Multidrop Rs-232 Set Up - Teledyne T101 Operation Manual

Operating Instructions

4.7.8. MULTIDROP RS-232 SET UP

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
Printed Circuit Assemblies (PCAs) are sensitive to electro-static discharges too small to be felt by the
human nervous system. Failure to use ESD protection when working with electronic assemblies will void
the instrument warranty. Refer to Section 13 for more information on preventing ESD damage.
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After connecting a USB cable between your PC and the instrument, ensure their baud
rates match (change the baud rate setting for either your PC's software or the instrument).
The baud rate setting is in the Communications Menu under COM2, which is the default
setup menu for USB configuration.
Also, while there are various communication modes available (Table 4-18), the default
settings are recommended for USB, except to change the baud rate if required..
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.
RS-485 operation.
In each instrument with the Multidrop option there is a shunt jumpering two pins on the
serial Multidrop and LVDS printed circuit assembly (PCA), as shown in Figure 4-9. 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/LVDS 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 4-9. (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 4-9):
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
•
Teledyne ML – T101 Operation Manual
NOTE
CAUTION