32EVR1500 Installer/User Guide

3.Click the Enabled checkbox to enable the calculation.

NOTE: An enabled calculation is available for use in the following operations: SNMP actions,

Output actions, Thresholds, Rules, Timed Rules and Reports.

4.Type a unique name for the calculation in the Unique name field. The name cannot contain any spaces. The only special character allowed is the underscore (_).

5.Type the equation for the calculation in the Calculation field using the format shown in the following example:

Temp_average=($temp1+$temp2+$temp3)/3

NOTE: Use numbers, arithmetic operators, logic operators and named items from the application. Named items are digital inputs, digital outputs, analog inputs and other calculations as shown in Figure 3.12. These items are referenced using their name (for example, $temp1) and are preceded with a dollar sign. For example, if analog input Ø is named ana_inØØ in the Analog Input confi guration, it can be referenced in an equation as $ana_inØØ.

6.Type the units for the calculation in the Display units field.

NOTE: The fi eld, Display units, requires a string value that is displayed with the result of the equation. It is not interpreted or used to affect the value. For example, in Figure 3.12, the Current Value fi eld contains the display unit Deg C, also shown in the Display unit fi eld.

If appropriate values are not entered, a message box displays a list of available operands. The EVR1500 environmental monitor appliance uses standard C programming language operators and functions. Refer to the following table for the allowed operators and functions.

Language Operators and Functions

Operators

Description

Arithmetic

+, -, *, /

 

 

Compare

==, !=, ,=, <, >=. >

 

 

Logical

&& ,

 

 

Functions

abs, acos, asin, atan, ceil, cos, exp, floor, log, round,

 

sin, sqrt, tan, atan2, max, min, pow, random, counter

 

 

7.After typing the calculation equation and units, click the Test Selected button to perform the calculation. This button must be clicked to refresh the value.

8.A message box displays the new calculation. Click OK to exit the message box.

NOTE: Clicking the Test Selected button does not save the confi guration change.

9.Click the Save button to save all of the items in the Configuration tab.