Plot Overview of the Anal­y­sis Soft­ware IFTA TrendView­er

The most im­por­tant plots and groups of plots for vi­su­al­iza­tion

Rep­re­sents the change of a value over time.

To an­a­lyze the exact value of a sig­nal at a time.

Ex­am­ine the change of a sig­nal in cor­re­la­tion to an­oth­er sig­nal.

The time axes of the plots are au­to­mat­i­cal­ly grouped to­geth­er so that all plots rep­re­sent the same time range, re­gard­less of whether they have an ex­plic­it or an im­plic­it time axis. If re­quired, this group­ing can also be changed or dis­solved. In ad­di­tion, the time axis can also be bound to the time cur­sor and then rep­re­sents a con­fig­urable time win­dow around the time cur­sor.

More top­ics : Ther­moa­cous­tics | Mea­sure­ment tech­nol­o­gy | Sig­nal pro­cess­ing

Plots with an Ex­plic­it Time Axis

Look­ing at the change of a sig­nal over time is one of the most fun­da­men­tal analy­ses.

IFTA TrendView­er of­fers two plots for this pur­pose:

  1. Trend Plot: Dis­plays scalar and Boolean/log­i­cal sig­nals over time. Even sig­nals with dif­fer­ent time res­o­lu­tion can be dis­played in one plot.
  2. In­ten­si­ty Plot: Dis­plays spec­tra as spec­tro­gram. In ad­di­tion, sig­nals with the same unit over time can also be dis­played.

Trend Plot

Use the trend plot to an­a­lyze value changes over time. The time is plot­ted on the x-axis and the val­ues are plot­ted on the y-axis.

Visu­al­ize how a sig­nal changes over time in trend plots. Find de­pen­den­cies in your data by adding mul­ti­ple sig­nals to the plot.

Boolean Trend Plot

Use the Trend plot to ana­­ly­ze value chan­ges over time. The time is plot­t­ed on the x-axis and the va­lues are plot­t­ed on the y-axis.

An­a­­ly­ze boo­lean/logic sig­­nals over time and iden­­ti­­fy points in time at which chan­ges take place. Sig­­nals are au­to­­mat­ic­al­ly stacked and grouped to one y-axis for bet­ter read­­ab­il­i­ty.

In the ex­­am­­ple run-up and run-down si­g­­nals of a ro­­ta­t­ing ma­chi­ne are dis­­­­­played. On the x-axis time is shown and on the y-axis the state (0 for false and 1 for true). As you can see first the ma­chi­ne is in run up state and after a short amount of time it is run down.

 

Wave­form Trend Plot

Use the Trend plot to ana­­lyze value changes over time. The time is plot­t­ed on the x-axis and the val­ues are plot­t­ed on the y-axis.

Ana­­lyze wave­­forms to see how the am­p­l­i­tudes and wave­­forms change over time.

The ex­am­ple shows a dis­­­tance sen­sor sig­­nal from a ro­­tat­ing ma­­chine. On the x-axis the time is drawn, on the y-axis the mag­ni­tude of the sig­­nal is plot­t­ed.

Spec­tro­gram Plot

An­a­lyze fre­quen­cy phe­nom­e­na over time with a spec­tro­gram. Dis­play am­pli­tude changes for all fre­quen­cy lines at once.

In the ex­am­ple the ab­so­lute spec­trum of a pres­sure sen­sor in­stalled in an acous­ti­cal­ly ex­cit­ed burn­er is dis­played. You can see how the am­pli­tude of the first har­mon­ic at a fre­quen­cy of ≈175Hz and in­creas­es and de­creas­es over time.

On the x-axis the time is dis­played, on the y-axes the spec­trum unit, e.g. fre­quen­cy [Hz]. The color bar on the left de­fines the col­ors de­pict­ing the mag­ni­tude of the spec­trum val­ues.

In­ten­si­­ty Plot

Dis­­play a group of sig­­nals with the same unit in one in­­ten­s­i­ty plot. You get an over­view of the val­ues over time. Thus, you can quick­ly iden­ti­­fy sen­sor val­ues which de­vi­ate from the rest of the group and ana­­lyze how val­ues change over time. The plot gives a quick con­­densed over­view over a group of sig­­nals which is su­per­i­or in com­­par­is­on to a trend plot.

In the ex­am­ple, 24 tur­bine out­­let tem­per­at­ures are drawn on the y-axis over the x-axis (time). The tem­per­at­ure is drawn by color, where the color cor­res­ponds to a value dis­­­played on the "color bar" on the left side of the plot. 

Plots Visu­al­iz­ing the Values of a Sig­nal at the Po­si­tion of the Time Cur­sor

Look­ing at the change of a sig­nal over time is one of the most fun­da­men­tal analy­ses. IFTA TrendView­er pro­vides two time cur­sors to an­a­lyze the exact value of a sig­nal at a time.

The fol­low­ing plots show the value of sig­nals to the time cur­sor:

  • List plot
  • Led plot
  • Spec­trum/Array plot
  • Radar plot

List Plot

Dis­­play the val­ues of sig­­nals at the cur­rent time curs­or po­s­i­­tions. Thus, you can quick­ly com­­pare val­ues of dif­fer­­ent sig­­nals and dif­fer­­ent times.

