Allen-Bradley 1734-ADN Manual de usuario descargar pdf (Pagina 153)

1 Publication DNET-UM004A-EN-P - March 2004

Chapter

Tune the Performance of a DeviceNet

Network

Using This Chapter

This chapter shows how to improve the performance of your

network. As you configure and program your network, use the default

settings whenever possible. Once your network is running, determine

if you need to improve performance.

To improve the performance of your network, consider the following:

If: Then:

a specific device requires a faster update Change the I/O parameters of the device to change of state

(COS).

an analog device either:

• changes slower than the scan cycle

• requires a repeatable update period (e.g., for PID calculations)

Change the I/O parameters of the device to cyclic.

multiple devices are:

• input only

– and –

• I/O parameters are currently set to polled with an input size

≤ 8bytes

For each of those devices, change their I/O parameters to

strobed.

2 or more devices send or receive large amounts of data (e.g.,

PanelView operator terminal)

1. For each of those devices, set their I/O parameters to

polled with a poll rate = background.

2. For the scanner, set the poll ratio = 2. Increase the poll

ratio if needed.

communication intermittently stops (status code 78) with a device that:

• sends or receives large amounts of data (e.g., PanelView

operator terminal)

– and –

• has the I/O parameters currently set to polled

Increase the interscan delay.

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Allen-Bradley 1734-ADN Manual de usuario Pagina 153