Hard to tell on the reading error part. But I was reading the DS2438 data sheet, and noticed that there is a A version that doesn't support the 'sleep' mode. I happened to have some samples of those, so I replaced the DS2438 in that sensor. I looked for a bit with the OneWireViewer, and didn't see any sags, so now I've gone back to my wserver s/w and will see what happens.
On my cable, I'm using cat 5, but using one wire from each pair, rather than a single twisted pair. Less common mode rejection, but less capacitance, which I wanted, given the distance.
(** Update: Just after I posted this, I looked at the s/w and noticed a low voltage error again. However, this time, when I monitored the VDD A/D input, although it did detect a low voltage, it had gone back to normal. So after 1 error, the DS2438 went back to normal operation. Maybe the sleep mode was somehow being triggered by environmental factors. In any event, if this solves it, I will switch out all my DS2438s with the A version. I sure hope this is the answer..... I can live with an occasional error, but can't put up with a locked up situation)
On my cable, I'm using cat 5, but using one wire from each pair, rather than a single twisted pair. Less common mode rejection, but less capacitance, which I wanted, given the distance.
(** Update: Just after I posted this, I looked at the s/w and noticed a low voltage error again. However, this time, when I monitored the VDD A/D input, although it did detect a low voltage, it had gone back to normal. So after 1 error, the DS2438 went back to normal operation. Maybe the sleep mode was somehow being triggered by environmental factors. In any event, if this solves it, I will switch out all my DS2438s with the A version. I sure hope this is the answer..... I can live with an occasional error, but can't put up with a locked up situation)