Environmentalcondition; Basicbenchmeasurements - Keithley 485 Instruction Manual

Table 2-l. Error Messages
Display Message Comments
im RAM Error
Model 485 locks up. See Section 5 for troubleshooting information.
IpEz
Calibration Error Model 485 locks up, but operation can be restored by pressing
INVRAM Failure) any one of the four momentary pushbuttons. If restored, calibration
kiir-
is invalid as indicated by the flashing "CAL" annunciator. See Sec-
tion 5 for troubleshooting information.
Overrange Overrange input applied to the Model 485. Leading minus sign
indicates that input signal has a negative value.
2.6 ENVIRONMENTAL CONDITIONS WARNING
Before operating the Model 485, observe
All measurements should be made at an ambient temperature
within the range of O°C to 50°C, and with a relative humidity
of 0% to 70% up to 35OC. For instruments above 35OC
derate humidity 3% per OC up to 50°C. If the instrument has
been subjected to extremes of temperature, allow sufficient
time for internal temperatures to reach environmental condi-
tions. Typically, it takes one hour to stabilize a unit that is
10°C IlEaF) out of specified temperature range.
the safety precautions found preceding
Section 1. Failure to observe these and
other safety precautions found in this
manual could result in severe injury or
death.
WARNING
Do not exceed 30V RMS between input low
and power line ground or a shock hazard
2.7 BASIC BENCH MEASUREMENTS
will result. Also, current inputs that exceed
3mA may be erroneously displayed as a"
Basic measurement techniques for using the Model 485 to
measure DC current are covered in the following paragraphs.
Also included is the operation of the MinIMax and 100 point
data store. A summary of range, accuracy and maximum
allowable input information is given in Table 2-2.
on-scale reading.
CAUTION
Do not exceed the maximum input limits
shown in Table 2-2.
Table 2-2. Range, Accuracy and Maximum Allowable Inputs
r
Range
2 nA
20 nA
200 nA
22$
200 PA
2mA
Minimum
Recommended Maximun
Maximum Accuracy Source
Allowablt
Flli;lry i *l%Reading + Counts1 Resistance
Input
lB°C -28OC (Note 2) (Note 3)
1.9999 nA 0.4 + 4
1OOMB 350v
19.999 nA 0.4 + 1
1OOMB 350v
199.99 nA
0.2 + 1
10MB 350v
1.9999 pA
0.15 + 1 1MB 350v
19.999 pA 0.1 + 1 100 kC 5ov
199.99 pA 0.1 +1 10 kB 5ov
1.9998mA 0.1 +1
1 kKl 5ov
IOTE:
Current above maximum will result in an "OL" display.
,. Source resistances lower than these may result in higher instrument noise and drift.
i. Maximum Transient Overload Voltage: IOOOV with a series 1OOkB resistor. Safe
operation and good measurement practice dictates use of an external resistor when
necessary to limit input currents to less than 3mA.
Maximum volts-hertz product (common mode): 108V.H~
1
1
2-3