Issue
Supplemental Documentation on the Menta SEQ (sequence) block
Environment
Menta
Cause
The document is intended to clarify the inputs and configuration parameters of the Menta SEQ block and when/how to use them.
Resolution
Click here to download a copy of this document in PDF format
Click here to download the example Menta macro
Supplemental Documentation: Menta SEQ
A Brief Overview of Sequence Block
The Sequence block is used to start N of M stages based on a percentage input. Each stage is represented by a single bit in the output of the block which requires calculation to determine if each stage is off or on.
The Sequence block also provides the ability to rotate the stages, specify a delay between multiple stages activating, and a hysteresis to adjust the activation or deactivation of stages.
The Sequence block is ideal for rotating operating stages that have high frequency of change. It is not the proper block to use for run time balancing between multiple stages.
Input of the SEQ Block
The input expects a 0-100 value where a 0 represents zero stages active and 100 represents all stages are active.
Configuration Parameters of the SEQ Block
Stages
The number of stages to activate at 100% input.
Rotate
Rotation Flag. If Rotate is set to 0 then the first stage will always be active if 1 stage is required. If Rotate is set to 1 then the first stage to activate will be the first stage to deactivate.
Period
Time delay(ms) between multiple stages activating.
Hysteresis
Hysteresis is used to offset the activation or deactivation % for each stage. If the Hysteresis is positive then it will shift the activation % higher by that amount. If the Hysteresis is negative then it will shift the deactivation % lower by that amount.
Normal Operation of 4 Stages:
|
|
Stage 1 Activation |
Stage 2 Activation |
Stage 3 Activation |
Stage 4 Activation |
|
Input |
20% |
40% |
60% |
80% |
Hysteresis of 10%
|
|
Stage 1 Activation |
Stage 2 Activation |
Stage 3 Activation |
Stage 4 Activation |
|
Input |
30% |
50% |
70% |
90% |
Hysteresis of -15%
|
|
Stage 1 Deactivation |
Stage 2 Deactivation |
Stage 3 Deactivation |
Stage 4 Deactivation |
|
Input |
5% |
25% |
45% |
65% |
Output of the SEQ Block
The number of stages active is based on the following formula:
Active Stages = ((Maximum Stages +1) * Input) / 100
The number of active stages is then encoded into an Integer as the output of the SEQ block where each bit represents whether each stage is active or inactive.
Since this is a single value it must be decoded using expression blocks to detect if each bit is active.