In the ex­am­ple, the cur­rent val­ues of ma­­chine state var­i­ables are shown for time curs­or 1 and 2. Ad­di­­tion­al data is the time, the value dif­fer­­ence be­tween the two curs­ors and the sig­­nal unit. It is pos­si­ble to con­­fig­ure the num­ber of ta­bles, vis­i­ble col­umns and rows.

LED Plot

The LED Plot dis­­­plays states (bool­ean/lo­g­ic­al sig­­nals) at the cur­rent time curs­or po­s­i­­tion. See im­me­di­ate­ly if an error or alarm oc­curs and if your sys­tem is run­n­ing cor­rect­ly.

The ex­am­ple shows sev­er­al bin­ary sig­­nals (green/red for true and grey for false).  A color can be cho­sen for the ac­t­ive and in­­ac­t­ive state.



Wid­get Plot

Use the Wid­get plot to present speed, tem­per­a­­tures or pres­­sure data in an ap­­peal­ing and clear way.

You can cre­ate this plot by drag­ging and drop­ping sig­­nals into an empty plot area. We offer four dif­fer­­ent wid­gets: speed gauge, ther­­mo­me­ter, tank and meter. Mul­ti­­ple sig­­nals can be dis­­­played at the same time, e.g. mul­ti­­ple tem­per­a­­ture sig­­nals. Ad­di­­tion­al­­ly, you can con­­fig­ure thresh­olds for warn­ing and alarms, which are then also vi­­su­al­ized.

Spec­trum Plot

Use the spec­trum plot to ana­­lyze spec­­tra for a se­lec­t­ed point in time. Read the am­p­l­i­tude for all fre­quen­cy lines at once and iden­ti­­fy rel­ev­ant fre­quen­­cies at cur­rent time curs­or po­s­i­­tion.

The fig­ure shows the ab­­so­­lute spec­trum of a pres­­sure sen­sor in­­stalled in an acous­tic­al­ly ex­cit­ed burn­er. The res­on­ance peak at 168 Hz is au­to­­mat­ic­al­ly marked with a label de­pic­t­ing the mag­ni­tude and fre­quen­cy.

The plot is often used in con­junc­­tion with an in­­ten­s­i­ty plot to dis­­­play the val­ues at the cur­rent curs­or point. On the x-axis, the fre­quen­cy is dis­­­played and on the y-axis the mag­ni­tude of the spec­trum.



Array Plot

Dis­­­play a group of si­g­­nals with the same unit in one plot. You get an over­­view of the va­lues at the cur­rent time cur­­sor po­si­ti­on. Thus, you can quick­­­­ly iden­­ti­­fy sen­­sor va­lues which de­vi­a­te from the rest of the group.

In the ex­­am­­ple fi­gu­re you can see 24 tur­bi­ne out­­­­let tem­pe­ra­­tu­res. On the x-axis, the sen­­sor num­ber is dis­­­­­played and on the y-axis the tem­pe­ra­­ture.

Radar Plot

Use the Radar plot to gain a quick over­view over mul­ti­ple sig­­nals at once. You can eas­i­ly see if one sen­sor pro­vides dif­fer­­ent data than other sen­sors for a lar­ger num­ber of meas­ure­­ment sig­­nals.

In the ex­am­ple you can see 24 tur­bine out­­let tem­per­at­ures drawn equidis­tant­ly around the plot ori­­gin.

 

Plots with an im­plic­it time axis

If the change of a sig­nal is not ob­served over time, but over an­oth­er sig­nal, then plots are used which have an im­plic­it (not vis­i­ble in the plot) time axis. This de­ter­mines the time pe­ri­od of the val­ues to be dis­played.

The fol­low­ing plots have an im­plic­it time axis:

  • Bode plot
  • Polar plot
  • Orbit plot
  • Shaft Cen­ter­line plot
  • Camp­bell / In­ten­si­ty map plot
  • XY plot

Bode Plot

Use the Bode plot to ana­­ly­ze ma­chi­ne runs. Dis­­­play fre­quen­­cy re­spon­s­es or har­­­mo­n­ic modes ver­­­sus the ro­­ta­­­tio­n­al speed. You will be able to iden­­ti­­fy cri­ti­c­al speeds and re­­so­n­ances. Eva­lu­a­te an­gles and ma­g­ni­­tu­des of un­­ba­lan­ces by ana­­ly­z­ing speed, am­­pli­­tu­des and pha­s­es, cal­cu­la­t­ed in re­fe­rence to a key­pha­­sor si­g­­nal. By using ma­chi­ne state co­lo­ring you get a quick over­­view over a com­­ple­te run.

In the ex­­am­­ple fi­gu­re you can see am­­pli­­tu­de and phase of the first har­­­mo­n­ic mode of a di­s­tan­ce sen­­sor dis­­­­­played over the ro­­ta­­­tio­n­al speed in [Hz]. The line color de­pends on the ma­chi­ne state (Here: black: slow roll, blue: run up, green: stea­dy state, red: run down).

