7EN02-0290-11

Distributed Numeric Module

The Distributed Numeric module allows you to automatically transfer data from a Virtual Processor to another ION node such as an IED or different Virtual Processor. This module is only available in the VIP.

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Overview

When the Distributed Numeric module is enabled, the numeric value present at the Source input is written to the ION node you have specified. The module continuously monitors the Source input value. If the Source changes by an amount exceeding the value defined in the Update Threshold setup register, the new value will immediately be copied to the address defined in the Destination node.

NOTE: It is highly recommended that you use a Data Monitor module in conjunction with this module. See the Data Monitor module description for an example.

If the Source input value is stable, i.e. within the limits defined by Update Threshold, then the Destination node will be refreshed at a regular interval (this interval is defined by the Refresh Time setup register). When used in conjunction with the other Arithmetic and External Control modules, the Distributed Numeric module becomes a powerful tool for automated plant-wide demand or power factor control, including load shedding and start-up of auxiliary power.

Inputs

Source

All Distributed Numeric modules have one Source input. The numeric value at this input is written to the node address you specify in the Destination setup register.

Activate

This input allows you to manually activate or deactivate the Distributed Numeric module. By linking the Status output of a Data Monitor module to this input, the Distributed Numeric module will be automatically disabled if the data at the Source input becomes out-of-date, thus preventing a control action based on old data. Linking this input is mandatory.

NOTE: The WriteNow input is automatically disabled when the value at the Activate input is off.

WriteNow

Linking this input to a pulse/trigger Source forces the module to operate in pulse-driven mode, that is, the module will only write to the Destination register when it detects a pulse at this input.

If this input is not used (not linked), the module writes whenever the Source input changes by an amount exceeding the value defined in the Update Threshold setup register, as well as at regular intervals (as specified in the module’s Refresh Time setup register).

Setup registers

Destination

This register allows you to specify a node and register to where the value at the Source input will be written. This register displays the available nodes, module managers, modules and output registers from which you can select. Typically, you will select the output register of an External Numeric module.

Update Threshold

This numeric bounded register specifies a deadband for the Source input. When the Source input changes by an amount exceeding the Update Threshold value, the Destination node is updated with the new value.

NOTE: If the WriteNow input is linked, then the Update Threshold and Refresh Time setup registers are not used.

In the illustration below, time zero indicates the current value appearing at the Source input.

“X” indicates the times when the module updates and overwrites the current value. This happens whenever the last written value increases or decreases by an amount greater than the specified threshold value.

Refresh Time

This register specifies how frequently the node is updated with a new Source input value. Specifying a value of zero in this register disables the Refresh Time feature.

EvPriority (event priority)

This register allows you to assign priority levels to specific event conditions.

Output registers

Status

An on state indicates the normal working condition. An off state indicates timeouts, communication errors, or other failures that may occur at that instant when the module is trying to write to the destination address. A not available value indicates that either the module’s Activate input is not linked, or it has an off value.

Initiate Write

This output will generate a pulse when the Distributed Numeric module sends its Source input value to the address specified in the Destination setup register.

Acknowledge

This output will generate a pulse after a successful write, i.e. when the Distributed Numeric module receives an acknowledgement from the device specified in the Destination setup register.

Time to Update

This numeric output register reports the time (in seconds) between an Initiate Write pulse and the resulting Acknowledge pulse.

Event

This output register is used to record the module’s successful and/or unsuccessful attempts in writing to the Destination register.

Event priority group Priority Description
Setup Change 10 Input links, setup registers or labels have changed.
Source Value Change * Write initiated (send the message).
Source Value Change * Write overwritten (Source changed before the last write got through. Resend with a new value and discard previous attempt).
Write Succeeded * Write complete and the destination has been updated.

Write Failed

Write Timeout

Got Comm Error

Got Invalid Node

* Write did not complete and destination was not changed.
* The priority of these events is determined by the value in the EvPriority setup register.

The Event output register stores the following information for each ION event: time stamp, priority, cause, effect, and any values or conditions associated with the cause and effect.

Detailed module operation

When the Distributed Numeric module is activated, the numeric value appearing at the Source input is written to the register specified by the Destination setup register. The Update Threshold setup register determines by what amount the current value must change before a new value is written. For example, if the Update Threshold is set to 5, and the current value at the Source input is 100, the module will write the new value if the Source value drops below 95 or rises above 105.

When this module is activated and the Source input receives a new value that is below or above the limits defined by the Update Threshold value, the Distributed Numeric module automatically writes this new value to the register specified in the Destination setup register. If the value at the Source input is stable or within the threshold limit you specified, the module periodically updates the value at the rate you specify in the Refresh Time register. This ensures that the value at the output register is always accurate and current.

If the Write Now input is linked, the Update Threshold and Refresh Time setup registers have no effect on the module, and the module only updates the Destination setup register when a pulse is detected at the WriteNow input.

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