erface to drive system

0 V - common

+24V - supply

+UP - output

+DOWN - output
- cable fault detection - open, short
- internal adjustment for setup
- external adjustment for fine tuning










4
3
2
1
U/D
POT
BNC
i
n
p
u
t
/
o
u
t
p
u
t
cable
gland








Description:


SENSING RING:

The metal ring is connected to the R982 via a 500 mm
long 50 ohms coaxial cable (RG316U or equivalent; OD
2.5 mm PTFE 96 pF/meter). The size of the ring should be
around 3000 mm
2
, typically, ID 50 mm and OD 80 mm of
the ring. Nominal height of the ring should be between 5
to 20 mm above the plate. Thickness of ring is not critical
nor the distance from the ring, to the end of the coaxial
cable. The typical thickness of material for ring is 3 mm a
distance from ring to end of the coaxial cable is 20 cm.
The ring must be insulated from all conductive parts of the
cutting torch and must be connected to the middle core of
the
coaxial cable. End of the cable must be terminated with a
1 mega-ohms resistor. See picture on the next page.


INTERFACE:

The connection of supply/outputs to the R982 sensors is
via 4 core cable. A screened cable should be used and
gland can accept cable of diameter between 3 and 6.5 mm
OD. The supply is a nominal DC 24 volts (18 - 35 volts).
The power consumption is less than 50 mili-amps. The up 2
and down outputs are P-channel mosfets (Ron = 0.3 ohms,
Id < 4 amps). These outputs can directly drive coils of 24
volts relays or digital inputs of NC/drive control or they
might be used as high side half of the bridge driver.




GROUNDING: The R982 sensor is floating. There is no
requirement, that external power supply must or must not
be grounded. The internal circuitry is connected to the
diecast box of R982 via a 1nF/630V capacitor. The diecast
box must be connected to the cutting plate. Usually the
sensor is bolted to the housing of torch lifter and cutting
table must be connected to the frame of the machine, what
makes a sufficient connection.

ADJUSTMENT: Set adjustment pot to middle position.
Manually adjust the torch lifter, so the ring is about 20 mm
above the plate. Disable the drive system (e.g. electrically
or mechanically disconnect motor). Activate THC and
monitor up and down output. Gently adjust the core of
internal coil of R982 sensor so no up nor down output is
activated. Decrease the distance between sensing ring and
plate and verify that up output is activated. If down output
is activated instead of up readjust the core of the coil and
find second 0. Disconnect BNC connector and verify
that up output is activated. Reconnect the drive system.

The correctly adjusted sensor should activate outputs if
error is about plus or minus 10 % of nominal height. This
makes about +/- 0.5 mm at 5 mm above the plate up to +/-
2 mm at 20 mm.

APPLICATION: Below is simplified typical connection
of R982 sensor. The limit-switches can be connected in
series with motor as normally closed bridged with a power
diode, which allows to drive motor only opposite way of
position of the limit switch. A power resistor of few ohms
should be connected in series with motor to avoid the
burning of contacts of relays and brushes of motor. Small
electrolytic capacitors can be connected in parallel with
each relay. This will increase the hold time of the relay.




S1
UP/DOWN SW
K2
DC24V
K1
DC24V
A
-
+
M1
UP/DOWN MOTOR
SUPPLY FOR MOTOR +V
SUPPLY FOR MOTOR 0V
S2
THC ON
+24V
0 V
+ UP
+DOWN
982-000
THC SENSOR
+24V
0 V
+ UP
+DOWN
SUPPLY FOR THC +V
SUPPLY FOR THC 0V





Document R982.DOC rev 1.00 date 10-06-98
(c) 1998 Rutex
All rights reserved.

Rutex
8 Jean Ave, Berkeley Vale 2261, Australia
PO Box 3500, Wamberal 2260, Australia
www.rutex.com

mail@rutex.com

tel.: +61-418283157
fax: +61-292259931