Schneider Electric 890USE17700 manual Configuring Master Controllers, Field Name Description

STB NIP 2212 Web Server

Configuring Master Controllers

Introduction

Understanding

Processing

Mastery

Fields on the Master Controller Web Page

Any controller on the Ethernet network has the potential to become the master of an island on that network. Mastery can be obtained on a first-come/first-serve basis. The STB NIP 2212 allows you to pre-assign mastery to as many as three specific controllers on the network. If one of these assigned controllers is connected, it will take mastery over any unassigned controllers, even if an unassigned controller has connected to the island first. To assign one or more master controllers, use the Master Controller web page.

A controller that has mastery over an island has the ability to write to the island’s output process image and to change operating parameters on the island nodes.. Typically, the first controller to request write access is granted mastery. If another master attempts to write to the island while the first controller has mastery, the NIM sends an error message and access is denied.

If a master controller has been configured on the Master Controller web page (See Sample Master Controller Web Page, p. 78), a write request from it will pre-empt processing mastery from any other device during its reservation time.

To pre-assign one or more (up to three) master controllers for the STB NIP 2212, identify them by their IP addresses:

Field Name	Description
Master x ID*	The unique IP address (See How the STB NIP 2212 Obtains IP Parameters,
	p. 60) for a master controller.
reservation	The amount of time in ms allocated to a master controller for writing to the
time	STB NIP 2212. Other controllers attempting to write to the STB NIP 2212
	while the master is connected will receive an error message.
	The default reservation time is 60,000 (1 min). Each time the master writes to
	the NIM, the reservation time is reset to 60,000.
holdup time	The amount of time in ms that output modules will hold their current state
	without an update by a Modbus write command (See List of Supported
	Commands, p. 135). When the module hold-up time out expires, the outputs
	will be driven to their defined fallback states (See Island Fallback Scenarios,
	p. 161).
	Note: The holdup time must be defined via the Master Controller web page.
	Holdup time out parameters and values are stored in nonvolatile Flash
	memory.

*If you do not enter an IP address, then write access to the NIM will be obtained by the first master that writes to it.

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