Field Networks FAQ


Frequently asked questions and answers for Field Networks - Industrial Automation


Cable Length Used in DeviceNet Network


Question

What cable lengths are sold for the cables used to wire the network between DeviceNet Master Units and DeviceNet Slaves?


Answer

There are two kinds of DeviceNet Cable: DCA2-5C10 (Thick Cable) and DCN1-5C10 (Thin Cable). These Cables are sold in 100-m increments.


CompoBus/S Network: Combination of SRT1 & SRT2 Slaves


Question

Is it acceptable to combine SRT1 Slaves and SRT2 Slaves in a CompoBus/S system?


Answer

These Slaves can be combined, but only when the high-speed communications mode is used. They cannot be combined when long-distance mode is being used.


The two kinds of Slaves cannot be combined in long distance mode because the SRT2-series Slaves can be switched between long-distance mode and high-speed mode, but the SRT1-series Slaves support only high-speed mode.


Difference between T-branch Tap and a Terminal Block Style Terminating Resistor


Question

What is the difference between methods to use a terminating resistor attached to the T-branch Tap or a Terminal Block style terminating resistor of the DeviceNet?


Answer

It differs by whether the T-branch Tap "DCN1-1C" and/or "DCN1-3C" is located within 6m or more than 6m far from a node of the main line.


If it is located within 6m from a node of the main line, a supplied terminating resistor can be attached to the T-branch Tap.


If it is located more than 6m far from a node of the main line, a terminating resistor must be attached to the end of the node.


In this case, the T-branch Tap fitted with a terminating resistor or the Terminal Block style terminating resistor DRST-1 must be connected. The maximum cable length between the node and the terminating resistor is 1m.