In ad­di­ti­on to rotor dy­n­a­m­ics ana­­ly­s­is you can dis­­­­­play any com­bi­n­a­ti­on of three si­g­­nals in the Bode plot. Use it to group and dis­­­­­play two time si­g­­nals over a com­­­mon third si­g­­nal.

Polar Plot

Iden­ti­fy res­o­nances or crit­i­cal speeds and dis­play har­mon­ic modes with the Polar plot. Eval­u­ate an­gles and mag­ni­tudes of un­bal­ances by an­a­lyz­ing speed, am­pli­tudes and phas­es, cal­cu­lat­ed in ref­er­ence to a keypha­sor sig­nal. By using ma­chine state col­or­ing you get a quick over­view over a com­plete run.

The ex­am­ple shows the first har­mon­ic mode of a dis­tance sen­sor, which mea­sures the dis­tance to a ro­tat­ing shaft. The imag­i­nary val­ues are plot­ted against the real val­ues while the re­sult­ing points are la­beled de­pend­ing on cor­re­spond­ing en­gine speed val­ues.

The point color de­pends on the ma­chine state (here: black: slow roll, blue: run up, green: steady state, red: run down). The com­plex phase (Φ) and am­pli­tude (r) at the cur­rent cur­sor value are writ­ten in the lower right cor­ner. The cur­rent cur­sor time is dis­played in the lower left cor­ner.

Orbit Plot

In­ves­ti­gate shaft vi­bra­tions and un­bal­ances with orbit plots. Visu­al­ize the mo­men­tary shaft dis­place­ment with re­spect to a sta­tion­ary bear­ing and eval­u­ate the ex­cur­sion of the shaft.
The ex­am­ple shows the orbit of a ro­tork­it shaft de­rived from two or­thog­o­nal dis­place­ment sen­sors. 
The val­ues of mag­ni­tude and angle at the cur­rent cur­sor po­si­tion are shown in the lower right cor­ner. The plot draws two sen­sor po­si­tions cor­re­spond­ing to the x and y sig­nal. Ad­di­tion­al­ly, the ro­ta­tion di­rec­tion is shown in the plot by an arrow.

Shaft Cen­ter­line Plot

Mon­i­tor sta­tion­ary move­ment of shafts with re­spect to sta­tion­ary bear­ings with shaft cen­ter­line plots. Rotor dy­nam­ic ex­perts use this plot to an­a­lyze the dis­place­ment of tur­bine or com­pres­sor shafts mount­ed in hy­draulic bear­ings, as the shafts start to float up­wards due to the ro­ta­tion­al move­ment.

In the ex­am­ple you can see the move­ment of a com­pres­sor shaft from the lower right cor­ner to the upper left cor­ner.

DC val­ues from dis­place­ment sig­nals are dis­played on the x- and y-axis re­spec­tive­ly. A speed sig­nal can be used for la­bel­ing the data points.

Camp­bell Plot

Draw a spec­trum data source in re­la­tion to a speed sig­nal with the Camp­bell plot. Quick­ly iden­ti­fy speed de­pen­dent phe­nom­e­na and an­a­lyze har­mon­ic mode changes.

The ex­am­ple shows the am­pli­tude spec­trum of a shaft dis­place­ment sen­sor over the speed sig­nal of a rotor kit. The first four har­mon­ic modes and how they change in mag­ni­tude can be seen in the plot (red/yel­low lines).

On the x-axis, the speed is dis­played, the y-axis shows fre­quen­cy in Hz. The mag­ni­tude of the spec­trum can be de­pict­ed on the ‘col­or bar’ at the left side of the plot. Ad­di­tion­al­ly, the cur­rent time and range are dis­played in the lower left cor­ner.

In­ten­si­­ty Map Plot

An­a­lyze how am­pli­tudes and fre­quen­cies change de­pend­ing on val­ues of nu­mer­ic sig­nals with the in­ten­si­ty-map.

In the ex­am­ple, the ab­so­lute val­ues of a sound spec­trum in de­pen­dence of the mean tur­bine out­let tem­per­a­ture is shown. On the x-axis, the nu­mer­ic sig­nal, the tem­per­a­ture, is dis­played, the y-axis shows the fre­quen­cy in Hz. The color bar on the left de­fines the col­ors de­pict­ing the mag­ni­tude of the spec­trum val­ues.

The in­ten­si­ty-map plots a spec­trum data source over a se­lectable sig­nal. Ad­di­tion­al­ly, the time is dis­played in the lower left cor­ner of the plot.

XY Plot

Visu­al­ize sig­nal de­pen­den­cies with the XY-plot, by cor­re­lat­ing sig­nals di­rect­ly.

In the ex­am­ple, the mean tur­bine out­let tem­per­a­ture is plot­ted on the y-axis against the elec­tric power. The cur­rent time po­si­tion is shown in the lower left cor­ner of the plot.

The XY plot is used to plot mul­ti­ple data sources with a shared time re­gion, where­by one data source is plot­ted on the x-axis and all ad­di­tion­al data sources are plot­ted on the y-axis.