DH+ minimum distance between each node?

[ckchew666]

Hi,

Can anyone please confirm this. I remember i read somewhere sometime ago that the distance between each node in the DH+ network must have a minimum distance. Correct me if I'm wrong.

Thanks.

 

[Lancie1]

I have never heard that. I have seen nodes right next to each other, about 18" run. On the other hand, there is a maximum distance.

 

[Ken Roach]

Although I have successfully used DH+ with very short distances, I remember a rule of thumb to allow 10 feet of cable minimum between nodes. I recall putting in "service loops" of cable inside cabinets that had both a PLC-5 and a PanelView for this reason.

I can probably find this in my DH+/DHII/DH485 cabling manual at the office tomorrow.

 

[Oakley]

Ken is correct - the recommended minimum distance is 10 feet. In our production system, we follow that rule. In our test environment, we don't. It still works.

 

[TimeFluxCap]

That is an interesting post. I had a problem trying to setup a station connector with a RS232 port on it mount next to a PV+ with DH+. DH+ cable from PV+ node to SC was only about 500mm

 

[Operaghost]

Yeah, I don't know where this 10 foot minimum is coming from. I just browsed through the DH+ manual and nowhere can I find anything saying what the minimum distance between nodes should be.

Granted it does mention REPEATEDLY that drops should be 10-100ft. Does this also somehow apply to the trunk segments or daisy-chain connections? Or did I just miss a section of the book?

OG

 

[Contr_Conn]

I can confirm also: 10ft is a minimum for DH+ and RIO.
Something related to the signal wave length and reflection.
Don't have a document now, but can confirm tomorrow.

Here is KB: G2683: Installation Guidelines for twin axial cable.

 

[ckchew666]

Thx for all the feedback & sorry for the reply, I'm out from office for quite some time.

Alright, I've also checkout this question with Rockwell, their reply is recommended to have 10 feet minimum distance for the drop line.

But I taught DH+ is a daisy chain network, which is trunk line and which is drop line? If ControlNet there is a dropline & trunkline, right?

Thx.