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Provides 3 1/2 Digit Display, Red or Green LEDs |
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Display Calibrated in Engineering Units (°C,°F,°K, etc.) Proportional to any Thermocouple Output |
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Input Cold Junction Compensated |
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Fully Isolated Output and/or 0, 1, or 2 Alarms (Optional) |
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Alarm Setpoints Adjustable Without Disturbing Transmitter Output |
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Fail-Safe Alarm Operation |
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LED Alarm Status Indicator |
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Adjustable Deadband |
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4 mV Minimum Input Span |
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Unlimited* Choice of Input/Output Ranges |
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Upscale Burnout Protection (Downscale Available) |
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Analog and Digital Linearization Options Available |
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Fits Standard 1/8 DIN cutout |
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Rated NEMA-4X, Splashproof and Corrosion Resistant When Properly Installed |
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5 + 5 Year Warranty |
Description
The DIS874 provides a display, optional isolated DC output voltage or current proportional to any thermocouple input signal, and optional alarm setpoints. The units include filtering and conditioning to reduce susceptibility to transients and noisy operations. The digital display utilizes an auto-zero dual-slope integrating A/D converter for accuracy and stability.
All controls are accessible by removing the gasketed front access panel. The display controls are wide ranging so that they can be calibrated to display engineering units. Decimal point selection is made with a switch, also accessible from the front. A complete set of engineering unit labels is sent with each DIS. Once the display has been adjusted to read the correct engineering units, the alarm setpoints can be adjusted without test equipment and without disturbing the output voltage or current.
Either setpoint may be displayed by use of the SP CAL switch. Each setpoint has an LED to indicate alarm status. The alarms have adjustable deadbands. Terminations are made to a screw terminal connector on the rear of the case.
Upscale burnout protection is provided as standard. In the event the thermocouple opens, the unit responds as thought the input is offscale high. Option B provides downscale burnout protection (unit responds as though the input is low).
The standard DIS874 and DIS974 provide thermocouple linearization using analog circuitry, which has certain limitations. Analog linearization specifications are summarized in Table 1. Option LL, digital linearization, provides superior performance as listed under the specifications.
Typical Applications
Temperature indication, monitoring, control, data acquisition, HI/LO control, etc.
Mounting
The DIS is designed to be mounted from the front of a panel through a standard horizontal 3.62 x 1.77 inches (1/8 DIN) cutout. Two mounting cam-screws secure the DIS to the panel.
Specifications
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INPUT RANGE
select any type thermocouple
(minimum span 4 mV)
OUTPUT RANGE
Voltage
select any range between ±10 V
10 mA max load
(min span 0.2 V)
Current
select any range from 0 to 20 mA max
24 V compliance**
(min span 1 mA)
OPEN SENSOR OUTPUT
>= full scale
RELAY CONTACTS (spdt)
Resistive Load:
5 A max, 150 W max,
240 VAC max, 30 VDC max
Inductive Load:
1/8 HP max at 120/240 VAC
SETPOINT
each alarm 0 to 100% of span
DEADBAND
0.25% to 100% of span
RESPONSE TIME
<= 100 ms
(range dependent)
ISOLATION
Output/Input
>500 megohms
Breakdown Voltage
>600 VAC rms
POWER
115 VAC ±10%, 50/60 Hz
(4 W max)
230 VAC ±10%, 50/60 Hz
(4 W max)
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DISPLAY
Digit Size
.56 inch LED, 3 1/2 digits, ±1999
Decimal Point
±1.9.9.9
Control Range
Zero
±1999
Span
min span 10
max span 2000
Display Update
3/sec
ACCURACY
±0.1% of span
LINEARITY
Standard
See Standard Linearization Tables Below
Option LL
±2°C (3.6°F) or better
±0.05°C (0.9°F) for types
J, K, T, E or N if range is
between -200 and +200°C
(-328 and +392°F)
OUTPUT RIPPLE
<0.1% of span
(peak to peak)
COMMON MODE REJECTION
120 dB, DC to 60 Hz OPERATING TEMPERATURE
14°F to 140°F
-10°C to 60°C
TEMPERATURE STABILITY
±(0.02% of span +30 µV)/°C max
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| STANDARD LINEARIZATION ACCURACY, BASE-METAL THERMOCOUPLES
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| ZERO-BASED RANGES
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LOW-TEMP RANGES
(HIGH END 0°C)
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T/C
TYPE |
LIMIT FOR
±1% OF SPAN |
LIMIT FOR
±2% OF SPAN |
LIMIT FOR
±0.5% OF SPAN |
| E |
0/500°C
32/932°F |
0/1000°C
32/1832°F |
-100/0°C
-148/32°F |
| J |
0/1000°C
32/1832°F |
0/1200°C
32/2192°F |
-100/0°C
-148/32°F |
| K |
0/800°C
32/1472°F |
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-100/0°C
-148/32°F |
| Cannot Linearize Type K Above 800°C (1472°F) See Option LL above |
| N |
O/500°C
32/932°F |
0/1200°C
32/2192°F |
-100/0°C
-148/32°F |
| T |
0/400°C
0/752°F |
0/400°C
0/752°F |
-100/0°C
-148/32°F |
| STANDARD LINEARIZATION ACCURACY, PLATINUM THERMOCOUPLES
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T/C
TYPE |
ZERO-BASED RANGES
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ELEVATED-ZERO RANGES
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| B |
-N.A.- |
±3% of span for
500/1820°C (932/3308°F)
±1.5% of span for
800/1820°C (1472/3308°F) |
| R |
±2.5% of span or better,
any zero-based range |
±1.5% of span or better, any
range starting above 200°C (392°F) |
| S |
±2.5% of span or better,
any zero-based range |
±1.5% of span or better, any
range starting above 200°C (392°F) |
* Within specified range limits.
** Compliance: The sum of the voltage drops in the output loop cannot exceed 24 V at rated current
(1200 ohms at 20 mA).
