Teledyne 9110TH - Nitrogen Oxides Analyzer - Manual (Page 122)

Model 9110TH NOx Analyzer Operating Instructions
Teledyne Analytical Instruments 102
4.11.9. MULTIDROP RS-232 SET UP
When the RS-232 Multidrop option is installed, connection adjustments and
configuration through the menu system are required. This section provides instructions
for the internal connection adjustments, then for external connections, and ends with
instructions for menu-driven configuration.
Note that because the RS-232 Multidrop option uses both the RS232 and COM2 DB9
connectors on the analyzer’s rear panel to connect the chain of instruments, COM2 port
is no longer available for separate RS-232 or RS-485 operation.
CAUTION – Risk of Instrument Damage and Warranty Invalidation
Printed circuit assemblies (PCAs) are sensitive to electro-static discharges too small to be felt by
the human nervous system. Damage resulting from failure to use ESD protection when working
with electronic assemblies will void the instrument warranty. See A Primer on Electro-Static
Discharge section in this manual for more information on preventing ESD damage.
In each instrument with the Multidrop option there is a shunt which jumpers two pins on
the serial Multidrop and LVDS printed circuit assembly (PCA), as shown in Figure 4-8.
This shunt must be removed from all instruments except that designated as last in the
multidrop chain, which must remain terminated. This requires powering off and opening
each instrument and making the following adjustments:
1. With NO power to the instrument, remove its top cover and lay the rear panel open
for access to the multidrop PCA, which is seated on the CPU.
2. On the Multidrop/LVDS PCA’s JP2 connector, remove the shunt that jumpers Pins
21  22 as indicated in Figure 4-8. (Do this for all but the last instrument in the
chain where the shunt should remain at Pins 21  22).
3. Check that the following cable connections are made in all instruments (again refer
to Figure 4-8).
 J3 on the Multidrop/LVDS PCA to the CPU’s COM1 connector
(Note that the CPU’s COM2 connector is not used in Multidrop)
 J4 on the Multidrop/LVDS PCA to J12 on the motherboard
 J1 on the Multidrop/LVDS PCS to the front panel LCD