B&B Electronics Strain Gauge/Load Cell Bridge Amplifier FBDA - Manual (Page 5)

Documentation Number FBDA0797 Manual 3
B&B Electronics -- PO Box 1040 -- Ottawa, IL 61350
PH (815) 433-5100 -- FAX (815) 433-5105
Chapter 2: Connections
Power Supply Connections
The FBDA module requires 13 to 18VDC @ 10mA. Model
232PS2 available from B&B Electronics is recommended. Although
the 232PS2 is a 12VDC power supply, it outputs a voltage above
13VDC when less than 10mA are being drawn from it. The power
supply is connected to the terminal blocks marked +13V and GND.
Make sure the polarity of the power supply is correct (the white
striped wire on the 232PS2 is the positive lead).
Sensor Connections
Most full-bridge sensor circuits require four connections for the
sensor to operate properly. These connections will be made using
the terminal blocks. First, an excitation voltage is required to excite
the bridge circuitry. This can be done using the adjustable excitation
voltage (marked EXV) available on the FBDA, or another voltage
source can be furnished by the user. This excitation voltage is
referenced with respect to ground, which is the second connection
(marked GND). The remaining two leads from the sensor carry the
differential signal voltage that is to be conditioned and read by the
data acquisition module. These two leads are connected to SIG+
and SIG-. Consult your sensor manual to determine the signal lead
polarity. Table 2.1 shows the terminal block assignments.
Note: A/D 1 is connected straight through from the terminal blocks
to DB-25 pin # 9. This allows access to A/D channel 1 on B&B
Electronic’s SDAXX line of A/D converters. This channel can read
voltages between 0 and 5VDC (useful for calibrating the excitation
voltage). This channel has no signal conditioning circuitry. It is
simply connected to A/D 1 on the data acquisition module.
Table 2.1: Terminal Block Assignments
Terminal
Block Name
Function I/O
SIG+ Positive Signal Lead Input
SIG- Negative Signal Lead Input
EXV Excitation Voltage Output
A/D 1 A/D Converter channel Input
+13V Power Supply Connection Input
GND Power Supply Connection Input