
resistor bag), please contact Yokogawa for assistance.
9. Close the detector enclosure. Write down the final values of R21, R22 and R23 below for record.
R21 = ____________; R22 = ____________; R23 = ____________.
10. Enter these new resistor values into the analyzer configuration under Advanced Menu >
Configure > System > Adjustable Resistors > Detect – R21, Detect – R22, and Detect – R23. All
resistor values are entered in K ohm unit.
11. Keep the resistor bag and this procedure document by customer. DO NOT leave them in the
detector box or throw them away.
TIPS
• How to remove a gain resistor? On the detector board, find the location of the gain resistor. Please
note that the resistor is not soldered but resting in sockets. Carefully remove the resistor from the
socket on the board. Since the analyzer is still powered on, please take extreme caution to
prevent a short circuit on the board, i.e. loose wires or touching adjacent components with pliers
or tool used to remove resistor.
• How to install a new gain resistor? First try the new resistor by molding and clipping the resistor
leads to fit into the socket. Then carefully insert the resistor into the socket on the detector board.
Since the analyzer is still powered on, please take extreme caution to prevent a short circuit on
the board, i.e. loose wires or touching adjacent components with pliers or tool used to install
resistor.
• Please keep the factory/original gain resistors in the resistor bag as they will be used in the future
for offline calibration or test.
•
The raw detector signal ( MAX-MIN ) is proportional to R21·R22·R23. Usually R21 is maintained as
factory value. R22 and R23 are optimized in the field. We want to avoid the situation where one of
R22 and R23 resistors has extreme low resistance and the other one has extreme high resistance.
The analyzer gives best performance when R22 and R23 are balanced. Based on this relation
between raw detector signal and gain resistors, service technician or customer can select R22 and
R23 faster with the help of a calculator.
•
Multiple alignment actions might be needed if Detector Signal High fault happens. Reduce the gain
resistor first as described in STEP 8-a, and then optimize the alignment again.
NOTE: If the alignment has been performed on a ‘cold’ (shut-down) heater/furnace, then it is
highly recommended when the heater/furnace is at normal operating temperature, the
transmission/alignment be checked again to ensure >10% (ideally >25%) transmission exists and
that there are no alarms. Validation gas should also be introduced through the validation cell to
ensure peak response, especially if a line-locking gas is not being used.