---
title: "system.opchda.readProcessed"
description: "Reads processed values from the OPC-HDA server."
---

# system.opchda.readProcessed

> Reads processed values from the OPC-HDA server.

This function is used in **Python Scripting**.

## Description
Reads processed values from the OPC-HDA server. Processed values are calculated values, based on the aggregate function requested for each item. The list of aggregates can be obtained by calling [system.opchda.getAggregates()](appendix\scripting-functions\system-opchda\system-opchda-getAggregates.md).

## Client Permission Restrictions
This scripting function has no [Client Permission](../../../ignition-modules/vision/vision-project-properties/vision-project-properties.md#vision-permissions-properties) restrictions.

## Syntax
`system.opchda.readProcessed(serverName, itemIds, startDate, endDate, resampleIntervalMS, aggregates)`

### Parameters
Type | Parameter | Description 
------- | ------- | ------
String| `serverName` | The name of the defined OPC-HDA server to read.
List[String]| `itemIds` | A list of item ids to read.
Any| `startDate` | The starting date/time of the query.
Any| `endDate` | The ending date/time of the query.
Integer| `resampleIntervalMS` | The interval, in milliseconds, that each value should cover.
List[Integer]| `aggregates` | A list which should be one-to-one with the item ids requested, specifying the integer id of the aggregation function to use. The aggregation ids are defined in the OPC-HDA specification. The list of aggregates can also be obtained by calling [system.opchda.getAggregates()](appendix\scripting-functions\system-opchda\system-opchda-getAggregates.md).

### Returns
**List[ReadResults]** - A list of read results which is one-to-one with the item IDs passed in. The ReadResult object has a 'serviceResult' quality property that indicates whether the call was successful, and is itself a list of QualifiedValues.

### Scope
Gateway, Vision Client, Perspective Session

## Code Examples
```python title="Example #1"
# This example will read processed data from a Matrikon server between two specified dates.
# Declare start and end dates
start = system.date.getDate(2022, 3, 14)
end = system.date.now()
 
# Call system function and print results
readValue = system.opchda.readProcessed("Matrikon",[1],start,end,1000,[1])
print readValue
```