Specifications are subject to change without notice.
IOtech 652u & 655u User’s Manual
978090
Specifications 7.a-3
IEPE bias source:
Current: 4.0mA, 22V compliance (on/off software programmable per channel)
Impedance: >255k
Ω
IEPE fault detection thresholds:
<1V (short), >20V (open)
IEPE fault indication:
Software indicator, per channel
Analog Temperature Measurements
(Temperature Measurement applies to IOtech 655u only)
ADC converter resolution:
24 bits
ADC converter type:
Delta-sigma
Sample rate
: 200msec per conversion
Channels:
5
Input range:
±100mV
Offset voltage:
±5µV
Offset drift:
zero
Gain uncertainty:
±0.05%
Gain drift:
0.005%/°C
Input impedance:
each input to analog ground: 100 Meg
Ω
Open sensor detection current:
50 nA
Common mode range:
±10V
Common mode rejection ratio;
150dB typical
Maximum voltage without damage between inputs:
±5V DC or 5V peak-to-peak AC
Maximum voltage without damage from earth ground to input:
±17V DC or 34Vpeak-to-peak AC
Maximum voltage without damage from RTD excitation high to earth ground or high to RTD
excitation low:
±3V DC or rms AC
Channels may be of mixed type; different TC types and/or RTD
Thermocouples
:
655u TC Measurement Uncertainty (1 sigma °C, Ambient 23°C,
±
15°C, exclusive of TC wire error)
TC Type
Measured Temperature (°C)
-200
-100
0
100
200
300
400
600
800
1000
1200
1400
1600
B
-
-
-
2.94
1.84
1.48
1.49
1.14
1.10
1.05
1.02
1.04
1.03
E
0.91
0.88
0.88
0.88
0.88
0.88
0.89
0.89
0.90
0.92
-
-
-
J
0.92
0.89
0.88
0.88
0.88
0.89
0.89
0.90
0.90
0.92
0.94
-
-
K
0.95
0.89
0.88
0.88
0.89
0.89
0.90
0.91
0.92
0.94
0.96
-
-
N
1.02
0.91
0.89
0.89
0.89
0.89
0.90
0.91
0.92
0.93
0.95
-
-
R
-
-
1.18
1.04
1.04
1.03
1.01
0.99
2.01
1.01
1.01
1.03
1.05
S
-
-
1.18
1.12
1.04
1.03
1.01
1.03
1.02
1.02
1.04
1.06
1.07
T
0.95
0.90
0.88
0.88
0.88
0.89
0.89
-
-
-
-
-
-
RTD Measurement Uncertainty (1 sigma °C, Ambient 23°C,
±
15°C, exclusive of RTD error, assumes 4-wire RTD)
RTD
0.20
0.21
0.24
0.28
0.29
0.40
0.48
0.66
0.92
-
-
-
-
Cold Junction Sensor Accuracy
Ambient Temperature Range (°C)
Max Error (±C)
-40 to -20
1.0
-20 to 0
0.8
0 to 10
0.4
10 to 45
0.2
45 to 60
0.5
RTD
:
Type supported:
PT100, alpha = 0.00385
Excitation:
100mV through 100
Ω
Accuracy (exclusive of RTD error, assumes 4-wire connection):
±0.2°C
Connections:
2, 3, and 4 wire
