Chemglass AF-0304 - Manual (Page 19)

17
4.6. Cable Extensions
The indicator and controller models are unique in their
ability to change cable lengths without requiring
recalibration. Typically, for a 2000 mTorr instrument, a
500 foot cable of #18 wire may be added with less than
1 mTorr error.
If factory cables are purchased with the instrument, it will
be calibrated with that cable. Customers making their own
cables may do so to any length, provided the wire resist-
ance is kept at 3.2 ohms or less per lead, e.g. 500 feet of
#18 wire is 3.19 ohms. We suggest using 8-wire #22 for
up to 200 foot lengths. Beyond this, we recommend going
to larger size wire. Wire all pins since all are used for the
various tube types (except pin 2). Be sure to make good
solder joints. Crimped connections are not recommended.
For long cable extensions, shielded wire may be
desirable and is a good precaution against stray electrical
noise. Connect the shield to pin 1, which is circuit
common. Extension cables may be purchased from the
manufacturer in several standard lengths. If you wish to
make your cable extensions, see the pin out details below
for your specific instrument range.
• 100 mTor: 4 wires, pins 1, 5, 6, 8
• 2000 mTorr: 4 wires, pins 1, 4, 5, 8
• 20 Torr: 6 wires, pins 1, 3, 5, 6, 7, 8
Gauge Tube Wiring Reference Table
(Wire Color of Conductors in Extension Cable Shown in Parenthesis)
Pin # 2000 mT 20T 100 mT
Function Color Function Color Function Color
1 GND (BLACK) GND (BLACK) GND (BLACK)
2 — — —
3 — PWR (RED) —
4 PWR (RED) — —
5 SIG (GREEN) SIG (GREEN) SIG (GREEN)
6 — GAIN RES + (BLUE) PWR (RED)
7 — GAIN RES GND (BROWN) —
8 REF (WHITE) REF (WHITE) REF (WHITE)