AB PLC5/10 programming connection

On a side note - does anyone know why the conductors of the Blue Hose cables were reversed when switching from DH+ to RIO ?


Was it just simply that you could tell what the cable was by looking at the terminations ??

Click to expand...

My memory is that was the reason - to make it easy to identify was it DH/DH+ or RIO. Then they screwed it up by rotating the connector 180 degrees on some products.

Let's be Clear until we're Blue in the face...

daba said:

...On a side note - does anyone know why the conductors of the Blue Hose cables were reversed when switching from DH+ to RIO ?


Was it just simply that you could tell what the cable was by looking at the terminations ??

Click to expand...

Mike_RH said:

My memory is that was the reason...

Click to expand...

Yes, it's as simple as that. Depending on the application environment and requirements, there are 10 or so officially recommended cable types for DH, DH+ and Remote I/O applications. For standard light industrial applications, up to 5000ft, 1770-CD Belden #9463 cable is recommended. As we know, it is often simply referred to as "Blue Hose" because of its Blue PVC jacket.

1770-CD Belden #9463 Blue Hose specifications:-

1 pair (Blue, Clear), (7 x 28) #20 AWG tinned copper, polyethylene insulation, Beldfoil + 55% tinned copper braid and drain wire, Blue PVC jacket. Nominal diameter 0.243 inch.

I'm part quoting the specs for the standard Blue Hose cable for nostalgic reasons but also to make it abundantly "clear" that because this cable is simply a "1 pair" cable, both cores (Blue & Clear) are identical in all but insulation colour. So it is of course perfectly OK, from an electrical signal point of view, to wire this pair either way. As long as the correct signal polarity is adhered to, for whichever communications protocol is being used, it will work. It may even work, to some degree, where the pair and/or the shield have been mixed up.

The good practice wiring guidelines for Data Highway Plus (DH+) and Remote I/O (RIO) advise us to physically differentiate between these two networks by using a particular wiring convention:-

Data Highway Plus

1. Clear
__Shield
2. Blue

Remote I/O

1. Blue
__Shield
2. Clear

That is, the difference in the wiring is purely implemented so as to physically differentiate which network is being used.

Regards,
George