calculation on devicenet

hello there !!!!!!

yes its me again

i have a new doubt, im already lookin for but for security lol.

how can i calculate the current on a devicenet network???

im using networks of LM10 maximum of 56. is there any formula??

or just #nodes * current of LM10 = total current???

obiously long of the cable affects, how???

best regards roger

I presume that an "LM10" is a GE Industrial Motor Overload Relay.

Yes, the basic idea behind DeviceNet power consumption is simply to add all the power-consuming devices on the network and use that value to size your cable (many thin cables only support 3 or 4 A) and your power supply.

I did not find in the LM10 User Manual how much power it consumes on the DeviceNet port.

There are a handful of other rulse you must adhere to as well for a successful DeviceNet, including the Trunk Length, the Dropline Length, the Dropline Budget, and Common Mode Voltage Drop.

A good publication that covers all of these things is the Rockwell Automation Publication DNET-UM072, DeviceNet Media Planning and Installation Guide.

I presume that an "LM10" is a GE Industrial Motor Overload Relay.

lol yes it is. i forgot to tell you, sorry

by the way the manual is excelent thanks, its disipate some doubts.

one more question,

im doing a network, with 4 sacqdnet(modicon scanners)
and 9 LM10 (GE Industrial Motor Overload Relay)

the network doesnot have problems, its workin fine, but my boss tellme that put 25 meters of thin cable to increase the length of network, but when try o upload again i lose all the devices, except sacqdnet cuse theyre before the 25 meters,
isnt thin cable supports 100 meters??
or maybe is taken as drop??? (for drop rule of 6meters)

best regards roger

The "trunk line" is determined only by the placement of the termination resistors.

If you have a working system and add 25 meters of cable to it but leave the termination resistors in their original positions, then the 25 meters of cable is a "drop line".

This is much longer than the drop line limit of 6 meters.

What you probably need to do is move the termination resistor to the end of the 25 meter addition, which will make the addition into part of the "trunk line".