Differences

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--- thc:thc [2019/11/28 10:15] – ivan
+++ thc:thc [2023/12/28 14:10] (current) – ivan
@@ Line 56: / Line 56: @@
     - Make a test straight cut and check Arc Voltage during the cut (it is "96V" for the setup below). \\ \\ {{hardware:thc:mycnc-thc-011.png}}
-This second method is recommended for more experienced users who want more granularity and quality control.
+This second method is recommended for the more experienced users.
 **5.** Select the proper ratio, as described in the Initial Setup part.
@@ Line 68: / Line 68: @@
 {{:thc:thc-setup-007-acceleration.png}}
-**8.** Set the **THC Low Speed** value. Whenever the speed of the machine will fall lower than this value, the possibility of the arc voltage fluctuating rises greatly. Thus, to prevent the torch from diving, the last height value before the speed goes below your THC Low Speed value is taken and maintained until the speed rises back up again.
+**8.** Set the **THC Low Speed, [%] of feedrate** value. Whenever the speed of the machine will fall lower than this percentage of the feedrate, the possibility of the arc voltage fluctuating rises greatly. Thus, to prevent the torch from diving, the last height value before the speed goes below your THC Low Speed percentage value is taken and maintained until the speed rises back up again.
+The below diagram illustrates the way THC Low Speed works. On corners (green), the speed falls below the typical Feedrate #1 (red), so it can be used to disable THC on sharp corners. Feedrate #2 (blue), which is typically different from Feedrate #1, is used for hole and arc cutting. This way, THC will still be ON at smooth corners:
+{{:thc:plasma-setup-016-percentage-cutting-hole-speed.png}}
+Typically, a good starting point for setting up THC Low Speed value is around 80-95%. That is, when the speed decreases by anywhere from by 5-20%, the system will turn off Torch Height Control.
+//NOTE: It is not recommended to set this value to 100%, as the THC can then be turned off even on straight sections of the work path far away from corners (due to integer operations within the controller).//
 **9.** Select the Hi/Lo event output port (63 by default).
@@ Line 112: / Line 120: @@
 **19.** Select the **THC Jog speed ratio**. This is usually set to be an order of magnitude lower than the working speed, as to not move the torch erratically.
+**20.** Enable **DC Motor Control** for DC motors only, with options for PWM channel and direction.
+**21.** Enable **AxisPlus 0/1 for Height Control** if necessary. The first option can be enabled to utilize the THC settings for AxisPlus (instead of Z-axis only). Second option is reserved for Focus axis (currently in beta testing, usually left disabled).
+**22.** Set the **THC PID dead zone**. This option will monitor the current arc voltage value. If that value differs from the reference by less than the selected value (in ADC units), then no control signal is generated. This is done to potentially reduce the response to noise in the voltage signal readings.
+    * NOTE: For high levels of noise in the arc voltage value readings, the dead zone setting is typically not sufficient to prevent excessive motion on its own. In such a case, it is recommended to either improve noise filtering for the electronics hardware, or to change the PID coefficients within the myCNC software.
 === Check that the THC is ON ===
@@ Line 117: / Line 132: @@
 The next step is to check if THC is ON in the User Settings.
-It can be a button in User settings of an item in PLC settings. Both settings will turn THC on/off and both represent the same variables - the user can decide which one they want to use out of convenience.
+It can be a button in User settings, or a toggle in the PLC settings (Settings > PLC). Both settings will turn THC on/off and both represent the same variables - the user can decide which one they want to use out of convenience. Typically, the User Settings window is used.
 {{:thc:thc-setup-user-settings-001.png}}
@@ Line 145: / Line 160: @@
   * **_Table** - similar to regular Table, with a predefined value for the reference voltage, however the THC Start Delay WILL be used.
   * **_Measure** - similar to regular Measure, the reference voltage value is recorded by the controller prior to the THC Start. THC Start Delay WILL be used.
+  * **Measure 1V** - the reference voltage is measured (similar to the **Measure** setting), but if the voltage has changed a lot relative to the previous reference voltage, then the new value will change no more than the specified value (for example 1V)
+    * For example, if the previous voltage was 125, and 130 was the new measured value, then the new reference voltage will be set to 126
+    * The maximum reference voltage change is set in the THC settings (Settings > Config > Technology > THC):
+{{:thc:thc-setup-015-new-settings.png}}
+  * **_Measure 1V** - similar to regular Measure 1V, with the THC Start Delay.
 A skilled operator can also control the reference arc voltage, if necessary, to bring the torch up/down, however the system allows for a fully automatic Torch Height Control through these settings.
@@ Line 166: / Line 187: @@
   * **IHC Cutting Height**. After the pierce time has elapsed, the machine moves the torch to the cutting height at which the cutting will begin.
   * **THC Start Delay** signifies the time for which Torch Height Control is not turned on after the cutting has started (to prevent metal splashes/voltage variations that are often present at the beginning of the cut to impact the cutting procedure). This delay can be set to ON or OFF in the User Settings.
-  * **THC Pre-off time**. In order to prevent sudden movements due to rapid voltage changes as a cut (especially when cutting a hole) is done, THC can be turned off some time before the end of the cut and the machine will be kept at a set height until the THC system will move to the next cut.
+  * **THC Pre-off time**. In order to prevent sudden movements due to rapid voltage changes as a cut (especially when cutting a hole) is finishing up, THC can be turned off some time before the end of the cut and the machine will be kept at a set height until the THC system will move to the next cut.
   * **Lift After Cut Height** to move the torch up to after the cut has completed.