如题所述
概要
在智能向导应用中，测试信号由叠加了中高频脉冲的主要阶跃组成。一个典型的测试信号如下所示。
附原文：
Overview
In a SmartStep application, a test signal consists of a major step superimposed with medium and high frequency pulses. A typical test signal is shown below.
A step cycle for a manipulated variable consists of one large move up (or down) followed by another large move down (or up).
Major step
Each major step (large move) will be held for a period of time as specified by parameter STMVDUR. This means a full step cycle will last 2×STMVDUR minutes. The step size requested by the control engineer may be further limited by the SmartStep engine, such that the move size is maximized subject to all variable constraints (including: STMVMAXSTEP, ULINDM / LLINDM, STCVMAX / STCVMIN, STRAMPRT).
If the previous step direction is up (or down), then the next step will be down (or up). For the initial major step, when the MV step size is constrained by a CV limit, the step direction will be determined by the enforcing the maximum move size.
If a move in either direction will have the same move size (move size constrained by STMVMAXSTEP), then the SmartStep engine will randomly choose the direction for the initial major step.
Although the step size is calculated by the SmartStep engine, the user has the option to implement only a fraction of the step by changing the parameter STSTEPFRAC (range between 0.0 and 1.0).
Medium and high frequency pulse
The medium and high frequency pulses are superimposed onto the major step after satisfying a pre-determined waiting period.
The magnitude of the final test signal (after superimposition) is always within the step size. The frequency of the pulses has a random component, but is tuned by setting STMVPULDUR. STMVPULDUR is the frequency pulse duration as a fraction of the MV step duration (STMVDUR). The magnitude of the pulses also has a random component and is tuned by setting STMVPULFR, which is the frequency pulse amplitude as a fraction of the major step size (STMVMAXSTEP).
Additional parameters for test signal control
A SmartStep tester application also provides additional mechanisms to allow control of the signal profile. You can limit a maximum allowed move size in each direction in a running cycle (STMVMAXU and STMVMAXD).
Additional notes
•Note that high and medium frequency pulsing can be eliminated for the entire test group by using the TEST-NOPULSE mode for STGREQ.
Test signal configuration parameters
The following parameters can be used to define the magnitude, duration and shape the MV step signal.
