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Since I haven’t received comments, here are some things the experts involved in the PDCC might look at – to help guide you and limit the time you need to spend. I could use your thoughts. Generally, Ethernet-SPE requirements are specified for devices with 10BASE-T1L and optional power classes 10 to class 15 clause 104 power. Ethernet SPE is in section 6 of the document. Class 15 clause 104 power is 58V, 1579mA. The coupler mentioned in annex E appears to be clearly stated for connecting larger diameter cable (e.g., AWG18) to equipment cords with connectors only capable of small diameter (e.g., AWG22) wiring. I don’t
see this as an issue, if properly used. Table 17 Note 2 is the only mention of Annex E in the text, and Table 17 gives guidance for wire size in the field. If we need to focus comments, they should be on Table 17. I note that most of Table 17’s applications with > 750mA current (class 15 only) are 18 AWG or greater. The exception is or short distance (< 40m) connections which allow 23 and 22 AWG. I would suggest discussion
and consideration on a comment on the use of class 15 power with 23 & 22 AWG wiring, even on short links – that a reference here to TS 29129, where cabling heating & bundling is considered would be prudent. Table 17 indicates the interconnection module in Annex E is for connecting to the larger diameter field cable, and Annex E clearly states about the connector, that the cables in the field with power are <
AWG22 (larger diameter). Since the specification also allows screw terminals, which could ALSO be improperly used to connect small diameter wiring segments, I don’t see this as adding substantial risk. Perhaps a word of caution might be added to Table 17
as above, referring to TS29125, but I don’t see an issue with the interconnection module itself. There are some issues in the specification of 10BASE-T1L used that may require comment – for example, full compliance to clause 146 is not called out – it is piecewise. For example, 146.5 is missing – these
are PMA electrical specifications, kind of important, and called out in the conformance testing section, oddly but not actually required…. I’m in the process of auditing the PHY requirements to consider where there are exceptions. So far, only the duplicates
noted, grounding & isolation, and fault tolerance for PSEs. There are, however, others missing like PD fault tolerance is missing entirely. It seems that the conformance tests assume compliance (with some exceptions, like MDI fault tolerance in 6.1.3) but
the requirements aren’t here… There appears to be an error in 6.1.3 where it only changes the droop requirement for class 10 devices. 802.3 changes it for all devices where the MDI is also a PI, and I expect it would be independent of
class. There are also some duplicative requirements, for example, 6.3.3 (polarity sensitivity) is duplicative of the requirement in 104.5.2; and 6.3.5 seems in conflict with the amendment in 802.3dd to remove the
fault tolerance requirement from PSEs. Within 802.3dd we removed the fault tolerance requirement for MDIs that were also Type E PSE PIs and left it unspecified. They note that this requirement is changed, but we should consider the implication. I would very much appreciate that someone look at the grounding & isolation sections (6.3.2 & 6.3.4) – there is a pretty detailed description there that I haven’t had a chance to go through, and it relies
on IEC 61010, and doesn’t seem to include 802.3 isolation requirements. I’m trying to dig through the large quantity of phy stuff that popped up when I realized that general compliance to clause 146 didn’t seem to be required, and I’d appreciate someone else
taking a lead on grounding/isolation. We need a sanity check to 802.3 isolation assumptions, as the 61010 and specs in 6.3.4 seem different. Perhaps a reference to meeting 802.3 specs as well. George Zimmerman, Ph.D. President & Principal CME Consulting, Inc. Experts in Advanced PHYsical Communications 310-920-3860 To unsubscribe from the STDS-802-3-PDCC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-PDCC&A=1 |