===== THC API - Control THC from PLC procedure =====

Torch Height Control normally controlled from PLC procedure. THC should be switched ON just after Pierce procedure finished and should be switched OFF before switcheing off cutting process. In some cases switching THC ON/OFF can be made from special M-codes like M14, M15, M50, M51. 

THC API offers simple access to THC Control from PLC procedure.

We have two API versions to access to THC.

==== API #1 ====

Several Global Variables registers are mapped to get access to THC features.



^ Variable Name ^ Value ^ Comment ^
^ THC #0 Registers ^^^
| GVAR_THC0_CONTROL | 7570 | THC #0 Control register.\\ Writing 0 to this register will turn THC off.\\ Writing 1 - Immediate (No delay) start THC\\ with pre-defined  Reference Value\\ Writing 2 - Start THC with Delay\\ (THC on delay parameter in THC settings) and pre-defined Reference Value\\ Writing 3 - Update Reference Value (Measure ADC channel)\\ and Immediate Start THC with new Reference\\ Writing 4 - After Delay update Reference Value\\ (Measure ADC channel) and Start THC with new Reference |
| GVAR_THC0_INPUT | 7571 | Writing to this register will change ADC channel\\ used for THC control.\\ ADC numeration starts from 0x10\\ 0x10 - ADC #0\\ 0x11 - ADC #1\\ 0x12 - ADC #2\\ 0x13 - ADC #3\\ 0x14 - ADC #4\\ 0x15 - ADC #5\\ 0x16 - ADC #6\\ 0x17 - ADC #7\\ |
| GVAR_THC0_VREF | 7572 | Writing to this register will change Reference Value for THC #0.\\ Reading register will return THC #0 current Reference Value |
| GVAR_THC0_OFFSETZ | 7573 |Reading this register will return current THC #0 Speed. Register value is used to display current speed of THC #0 system |
| GVAR_THC0_ENABLED | 7574 | THC #0 Enable Register.\\ Writing 0 will Disable THC #0. Writing to THC #0 Control register will be ignored.\\ Writing 1 - will Enable THC #0 |
^ THC #1 Registers ^^^
| GVAR_THC1_CONTROL | 7575 | See THC #0 above |
| GVAR_THC1_INPUT | 7576 | See THC #0 above |
| GVAR_THC1_VREF | 7577 | See THC #0 above |
| GVAR_THC1_OFFSETZ | 7578 | See THC #0 above |
| GVAR_THC1_ENABLED | 7579 | See THC #0 above |
^ THC #2 Registers ^^^
| GVAR_THC2_CONTROL | 7580 | See THC #0 above |
| GVAR_THC2_INPUT | 7581 | See THC #0 above |
| GVAR_THC2_VREF | 7582 | See THC #0 above |
| GVAR_THC2_OFFSETZ | 7583 | See THC #0 above |
| GVAR_THC2_ENABLED | 7584 | See THC #0 above |
^ THC #3 Registers ^^^
| GVAR_THC3_CONTROL | 7585 | See THC #0 above |
| GVAR_THC3_INPUT | 7586 | See THC #0 above |
| GVAR_THC3_VREF | 7587 | See THC #0 above |
| GVAR_THC3_OFFSETZ | 7588 | See THC #0 above |
| GVAR_THC3_ENABLED | 7589 | See THC #0 above |


Examples.
Switch On THC#0 and THC#1 in **M03** Oxyfuel Gas Cutting ON procedure (2x gas cutting heads configuration). Pre-defined Reference Value is used, THC will be started after delay, defined in Cfg->Technology->THC configuration dialog, **THC delay, s** item.
<code>
if (thc_enabled!=0)
 {
   gvarset(7570,1); //THC #0 ON
   gvarset(7575,1); //THC #1 ON
 };
</code>


Switch Off THC#0 and THC#1 in **M05** Oxyfuel Gas Cutting OFF procedure (2x gas cutting heads configuration)
<code>
   gvarset(7570,0); //THC #0 ON
   gvarset(7575,0); //THC #1 ON
</code>