46
8015383/ZUQ7/V1-3/2020-06 | SICK
O P E R A T I N G I N S T R U C T I O N S | TRANSIC151LP
Subject to change without notice
6
ADJUSTMENT
6.1.2
Calibration and adjustment in the process
▸
The TRANSIC151LP does not have to be removed from the process with this adjustment
method.
▸
Feed the reference gas through the optional calibration gas inlet in the bottom of the
TRANSIC151LP transmitter.
Typical calibration accuracy is within ±0.2% O
2
for a reference gas volume flow of
5 ...9 l/min. Calibration uncertainty increases when the volume flow is significantly
below 5 l/min.
The effect of the process gas flow rate (in the range 0 ... 20 m/s) on adjustment precision
is negligible. Adjustment precision decreases with a higher process gas flow rate.
The strength of unwanted counter diffusion through the filter depends on the O
2
concentration difference between reference gas and process gas. For example, if you are
using 100% N
2
as a reference and the process gas has 2% O
2
, the result is better than
when the process gas has 21% O
2
.
6.1.2.1
Connections and systems
The calibration gas inlet of the TRANSIC151LP is fitted with a Swagelok screw fitting for
pipes with 6 mm outer diameter. The non-return valve has an opening pressure of about
1.7 bar. The first opening pressure can be higher when the non-return valve has not been
used for some time. SICK therefore recommends using a flow monitor, e.g., a rotameter, to
monitor the calibration gas flow.
6.1.2.2
Connecting the gas
1
Remove the plug of the TRANSIC151LP gas inlet.
2
Fasten the reference gas tube to the gas inlet. Do not overtighten the inlet.
NOTE:
For adjustment in the process, fit an optional calibration gas inlet and
PTFE filter on the TRANSIC151LP.
●
Use a sufficiently high reference gas volume flow for optimum adjustment results.
●
With low reference gas volume flow, high adjustment precision is only achieved with
process gas flow rates near zero.
WARNING:
Escaping reference gas can enter the process
▸
Ensure the reference gas is compatible with the process gas.
NOTE:
Prevent contamination of the gas inlet
If reference gas is not connected:
▸
Use a plug for the optional gas inlet of the TRANSIC151LP.
This prevents dust or dirt depositing on the gas inlet.
NOTE:
Prevent process gas escaping!
If reference gas is not connected:
▸
Use a plug for the optional gas inlet.
Although the non-return valve prevents process gas from escaping, the plug on the
optional gas inlet of the TRANSIC151LP can also be used.