Chapter 1: Functional Description
Manual Number: 00650-014-4
Page 1-3
Enhancements
Capabilities of the AD12-8 can be greatly enhanced by use of one or more of the following hard-
ware devices or software packages:
a. UTB Screw Terminal Cards.
This terminal board allow direct input/output signal connections via screw terminals. The card
also provides a breadboard area with ±12V and +5V computer power. This breadboard area
can be used for amplifiers, filters, and other user-assembled circuits.
b. AT16-P Expansion Multiplexer and Instrumentation Amplifier
The AT16-P is a 16-channel amplifier/multiplexer that features differential or single-ended
input capability and a choice of either DIP switch selectable gains or software programmable
gains. The AT16-P allows multiplexing of 16 analog input signals to a single AD12-8 analog
input channel. As described earlier, up to eight AT16-Ps can be connected to a single AD12-
8 to provide input capability for up to 128 analog inputs.
The AT16-P includes a low-drift instrumentation amplifier with DIP switch selectable gains of
0.5, 1, 2, 5, 10, 25, 50, 100, 200, 500, and 1000. In addition, these gains can be software
programmed to provide individual gains on a channel-by-channel basis.
For thermocouple measurements, a cold junction sensor is provided to allow reference junction
compensation, via software, for thermocouple inputs. The reference junction output may be
assigned to channel 0 of the AT16-P or, alternatively, may be jumpered to an unused AD12-8
input channel. Open-thermocouple or break detect circuitry is provided.
The AT16-P may also be used with 3-wire RTDs, strain gages, and 4-20mA current transmitter
inputs. In this latter case, an application-specific version, the AT16I-P, is available.
c. LVDT8-P Multiplexer and Interface Card
This card provides AC excitation and signal conditioning to eight independent LVDT
transducers. As many as eight LVDT8-Ps may be connected to an AD12-8 to accommodate
up to 64 transducers.
d. SSH-04/-08 Simultaneous Sample and Hold Card
These cards install external to the computer and contain four and eight identical sample and
hold circuits respectively. Each circuit consists of a differential-input, programmable-gain
amplifier and a sample and hold amplifier. Outputs of the sample and hold amplifiers are
coupled through a multiplexer and a common buffer amplifier.
