Fluke 2180A - Manual (Page 72)

Power On Reset (POR) via Q4 and U16. The POR resets
U5 and Ull, and lasts for approximately 150 ms.
604-34. The power supply for Option 21XOA-004 power
supply is a standard linear regulator using a full-wave
center tap rectifier and pass transistor regulator (Q5). The
regulator is driven by U17 and Q6, and is referenced from a
2.5-volt band gap reference (U15). U16 performs POR and
low voltage detection. The option provides its own power
rather than using the power supply of the thermometer,
which is unable to provide enough additional power.
604-35. Option 21X0A-004 is a consolidation of the cir­
cuitry from Option 21X0A-002, Option 2XXXA-522, and
1120A that is required for IEEE-488 output operation. The
consolidated circuitry does not include analog output cap­
ability or the slow serial communication link between the
Option 21X0A-002 and 2XXXA-522 microprocessors.
Instead, the circuitry uses the PTI (Portable Test Instru­
ment) parallel output port of the Option 21X0A-002 to
communicate with the Option 2XXX A-522 microprocessor.
604-36. COMPATIBILITY WITH 2300A
AND PREVIOUSLY PRODUCED
THERMOMETERS
604-37. Option 21X0A-004 is not intended to be used
with a thermometer that is a part of a 2300A Scanning Sys­
tem. In a 2300A system, an Option 2300A-005 or Option
2300A-006 should be installed in the 2300A for connection
to the IEEE-488 bus. Option 2300A-005 is for output only,
similar to Option 21X0A-004 operation. Option 2300A-006
additionally provides remote control of the 2300A. Options
2300A-005 and 2300A-006 use the 2XXX A-522 and 1120A
for connection to the IEEE bus.
CAUTION
21XOA-004
“2190”, the thermometer is an early version. Newer versions
begin with “800” or “900.”
604-39. If your thermometer is an early version, either of
the following two modifications may be performed:
1. The microprocessor in the thermometer can be
replaced with a newer version. Contact your local
John Fluke Service Center to order the latest
2180A or 2190A standard versions.
a. When you are updating a 2180A to the latest
version, be aware there are changes in the avail­
able choice of Resistance Temperature Detec­
tor (RTD) linearizations. If you require the
original linearizations, order a special retrofit
kit Model 2180A/AYK. (P/N 796953)
b. When you are selecting from the latest versions
of 2190A linearizations, be aware that an
enhanced microprocessor retrofit kit is also
available. The enhanced retrofit kit provides 15
thermocouple types. Order Model 2190A/ AMK
(P/N 763292)
2. A modification to Option 21X0A-004 may alter­
natively be performed. Contact your local John
Fluke Service Center and arrange for the installa­
tion of a 2180A-4021W (JF P/N 539288) onto
Option 21X0A-004. QI and Q3 are removed from
the pea and replaced by the modification circuit.
This modification makes Option 21X0A-004
compatible with all versions of 2180A and 2190A
thermometers. A +5 volt connection is provided
next to U2 to provide power to the added modifi­
cation circuit.
Option 21X0A-004 is not compatible with a
2300A Scanning System. Such use may cause
channel numbers to be displaced by one read-
ing, and each reading may be output twice.
604-38. Option 21X0A-004 is not directly compatible
with the earliest version of the 2180 A and 2190A thermome­
ters. A choice of either of the two modifications described
below provides compatibility. To identify the early version
of thermometer, observe the thermometer display as it is
turned on. If the display characters begin with “2180” or
604-40. PERFORMANCE TEST
604-41. There are no adjustments or calibration.
604-42. With Option 21X0A-004 attached to a 2180A or
2190A thermometer, apply proper ac input voltage and
measure for 5.05 ± O.I volts dc across TPl and TP2.
604-43. Connect Option 21XOA-004 to an IEEE-488 con­
troller via the IEEE-488 bus. Execute the SRQ program in
Figure 604-1 to retrieve readings from Option 21X0A-004.
604-6