Yes danw2 there are JBs on the walkway to each tank. 1 2 pair cable goes to the tank side monitor. One pair to the tank and one pair back (this second pair gets terminated in the box and from here goes on to the next JB.
Thanks for the follow up, I had no time today but hopefully tomorrow to...
I might be writing in circles at times in my posts. Seems I am always pinched for time when I respond. Thanks VE1BLL for the input, I've been asking around the last couple of days and I'll be getting a scope tomorrow for testing.
DanW2, I fairly new to 485 installations and may be incorrectly...
Wow, again thanks for the replies. Before I get ahead of myself I'll provide more details.
The actual engineered install that we wired to called for a single twisted pair (2 wire) that went to the high side of 3 phoenix contact repeaters. From there each repeater had about 3 devices on it in...
Thanks much for the replies. I took a look through these application notes and still confused about which grounding configuration I should use. Chances are I'm still getting noise. This has been my biggest problem with the troubleshooting, in all my reading I have yet to see a solid explanation...
Thanks for the replies. Yes Dip switch settings are all good and we can actually see all of the devices on the daisy chain just fine, but only with a 75% or so reliability.(monitoring feedback bit at the master read/write block). Cable length fine and no errors on PLC / converter.
We were...
We are commissioning a tank level radar project and we are having some intermittent modbus failures (no slave response) when we poll more than one device on the loop. We can talk perfectly to each individual device if only polling that one device but when we try to talk to all 5 devices on the...
Thanks for the replies. More info that might help is that the protocol is RS485 and that as stated before there are only 3 devices in each loop that are being affected. (our installation consists of 2 separate loops, each with a total of 8 devices). They both come in to a multi-port DIGI card...
All,
We recently installed a number of radar level gauges and we have the problem of ~3 units per loop (7-8 devices per loop) intermittantly dropping communication for short periods of time. They are placed in a sort of 'star' setup, and they come through a DIGI card at our input. Feel there is...
