Yokogawa Extractive Oxygen Gas Analyzer TDLS220 - Manual (Page 46)

<6 BASIC OPERATION> 6-16
IM 11Y01B02-01E-A 4th Edition September 11, 2012-00
6.4 Stream Switching & Valve Control Outputs
The TDLS220 has three valve drivers (24VDC each @ 12W max each) terminated at
TB-3. These can be used for either calibration/Validation and/or stream switching
functions. If using these valve drivers for any type of Calibration/Validation function
then please refer to the appropriate section of Instruction Manual. As shown in the fol-
lowing drawing, 3 process streams are connected to 3 gas valves then to the inlet of
the TDLS220 flow cell. The gas valves are controlled by three 24V relay output signals
from the launch unit of the analyzer. During normal operation, only one valve can be
open at a time. The connected solenoid wires at TB-3 may require the installation of a
ferrite coil to eliminate noise spikes – this is totally dependant on the site specific elec-
trical grounding conditions. If the analyzer appears to be re-booting when one or more
of the solenoids is activated then this means some noise protection is required. Either
add a ferrite coil to the connecting wires (contact Yokogawa for further assistance if
necessary) or add a 3A 50V directional diode across the +/- terminals at TB-3.
Valve 1
Valve 2
Valve 3
Stream 1
Stream 2
Stream 3
Inlet
Outlet
TDLS220 Sample Flow Cell
24V relay control signals
from Control Unit
Figure 15 - Valve Control
Figure 15- Typical Stream Switching Scheme