Physics:piner (07/25/82)
In response to Leonard@sri-unix's request for info. here is what I know. I have a A/D board from Tecmar which has functioned with out any problems for a couple of years now. The board I have runs 8 dual inputs, or 16 single, has a 10 microsecond conversion time, and 12 bit accuracy. The zero is very solid, almost no drift. I got an S-100 bus made by HUH with the board so I could hook it up to my TRS-80. The HUH S-100 to TRS-80 bus board (with power supply, box, fan, etc.) works well, and has four slots. So I can add three other S-100 boards to the TRS-80 if I ever need to. I am now using the A/D board with an LNW-80 at the higher clock speed of 4MHz. The only trouble I had when I switched computers from TRS-80 to LNW80 was with the cable connecting the HUH to the computer. I had to shorten it from 5 feet to about 3 feet. Everyone says it should be less than one foot, but I have had no problems with a 3 foot cable. For more info. I suggest you call Tecmar and tell them what you want and get current information. Mine is a little out of date. Their phone number is 216-464-7410. They have an add in this month's issue of Byte too. I think they also make a Apple version of some of their boards. They make more expensive A/D boards (about $1000) which have amplifiers built in, and have 16 bit accuracy. The best reason for using a LNW80 I have found is the 480x192 pixel display lets you plot the data as you take it. This can be a big help. The Tecmar board is on the whole a very good board and it works well with the TRS80 or LNW80, but even when life is a bowl of cherries, you have to watch out for pits. In this case, the problem is with using the real time clock. If you use the computer's real time clock, you can not do I/O which disables interupts! So if you are timing your measurements you can not write the results to disk or tape! I am working on a way around this limitation, but have not yet settled on a solution. If anyone else out there in net land has beat this problem, let us know the solution. Richard Piner Physics, Purdue