Manual

Innotech Device Network Cabling Installation Instructions

Chapter 2 – Primary Networks

Page 19

2-2 Management of other devices on the Primary Network

When other controllers such as Viewports or converters are added to the primary network they must

be installed in a manner that does not interrupt the integrity of the primary network. A lot of current

devices will have the so earth option and are fully isolated from the factory. There is no issue mixing

the current style earth connection with previous models of hardware on the primary network if the

following rules are applied.

These HMIs and converters will be referred to as so earth devices with respect to comms screen

termination.

For any so earth type device connected to a primary network there are some general rules for

connection.

• Do not break the continuity of the screen

• Use the ‘S1’ terminal for both the entering and leaving screen termination

• You must earth the system at a single bonded earth point. This is regardless of the number of so

earth points connected

• Attempt to ensure the net and global networks are the same length and follow the same path

2-2.1 HMIs and Converters

Typically all converters or HMIs will connect to the NET network and do not connect to the Global

network. This will present a few variations in how this device could be connected to the network. It is

important to ensure that the screen is kept continuous.

The below connection is wrong because it breaks the continuity of the screen creating a situation

where potential dierences in earth current between Device 1 and Device 2 can occur, therefore the

reliability of the comms connection may be compromised.





In the correct example, notice that the NET comms screen is in ‘S1’ terminal only. If you were to

use the ‘S1’ and ‘S2’ terminals you would break the continuity of the NET screen. This could cause

a potential dierence between each side of the HMI or converter and possibly introduce network

reliability issues.

The HMI or converter must have the Earth terminal or the 24V neutral, connected to earth where

available. This will provide the path for the so earth.

DeviceDevice

HMI / ConV

Figure 2-3: Incorrect HMI or Converter Comms Connection

Figure 2-4: Correct HMI or Converter Comms Connection