技术资料.pdf - 第41页

41 DC operating characteristics 4 Function Digits 5 Readings / s Additional R MS noise error DCV 7 , DCI, and R esistance (≤10 kΩ) 6½ 6½ 5½ 5½ 4½ 4½ 0.6 (0.5) 6 (5) 60 (50) 300 600 3000 0% of rang e 0% of rang e 0.001% o…

Input protection

1.5 A 250 Vac fuse on 34921A module

True RMS AC current

Measurement method

Direct-coupled to the fuse and shunt. AC coupled True RMS measurement

(measures the ac component only

Shunt resistance

5 Ω for 10 mA; 0.1 Ω for 100 mA, 1 A

Input protection

1.5 A 250 Vac, 50/60 Hz fuse on 34921A module

Thermocouple

Conversion

ITS-90 software compensation

Reference junction type

Internal, fixed, or external

Open thermocouple check

Selectable per channel. Open > 5 kΩ

Thermistor

44004, 44007, 44006 series

RTD

a = 0.00385 (DIN) and a = 0.00392

Measurement noise rejection 60/50 Hz

DC CMRR

AC CMMR

140 dB

70 dB

Integration time Normal mode rejection

200 plc/3.33 s (4 s)

100 plc/1.67 s (2 s)

20 plc/333 ms (400 ms)

10 plc/167 ms (200 ms)

2 plc/33.3 ms (40 ms)

1 plc/16.7 ms (20 ms)

< 1 plc

105 dB

100 dB

95 dB

90 dB

85 dB

60 dB

0 dB

Note:

1. For 1 kΩ unbalance in LO lead

2. For power line frequency ± 0.08%

3. For power line frequency ± 1% use 75 dB or ± 2.5% use 60 dB

DC operating characteristics

Function

Digits

Readings / s

Additional RMS noise error

DCV

, DCI, and Resistance

(≤10 kΩ)

6½

5½

4½

0.6 (0.5)

6 (5)

60 (50)

300

600

3000

0% of range

0.001% of range

0.01% of range

0.1% of range

Autozero OFF operation

Following instrument warm-up at calibration temperature ± 1 °C and < 10 minutes, add 0.0002% range

additional error. +5 μV. (For 300 VDC, instead of .0002% of range, need .00066% of range)

Settling considerations

Reading settling times are affected by source impedance, low dielectric absorption characteristics, and input

signal changes.

AC operating characteristics

Digits

Readings /

AC Filter

ACV, ACI:

6½

7 sec/reading

100

Slow (3 Hz)

Medium (20Hz)

Fast (200 Hz)

Note:

1. Reading speeds for 60 Hz and (50 Hz) operation; autozero OFF

2. 6½ digits = 22 bits; 5½2 digits = 18 bits; 4½ digits = 15 bits

3. Add 20 μV for DCV, 4 μA for DCI, or 20 mΩ for resistance

4. For 300 VDC, multiply the additional noise error by 3.3

5. Maximum reading rates for 0.01% of AC step additional error; additional settling delay required when input DC

level varies

6. 6½ digits = 22 bits; 5½ digits = 18 bits; 4½ digits = 15 bits

7. For external trigger or remote operation using default settling delay (Delay Auto)

8. Maximum limit with default settling delays defeated

General Specifications

System specifications

Scanning inputs

Analog:

34921A, 34922A, 34923A, 34924A, and 34925A multiplexer channels

Digital

34950A/52A digital in and totalize

Scan triggering

Source

Interval, external, button press software, or on monitor channel alarm

Scan count

1 to 50,000 or continuous

Scan Interval

0 0 99 hours; t ms step size

Channel delay

0 to 60 seconds per channel; 1 ms step size

External trig delay

< 2 ms. With monitor on < 200 ms

External trig jitter

< 2 ms

Alarms

Analog inputs

Hi, Lo, or Hi + Lo evaluated each scan

Digital inputs

34950A/52A digital in maskable pattern match or state change

34950A/52A frequency and totalize: Hi limit only

Monitor channel

Alarm evaluated each reading

Alarm outputs

4 TTL compatible. Selectable TTL logic Hi or Lo on fail

Latency

5 ms (typical)

Memory

Type

Volatile

Readings

500,000 with timestamp, readable during scan

States

5 instrument states with user label

Alarm queue

Up to 20 events with channel number, reading, and timestamp

System features

Per-channel

Individual Mx+B scaling and calculated real-time min/max/average

Power fail recovery

Save switch states

Relay maintenance

Counts each relay closure and stores on module. User resettable

Real-time clock

Battery-backed, 20-year typical life

Line power

Power supply

Universal 100 Vac to 240 Vac

Power line frequency

50 – 60 Hz ± 10% automatically sensed

Power consumption

150 VA

Environment

Operating environment

•

0 - 55°C, 2000 m, maximum humidity is 80% RH at 40˚C and decreases

linearly to 37% RH at 55˚C

•

IEC 60664-1 pollution degree 1 or 2

•

Refer to 34980A User's Guide, Chapter 4, Module Considerations section for

the details of Environmental Operating Limits (current and power dissipation)

for the Plug-In Modules in Pollution degree 1 or 2 environments.

Storage environment

- 40 °C to 70 °C

Note:

1. Storage at temperatures above 40 °C will decrease battery life

2. From 40°C to 55°C, the maximum % Relative Humidity follows the line of constant dew point.