Connecting A-D converters
On modern Macs, which have USB ports, you need a USB --> serial converter. I've verified that the Keyspan (now, TrippLite) USA-19HS works nicely. I've also verified that other converters DO NOT work reliably, so I highly recommend the Keyspan/Tripp Lite units. Make sure the driver software is appropriate for whatever version of OS X you are running. Here are some connection considerations for the various supported A-D converters (more details on these devices are here).
Sable Systems Universal Interface 'UI2':
Connecting the UI2 is simple. With your USB-serial converter installed (with the necessary driver software), you should not have to do anything except plug in the cable that comes with the UI2.
Data Electronics DataTakers:
These instructions refer to the basic DT50/500/600 (referred to below as 'DT500') and DT800
models. Earlier models may not work, and I have not had the opportunity to test other versions. However, users have told me that other DataTaker models do work with the software.
- The software expects the default factory settings (no parity, 8 data bits, 1 stop bit). For the DT500, the standard baud rate is 4800. For the DT800, a faster rate will be automatically used, up to 115,000 baud (if necessary, the maximum rate can be adjusted from within the LabHelper A-D menu). If you want
to use other baud rates on the DT500, set the appropriate DataTaker switches for the desired
rate. Make sure to use no parity, 8 data bits, and 1 stop bit (If
these settings are incorrect, the software won't work).
- Build (or purchase) a connecting cable and power supply, as outlined
in the very detailed and helpful DataTaker instruction manual.
- To drive external devices with a DataTaker's digital outputs, you may have to build a simple circuit to supply the necessary positive voltages.
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Advantech ADAM-4019:
The ADAM 4019 is a simple, inexpensive A to D converter. I has 8 quite versatile channels (each can be a voltage or thermocouple input). However, it isn't very fast (about 10 samples/second total) and it has no digital or voltage outputs, so you can't control external devices with it (you can ad digital outputs by adding an ADAM 4050, and another 8 A-D channels by adding another ADAM 4019 or 4017).
- The software expects the default factory settings (no parity, 8 data bits, 1 stop bit). For the DT500, the standard baud rate is 9600. A faster rate will be automatically used, up to 115,000 baud (if necessary, the maximum rate can be adjusted from within the LabHelper A-D menu). Note that the ADAM units use the RS-485 protocol, so you'll need an RS-232 to RS-485 converter to use it with the TrippLite USA-19HS. Make sure to use no parity, 8 data bits, and 1 stop bit (If
these settings are incorrect, the software won't work).
- Build (or purchase) a connecting cable and power supply, as outlined
in the instruction manual. Note that the ADAM units use the RS-485 protocol, so you'll need an RS-232 to RS-485 converter to use it with the TrippLite USA-19HS.
- To drive external devices with a 4050's digital outputs, you may have to build a simple circuit to supply the necessary positive voltages.
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Remote Measurement Systems ADC-1:
NOTE: the ADC-1 is no longer being manufactured, but used ones can be obtained and work fine for many purposes.
ADC-1s are slow, but have 16 analog inputs. If possible, get one with the normal
input voltage range (±0.42 volts) and the 50X programmable
gain option on all 16 channels. You can use an ADC-1 with the
gain option on only 8 channels if you are careful to attach your instruments
to those channels exclusively. You can even use an ADC-1 without
programmable gain, but resolution will be much more limited.
- Set the DIP switches on the back of the ADC-1 to 9600 baud (you can
use slower baud rates, but the default is 9600), no parity, 8 data bits,
1 stop bit. If these settings are incorrect, the LabHelper software
won't work.
- Build a connecting cable and power supply, as outlined in the very
detailed and helpful ADC-1 instruction manual.
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