====== Input with Range Monitoring (v1.3) ======

{{:cs:mervis-ide:35-help:safeinput_v1.1.png}}

==== Full Name ====

Lib.Mervis.v1_3.SafeInput

===== Description =====

The auxiliary block is used for monitoring the range of the input variable, filtering it, and potentially switching to a backup value.

==== Required Project References ====

  * Lib.Mervis

===== Usage in ST =====

<code>
program test
    var
        inp: lib.mervis.v1_3.SafeInput;
    end_var

    inp();
end_program
</code>

===== Input and Output Description =====

|Inputs            |Name                                                   |Data Type|Retain|Mandatory Connection                                                                                           |Meaning|
|AlarmPriority     |[[../../Alarms/AlarmPriorityType.htm|AlarmPriorityType]]|No       |No    |Class of generated alarm                                                                                       |      |
|Input             |real                                                    |No       |Yes   |Input value                                                                                                    |      |
|Minimum           |real                                                    |No       |No    |Minimum allowed value                                                                                          |      |
|Maximum           |real                                                    |No       |No    |Maximum allowed value                                                                                          |      |
|Hysteresis        |real                                                    |No       |No    |Hysteresis around //Minimum// and //Maximum//                                                                  |      |
|SafeInput         |real                                                    |No       |No    |Backup value in case of failure                                                                                |      |
|FilterTimeConstant|time                                                    |No       |No    |Time constant of the filter for value filtering. If it has a zero value (t#0s), no filtering is performed       |      |
|Override          |bool                                                    |No       |No    |Input for forced switching to backup value                                                                     |      |


|Outputs|Name                             |Data Type               |Meaning|
|Alarm  |[[AlarmTrigger.htm|AlarmTrigger]]|Trigger variable for alarm|      |
|Output |real                             |Output                   |      |


===== Detailed Function Description =====

The block is used to handle the value, for example from sensors, where in the case of its failure it is replaced by a safe value to prevent inappropriate action by the following blocks. If the //Override// input is true, it forces a switch to the safe value and simultaneously triggers an alarm state. A failure is considered when:

  * The input value is outside the //Minimum// - //Maximum// range
  * The value is NaN (not a number)
  * The value is +inf, -inf


===== Versions =====

{{indexmenu>.085-safeinput#2}}