Temperatureis generally sensed at the tip of the probe. To get an accurate tem-
perature measurement theprobe sheath should be well immersed, with ade-
quate depth and fit, into the medium to be measured.
CAUTION: Probes are fragile devices that can be easily damaged by me-
chanical shock, overheating, and absorption of moisture or fluids in the
wires or hub. Damage may not be visibly apparent but nevertheless can
cause drift, instability, and loss of accuracy. Observe the following pre-
cautions:
Do not allowprobes to be dropped, struck, bent, or stressed.
Do not overheatprobes beyond their recommended temperature range.
Do not allowany part of the probe other than the sheath to be immersed in
fluid.
Do not allowthe probe hub or wires to be exposed to excessive temperatures.
Keepthe probe wires clean and away from fluids.
6.6 INFO-CON Connector
The probe connects to thetop of the1522 using a Hart INFO-CON connector
(see Figure3 on page 21). The probe connector fits snugly and locks into place
when it is fullyinserted. The connector includes a memory device that stores
the uniquecharacteristics of the probe, allowing the instrument to measure tem-
perature accurately.Generally, the probe is purchased with the connector at-
tached and programmed by the factory.Connectors can be purchased separately
and installedonto probes by the user. The INFO-CON can be programmed di-
rectly from the1522 or from a PC with the optional Model 2372 accessory and
9972 software.
If it is necessary to install the INFO-CON onto a probe in the field, follow the
diagram belowfor connecting the wires of the probe to the connector terminals.
CAUTION:Before opening the INFO-CON case, be sure to be grounded
with an ESD strap to avoid damaging the memory chip.
Forfour-wire probes, one pair of wires attaches to terminals C1 and P1 and the
other pair attaches to terminals C2 andP2. ( C1 and C2source current and P1
and P2 sense the potential.)If a shield wire is present, it should be connected to
the GND terminal (see Figure 7).
A two-wireor three-wire probe can also be used with the instrument. The
two-wireprobe is connected by one wire to the C1 and P1 shorted terminals
and the other wireto the C2 and P2 shorted terminals. Recognize that accuracy
may be significantlydegraded using a two-wire connection because of wire re-
sistance. A three-wire probe is connected by attaching the common wires to the
29
6 General Operation
INFO-CON Connector