Differences

This shows you the differences between two versions of the page.

--- thc:thc [2019/11/28 10:11] – ivan
+++ thc:thc [2020/03/13 10:17] – ivan
@@ Line 33: / Line 33: @@
 In order to set up THC completely, follow the instructions below:
-. Select the green check mark in the **THC Enabled** field.
+**1.** Select the green check mark in the **THC Enabled** field.
 {{:thc:thc-setup-003-thc-enabled.png}}
-. Select the number of THC you have in your setup (usually 1)
+**2.** Select the number of THC you have in your setup (usually 1)
 {{:thc:thc-setup-004-number.png}}
-. Select the feedback channel as described in the procedure above.
+**3.** Select the feedback channel as described in the procedure above.
-. Select your reference voltage. This can be done in two ways:
+**4.** Select your reference voltage. This can be done in two ways:
 - By using a value from literature (by going to the Tool Configuration window, or your manufacturer's manual tables)
@@ 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.
-. Select the proper ratio, as described in the Initial Setup part.
+**5.** Select the proper ratio, as described in the Initial Setup part.
 {{:thc:thc-setup-005-ratio.png}}
-. Set the THC Maximum Speed (usually set to be lower than the usual machine speed to make the movement slightly less erratic)
+**6.** Set the THC Maximum Speed (usually set to be lower than the usual machine speed to make the movement slightly less erratic)
 {{:thc:thc-setup-006-max-speed.png}}
-. Set the Acceleration Ratio. It is set to be 20 by default, thus setting it to 50 as in the example below will make the acceleration ratio 2.5 larger than the default, from 100% to 250%.
+**7.** Set the Acceleration Ratio. It is set to be 20 by default, thus setting it to 50 as in the example below will make the acceleration ratio 2.5 larger than the default, from 100% to 250%.
 {{:thc:thc-setup-007-acceleration.png}}
-. 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.
-. Select the Hi/Lo event output port (63 by default).
+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:
-. Select the **THC Small Radius** value. THC will be turned OFF when the value of the cut radius is lower than that specified in this field.
+{{:thc:plasma-setup-016-percentage-cutting-hole-speed.png}}
-. Select **Alarm Arc Voltage difference**. This setting helps prevent the torch from diving while moving through the cut, on low speed corners, etc. The Voltage Difference takes the absolute difference value between the real and the reference voltage. In case of a voltage spike, for example due to the metal part being cut off and the material falling to the ground, this stops the THC from trying to adjust for that by diving after a falling part. This value allows for granular control depending on the operator's needs, and should be set depending on the operator setup.
+**9.** Select the Hi/Lo event output port (63 by default).
-. Select **Alarm Arc Voltage Rise**. This setting looks at the rate at which the voltage is changing - thus, if there has been a single rapid spike to a new voltage value, for example, such as after metal warping due to the heat, the machine will temporarily disable THC until the rise (the derivative of the voltage difference) is stable again. This is useful for when Torch Height Control needs to be turned off temporarily, but still function after a voltage spike.
+**10.** Select the **THC Small Radius** value. THC will be turned OFF when the value of the cut radius is lower than that specified in this field.
+**11.** Select **Alarm Arc Voltage difference**. This setting helps prevent the torch from diving while moving through the cut, on low speed corners, etc. The Voltage Difference takes the absolute difference value between the real and the reference voltage. In case of a voltage spike, for example due to the metal part being cut off and the material falling to the ground, this stops the THC from trying to adjust for that by diving after a falling part. This value allows for granular control depending on the operator's needs, and should be set depending on the operator setup.
+**12.** Select **Alarm Arc Voltage Rise**. This setting looks at the rate at which the voltage is changing - thus, if there has been a single rapid spike to a new voltage value, for example, such as after metal warping due to the heat, the machine will temporarily disable THC until the rise (the derivative of the voltage difference) is stable again. This is useful for when Torch Height Control needs to be turned off temporarily, but still function after a voltage spike.
 {{:thc:thc-setup-008-arc-alarm.png}}
@@ Line 83: / Line 87: @@
 the THC.
-. Set the **THC Start Delay**. This sets a value, in seconds, after which THC will begin during the cutting process. During the beginning of the cut, there may be splatter/arc voltage fluctuations which would interfere with THC, so it is often necessary to wait a fraction of a second before turning the THC ON.
+**13.** Set the **THC Start Delay**. This sets a value, in seconds, after which THC will begin during the cutting process. During the beginning of the cut, there may be splatter/arc voltage fluctuations which would interfere with THC, so it is often necessary to wait a fraction of a second before turning the THC ON.
-. Set **THC Restart Delay** to select the value (in seconds) for which to delay the THC after starting it up again to avoid sudden dives.
+**14.** Set **THC Restart Delay** to select the value (in seconds) for which to delay the THC after starting it up again to avoid sudden dives.
-. Set the **THC P- and I- control ratios**. These will vary depending on sheet thickness and the type of plasma power source you are using. The higher the P-ratios absolute values, the higher the Height Control Speed.
+**15.** Set the **THC P- and I- control ratios**. These will vary depending on sheet thickness and the type of plasma power source you are using. The higher the P-ratios absolute values, the higher the Height Control Speed.
 According to our experience, I-ratios should be set around "-2...-6", since higher I-ratio values may lead to oscillation during height control.
@@ Line 95: / Line 99: @@
 {{:thc:thc-setup-009-pi-ratios.png}}
-. Set the **THC pre-off** value (in seconds). This allows to turn THC control OFF before the cutting completes (for example, if we know that THC is not required at the very end of the cutting operation). This value can be set to 0 if not required by the user (majority of user cases).
+**16.** Set the **THC pre-off** value (in seconds). This allows to turn THC control OFF before the cutting completes (for example, if we know that THC is not required at the very end of the cutting operation). This value can be set to 0 if not required by the user (majority of user cases).
-. Set the **Cutting pre-off** value (in seconds). This allows to stop the cutting some fraction of a second before the machine stops moving at its working speed and may be useful to some users/operators depending on their cutting needs and machine configuration. This value can be set to 0 if not required by the user.
+**17.** Set the **Cutting pre-off** value (in seconds). This allows to stop the cutting some fraction of a second before the machine stops moving at its working speed and may be useful to some users/operators depending on their cutting needs and machine configuration. This value can be set to 0 if not required by the user.
-. Select whether you want to **accept jog while THC is activated**. This allows for jog in the z-axis while THC is on in order to allow the user to lift/lower the torch manually through operator inputs in addition to the regular THC control. This field can be set to OFF if the user does not want to be able to accidentally move the torch during the cutting process while the THC is ON.
+**18.** Select whether you want to **accept jog while THC is activated**. This allows for jog in the z-axis while THC is on in order to allow the user to lift/lower the torch manually through operator inputs in addition to the regular THC control. This field can be set to OFF if the user does not want to be able to accidentally move the torch during the cutting process while the THC is ON.
 {{:thc:thc-setup-010-accept-jog.png}}
@@ Line 111: / Line 115: @@
 {{ :thc:thc-jog-003-position.png}}
-. 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.
+**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.
 === Check that the THC is ON ===
@@ Line 117: / Line 121: @@
 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 166: / Line 170: @@
   * **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.