Teledyne T703, T703U 5.3. MULTIDROP RS-232 SET UP

Teledyne API T703/T703U Calibrator Operation Manual Communications
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5.3. 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 instrument’s rear panel to connect the chain of instruments, COM2
port is no longer available for separate RS-232 or 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 5-3.
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 5-3. (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 5-3):
 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
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.
07223C DCN6572