14. Performance and best practices
This guide gives no figure for the dashboard's maximum size, for gauges per screen or for upload time: the app does not impose these limits, and they depend on the device. Test on the device that will be used, with the complete dashboard, before delivering it.
#14.1 What the app limits
| Item | App rule |
|---|---|
| Screens per target | 4. The Video Overlay has 1. Set it in Number of screens. |
| Image background | Reduced to the target's size, never enlarged. Saved as JPEG, quality 85, no transparency. |
| Pointer PNG | Above 512 px on the longest side, reduced to 512. Saved as PNG with transparency. |
| Image | A PNG or JPEG above 1920 px on the longest side is reduced. |
| GIF | No file size limit. At most 300 frames: 24 per second on both FT700s (7" and Plus) and 60 on the PC, phone and tablet (section 14.4). |
| Map | Cap of 128 MiB (about 134 million bytes), with the images in base64 and before compression. Above that, the app neither saves nor opens the map. The unit's practical limit is checked on the device. |
There is no limit on gauges per screen or on the size of SVG Pointer and SVG Button, and no limit shows a warning: build in stages and check the opening on the device.
#14.2 What makes the map large
Images are stored in the map in base64, at 4/3 of the file size: a 3 MB image takes up about 4 MB. The day background and the night background are two images per screen, and the map carries all 7 targets.
#14.3 Images
- Make the background at the target's size: 1074 x 600 px on the 7" FT700 (section 2.3) and 1920 x 720 px on the FT700 Plus. A background with transparency loses the channel without warning. With Fill, the image is stretched without preserving the aspect ratio (section 5.2).
- For a large, sharp pointer, use the SVG Pointer: the Pointer PNG is capped at 512 px.
#14.4 GIF
- Both FT700s (7" and Plus) keep 24 frames per second of GIF duration; the PC, phone and tablet, 60. With an average delay below about 41.7 ms per frame, the FT700s drop frames; with 50 ms or more, the FT700s and the PC keep the same frames (section 7.2). The editor shows Loaded (N frames) with the number for the device in use.
- A 2-frame GIF (light off and on) is not reduced if the sum of the two delays is 42 ms or more (section 7.2). It switches without hysteresis; for hysteresis, use the image with Conditional visibility (section 10.4).
- Prepare the GIF at the size at which it appears: the app never enlarges it.
#14.5 Value refresh rate
The gauge is redrawn at the rate of the measurement it reads (section 9.5).
| Rate | Interval | Measurements |
|---|---|---|
| 30 per second | 33 ms | Engine RPM, MAP, TPS |
| 15 per second | 67 ms | See the update column in section 9.2 |
| 10 per second | 100 ms | Temperatures, battery voltage |
A gauge without a Data source, such as the Shift, is updated 10 times per second. In version 3.00.54 there is no field to reduce the rate at which the number changes. For a number that changes too fast, also show the measurement as a bar or pointer.
#14.6 Opening the dashboard on the FT700
When the dashboard opens, the FT700 builds all the gauges of the screens and may show Loading dashboard, with X of N gauges and starting.... This happens on the first opening after the unit is turned on and after changing the map name, the screen the dashboard opens on or the number of gauges on that screen. On other openings, only if the last opening took longer than 300 ms. The criterion is time, not the number of gauges.
#14.7 Writing a large map
Large images increase the map and the upload time. The map is sent compressed, in sections of 60,000 bytes for the FT700 and about 5 KB for the FT470.
#14.8 Phone, tablet and PC
The phone editor and the tablet editor are simpler than the PC one; the tablet one does not have the Conditional visibility section.
#14.9 What to check before trusting the number
The dashboard shows the last value it received from the VCU; if the connection drops, only the RPM goes to 0 (details in section 9.6):
- With no data, the measurement is 0, and the O2 sensor, 1. With the RPM at 0 and the other measurements frozen, check the connection before concluding that the engine has stopped.
- A light with Below the lower limit starts lit with no data. A light with Above the upper limit and Switch off below (hysteresis) at 0 starts lit and does not turn off. A Shift with a shift point at 0 stays lit.
#14.10 Work routine
Before writing, go through the list in section 3.3 and also check: the Number of screens and the Initial screen; images at the target's size; Data source on each reading gauge; Save changes done and the screens exported as .ftds.
After writing, open the dashboard from the unit's menu and check gauges, backgrounds (day and night), buttons, lights and the opening time. The editor has no value simulator: connect the unit and, in a safe environment, start the engine and check the real values.