Teledyne API T703/T703U Calibrator Operation Manual Communications
107
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.
For more information on preventing ESD damage see A Primer on Electro-Static
Discharge; the manual can be downloaded from our website at http://www.teledyne-
api.com under Help Center > Product Manuals in the Special Manuals section.
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