VTI Instruments EX1629 - Page 61

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EX1629 Basic Operation 61
TEDS
COMM
External customer
shunt cal
resistor terminals
Internal
Rcal
55K
-R Cal
+R Cal
Pin 5
Pin 4
TEDS
Device
(i.e. DS2430
or DS2431)
Strain
Bridge
8-pin telcom
connector (RJ-45)
350
120
User
10K
10K
+ Excitation
- Excitation
Quarter-Bridge
(1 of 48 channels)
+Excitation
+Sense
-Sense
+Excitation Sense
-Excitation Sense
-Excitation
+Excitation Sense
-Excitation Sense
RJ-45 Pin#
12345678
Pin 2
Pin 7
Pin 6
Pin 3
Pin 8
Pin 1
IO
GND
10K
10K
Instrumentation
Amplifier
+
-
x1
x10
x100
Hi
Lo
Shield
150
150
-Sense
-Cal
AGND
+Sense
Wagner
+Cal
AGND
430 kHz
LOW-PASS
FILTER
60.3 kHz
LOW-PASS
FILTER
ADC
TRIFILAR
FILTER
FIGURE 3-12: TEDS WIRING SCHEMATIC
NOTE Wiring the TEDS device to the EX1629 may not be as expected given the signal names used. The
correct wiring is provided above in Figure 3-12 as well as below:
RJ-45 Pin 4 (RCAL + / TEDS +) to DS2430/1 GND
RJ-45 Pin 5 (RCAL - / TEDS -) to DS2430/1 IO
The “+” and “-” indicators for the signal names indicate that, since negative voltages are used to
communicate with the TEDS device, the GND signal is actually more positive than the IO signal.