Chapter 5
Specifications
All specifications are subject to change without notice. Typical for 25 °C unless otherwise specified.
All specifications apply to all temperature and voltage input channels unless otherwise specified. Specifications in italic text are guaranteed by design.
Analog input
Table 1. General analog input specifications
| Parameter | Conditions | Specification | |
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| A/D converter type |
| ADS1256, | |
| A/D data rates |
| 3750 samples per second (S/s), 2000 S/s, 1000 S/s, 500 S/s, 100 S/s, | |
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|
| 60 S/s, 50 S/s, 25 S/s, 10 S/s, 5 S/s, 2.5 S/s | |
| Throughput |
| | Single channel: 2.5 Hz to 1102.94 Hz, software selectable |
|
|
| | Multiple channels: 0.16 Hz to 1102.94 Hz, software selectable |
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| ||
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| |
| Number of channels |
| Up to 32 channels individually | |
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| ended or differential | |
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| Thermocouples require differential mode. For each channel | |
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|
| configured as differential, you essentially lose one | |
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| channel. You can add channels by connecting to an | |
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| ||
| Input isolation |
| 500 VDC minimum between field wiring and USB interface | |
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| |
| Channel configurations |
| Temperature sensor input, s/w programmable to match sensor type | |
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| Voltage input | |
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| Input voltage range | Thermocouple mode | ±0.078125 V | |
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| |
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| Voltage mode (Note 1) | ±20 V, ±10 V, ±5 V, ±2.5 V, ±1.25 V, ±0.625 V, ±0.3125 V, | |
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| ±0.15625 V, ±0.078125 V, | |
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| Absolute maximum | | ±30 V maximum (power on) | |
| input voltage | GND | | ±10 V maximum (power off) |
| Input impedance |
| | 2 GΩ (power on) |
|
|
| | 390Ω (power off) |
| Input leakage current |
| ±10.6 nA | |
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| |
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| Input voltage >±30 V | ±1 µA maximum | |
|
| (power on/off) |
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| Input capacitance |
| 590 pf | |
| Maximum working | Voltage mode: ±20 V | ±20.01 V maximum | |
| voltage (signal + | range |
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| common mode) | Voltage mode: all other | ±10.25 V maximum | |
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| voltage input ranges |
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| Common mode | Thermocouple mode, | 110 dB | |
| rejection ratio (Note 1) | (fIN = 60 Hz) |
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| Voltage mode,(fIN = | 90 dB | |
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| 60 Hz, all input ranges) |
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| ADC resolution |
| 24 bits | |
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| Crosstalk | Adjacent channels | 100 dB | |
| Input coupling |
| DC | |
| Channel gain queue | Up to 64 elements | ||
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| 45 minutes minimum | ||
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| Open thermocouple |
| Automatically enabled when the channel is configured for a | |
| detect |
| thermocouple sensor. | |
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| 25 |