Evening all.
Clarifier bridge, rotating, so no cable to it. 1734-AENTR with six modules out on the bridge, a pair of industrial wireless bridges back to the plant switch, CompactLogix 5069-L320ER in the building. RPI on the AENTR is 20 ms, left at default.
A few times an hour the rack drops with 16#0204 connection timed out, back within a second or two, and the scraper drive stops because its run permissive comes through that rack. Signal on the bridge's page sits at -55 to -60 dBm, which the radio vendor says is good.
We moved the antenna higher and then swapped to a bigger directional one, no change at all. What happens when a wifi link retries, does it drop everything for a moment? Do I need a different radio? Or is 20 ms just asking too much of a radio link?
What's the connection timeout on that rack. Not the RPI. The timeout.
Didn't know there was one separate from the RPI, maybe I've never looked properly. I can't see it on the Connection tab, just RPI 20 ms and the inhibit box.
It isn't on the tab. Timeout is RPI times a multiplier, 4 by default, so 80 ms. On a bridge here the access point's own log showed retries and roams of 100 to 200 ms every time the bridge swung past a section of steel handrail. Every one of those is longer than 80 ms, so the connection gets declared dead before the radio has finished retrying. Signal strength looks fine because it is fine, most of the time.