Measurement Computing CIO-DAC08 - Manual (Page 16)

Chapter 4
Functional Details
Signal connections
Each of the CIO-DAC08 outputs are individually buffered through an OP07 operational amplifier (OP-AMP).
The OP07s are socketed so that if one fails it can be replaced in the field. The OP07 for each channel is located
just below the calibration potentiometers for that channel.
At the full rated output swing of ±10V, each channel is capable of sinking or sourcing ±5 mA. That means a
load of 2K Ohms can be connected to each channel.
As the load resistance is raised from 2 K up to 10 MΩ or more, the output load on the DAC decreases. Any
load resistance greater than 2K is fine.
As the load resistance decreases, the output load increases. The OP07 responds by producing a lower output
voltage. If your CIO-DAC08 will not produce the output voltage specified by the code & range combination, it
is a good idea to check the load with an ohm meter.
Under normal circumstances you will not damage the OP07 by connecting the output to ground. If your
connection results in a failure of the OP07, chances are good that there was some potential at the connecting
point in addition to a load at ground or between 0 and 2 K Ω. Explore the point with a DVM before
reconnecting the CIO-DAC08 (and after replacing the OP07 of course). Connect the negative lead of the DVM
to any LLGND pin of the CIO-DAC08.
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