13
Accessories:
Test lead pair; batteries installed;
user’s manual
; BKP60 banana plug type-K
thermocouple (models
252s, 255s & 257s
only)
Optional purchase accessories:
USB interface kit BRUA-20X; Magnetic hanger BMH-01; BKB32
banana plug to type-K socket plug adaptor
Electrical Specification
Accuracy is given as +/- (% of reading number of digits) or otherwise specified @ 23
o
C +/-
5
o
C and less than 75% R.H.
True RMS Model
257s
ACV & ACA accuracies are specified from 5 % to 100 % of range or
otherwise specified. Maximum Crest Factor <3:1 at full scale & <6:1 at half scale, and with
frequency components fall within the meter specified frequency bandwidth for non-sinusoidal
waveforms
AC Voltage
RANGE
Accuracy
50Hz ~ 400Hz
60.00mV, 600.0mV
1.0% + 5d
6.000V, 60.00V, 600.0V,
1000V
CMRR: >60dB @ DC to 60Hz, Rs=1k
Input Impedance: 10M
, 50 pF nominal
AutoCheck
TM
_ACV (model
255s & 257s
only)
RANGE
Accuracy
50Hz/60Hz
1.000V ~ 1000V
1.4% + 5d
AutoCheck
TM
Lo-Z ACV Threshold:
> 1V nominal
AutoCheck
TM
Lo-Z ACV Input Impedance:
Initially approx. 2.5k
, 120pF nominal;
Impedance increases abruptly within a fraction
of a second as display voltage is above 50V
(typical). Ended up impedances vs display
voltages typically are:
15k
@100V
100k
@300V
250k
@600V
375k
@1000V
Ohm
RANGE
Accuracy
600.0
, 6.000K
, 60.00K
,
600.0K
0.5%+4d
6.000M
0.7%+4d
60.00M
1.2%+4d
Open Circuit Voltage: 0.45VDC typical
DC Voltage
RANGE
Accuracy
60.00mV
0.4%+5d
600.0mV
0.2%+3d
6.000V, 60.00V, 600.0V,
1000V
NMRR: > 60dB @ 50Hz/60Hz
CMRR: > 100dB @ DC, 50Hz/60Hz; Rs=1k
Input Impedance: 10M
, 50 pF nominal
AutoCheck
TM
_DCV (model
255s & 257s
only)
RANGE
Accuracy
1.000V ~ 1000V
1.3% + 3d
AutoCheck
TM
Lo-Z DCV Threshold:
> +1.0VDC & < -1.0VDC nominal
AutoCheck
TM
Lo-Z DCV Input Impedance:
Initially approx. 2.5k
, 120pF nominal;
Impedance increases abruptly within a fraction
of a second as display voltage is above 50V
(typical). Ended up impedances vs display
voltages typically are:
15k
@100V
100k
@300V
250k
@600V
375k
@1000V
AutoCheck
TM
_Ohm (model
255s & 257s
only)
RANGE
1)
Accuracy
000.0
~ 60.00M
1.2% + 10d
Open Circuit Voltage: 0.45VDC typical
1)
AutoCheck
TM
Ohm Threshold:
< 10.00M
nominal
