Hypertherm SensorOHC - Manual (Page 17)

Section 3: Installation and Set Up 13
Limit Switch
The lifter upper and lower limit switches are connected to the 9 pin “D” connector. These switches
are normally closed switches that open when the limit is reached. The upper limit switch connects
between pins 5 & 6 and the lower limit switch connects between pins 2 & 3. This connector also
provides limited +12 Vdc on pins 1 & 4 that can be used to power either optical or hall-effect limit
switches.
Limit Switch Pinout
9 Pin D-Sub
Pin Description
2 Lower Limit ( contact closure )
3 Lower Limit ( contact closure )
5
Upper Limit ( contact closure )
6 Upper Limit ( contact closure )
Digital I/O
The digital I/O interface on the 15 pin “D” connector should include a switch to select between
manual and automatic operation. This switch connects from the input on pin 3 to the signal return
on pin 2. When this switch is closed, the unit will operate in manual mode. The digital I/O
interface also needs a three position center off momentary Up/Down switch to operate in manual
mode or manual override in automatic mode. When the input on pin 4 is connected to the signal
return, the slide will be driven up; and when the input on pin 5 is connected to signal return, the
slide will be drive down. The “Second height Select” input on pin 6 is used to select a second
height set-point from an optional external pot. The optional status output signals “In-Position”,
“Error” and “plate Contact” are available on pins 7 , 8 7 9 respectively. The outputs are transistors
connected to signal return and are capable of switching up to 30V at 100 mA each. A source of
+12V dc is available on pin 1, for use in interfacing to the output signals. Care should be taken
that the total +12 Vdc current drawn from pin 1 plus the current drawn from pins 1 & 4 of the 9 pin
“D” connector, does not exceed 50 mA.
Optional External Height Set Pot
An optional 10K pot can be connected between pins 10 & 11 to allow external setting of the
automatic height set-point. This pot will work in conjunction with the unit’s front panel height
setting pot and both will affect the height set-point. The control unit front panel set pot and the
external set pot are electrically in parallel. This will cause some non-linearity in the height set
point. Usually the front panel control is used as the coarse adjustment and the external pot will
provide a fine tuning of the set point.
Optional External Second Height Set Pot
An optional 10K pot can be connected between pins 12, 13, & 14. This pot will provide an active
height set-point whenever the digital “Second Height Select” input is switched active by
connecting the input on pin 6 to the signal return on pin 2. Unlike the external pot for normal
height set point, this pot will completely override the control front panel height set point. This
external point will provide a linear adjustment of height vs. set point