GDU
27-1500
Original Instructions
14
9901X0265 Issue 2
3
ANALOGUE INPUT MODULE WITH TRANSDUCER EXCITATION
3.1
General Description
The Analogue Input Module is a general purpose input scanner capable of accepting
up to 8 separate signal sources.
It has the part number 1914B0046 or 27-1505.
The input signals can range from +/-10 volts full scale when used with a system gain of
1, to +/-9.76 m.volts full scale when used with a system gain of 1024. The input
channels are connected to the system analogue to digital conversion module by an 8
channel 2 pole solid state multiplexer.
The module features a 10 volt stabilised power supply
for transducer excitation, thus simplifying the tasks of
connecting many types of sensor, and has input
overvoltage protection to prevent system damage in
the event of incorrect connections being made.
The module has built-in gain, offset circuitry and a 16
bit ADC. On the front of the module are 9 status
LEDs.
The top left LED indicates the module has been
correctly recognised by the CPU. The other vertical 8
LEDs down the centre of the module indicate the
channel selection status. These LEDs are on when a
particular channel has been ‘SET’.
The top LED is for channel 1, going down to the
channel 8 LED at the bottom.
3.2
Specification
Number of input channels
8 Differential
Signal Range
+/-10 Volts Full Scale (x1 system gain) to
+/-9.76mV Full Scale (x1024 system gain)
Cross Talk Immunity @ DC
120 dB
Cross Talk Immunity @ 10 kHz
80 dB
Leakage Current
10 nA
Transducer Supply
10 Volts +/-10 mV
Stability
50 ppm/
o
C
Maximum current per module
500 mA
Maximum Input Voltage
± 14 Volts
