Yokogawa In-Situ Gas Analyzer TDLS200 - Manual (Page 123)

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IM 11Y01B01-01E-A 6th Edition :Feb 13, 2013-00
<8. VALIDATION AND CALIBRATION>
Types of Validation Reading:
There are two different ways in which the validation reading can be presented.
Validation Only: When this method is selected, the analyzer will calculate AND output the result as the
actual gas value e.g. instrument air if validated correctly would show AND output 20.9% O2 as the validation
result. Another example would be 5% CO being the validation gas value and the hence the calculated AND
output value (when Track is selected for 4-20mA) would also be 5%. In some cases, the output range might
be scaled below the validation gas value (e.g. 0-10% O2 while validating with 20.9% O2). In these cases, the
Validation Only result can be scaled down to fit within the configured 4-20mA output range.
Example: 0-5,000ppm CO is set for 4-20mA output range. 5% CO is used for the validation gas. To make the
Tracked 4-20mA output read 5,000ppm during validation at the DCS, the Factor should be 0.1. To make the
5% CO validation gas read 2,500ppm (at the DCS), the factor should be set to 0.05.
Process + Validation: When this method is selected, the analyzer will calculate AND output the result as a
response relative to the process conditions. The displayed result on screen will be shown as Expected result
(say 20.9% O2) compared to actual result (say 20.7%O2) however, if Track mode is selected for the 4-20mA
then the mA will track the result as if the validation gas was process gas.
Example: If the validation gas is introduced without the analyzer knowing, and the process reading changes
by 2% O2 then this should be addition amount during each validation. So if process reading is 5% O2 then,
when an on-line validation is performed the reading (and Tracked 4-2mA) will change to 7% O2.
Example: If the introduction of 5% CO causes a 600ppm change in the process reading, then this will be the
expected step change in reading (and Tracked 4-20mA) during on-line validations.
Initiating Validation:
There are several ways in which the Automatic Validation sequence can be initiated:
• Remote Contact – The analyzer has the ability to monitor a pair of voltage free contacts. These
contacts would typically be located at the DCS or a simple switch located near the analyzer. The
analyzer continuously monitors the remote contacts (or switch) for a return voltage (24 VDC
generated by the analyzer). When the contacts close, the return voltage is sensed and the Auto
Validation sequence is initiated.
• Local User Interface – The TDLS200 software allows for the user (either through a laptop PC running
VAC software or via installed 6.5” display & Keypad) to initiate the Auto Validation sequence. The
operator would be at the analyzer in this case.
• Preset Timed – The TDLS200 software allows for the analyzer to automatically initiate the Auto
Validation sequence based on a user configurable timed basis.
• URD & Laptop PC with VAC software – The TDLS200 software allows for the user through a laptop
PC running VAC software to initiate the Auto Validation sequence. The operator would be at the URD
with the laptop PC plugged in to the Ethernet port on the URD Feed Through board.
• RIU with VAC software – The TDLS200 software allows for the user through an RIU running VAC
software to initiate the Auto Validation sequence. The operator would
be at the RIU in this case.