• Display Calibrated in Engineering Units (°C, °F, °K, etc.)
• Proportional to any Thermocouple
• Input Cold Junction Compensated
• Fully Isolated Output and/or 0, 1, or 2 Alarms (Optional)
• Alarm Setpoints Adjustable without Disturbing Transmitter Output
• Fail-Safe Alarm Operation
• LED Alarm Status Indicator
• Adjustable Deadband
• 5 mV Minimum Input Span
• Unlimited Choice of Input / Output Ranges (Within specified range limits)
• Upscale Burnout Protection (Downscale Available)
• Analog and Digital Linearization Options Available
• Fits Standard 1/8 DIN Cutout
• Rated NEMA-4, Splashproof when Properly Installed
• 5 Year Warranty

The DIS874 provides a display, optional isolated DC output voltage or current proportional to any thermocouple input signal, and optional alarm setpoints. All Wilkerson products are designed with RFI filters and lightning protection to reduce susceptibility to electrical noise and damage by lightning. 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 behaves as though the input goes offscale high. Option B provides downscale burnout protection (unit behaves as though the input goes low).

Standard DIS874 and DIS974 provide thermocouple linearization using analog circuitry, which has certain limitations. Its 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.

INPUT RANGE select any type thermocouple (minimum span 5 mV) OPTIONS SA, DA SETPOINT each alarm 0 to 100% of span DEADBAND 0.25% to 100% of span 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 OPTION TX 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 (1200 ohms max at 20 mA) OUTPUT RIPPLE (Peak-to-Peak) <0.1% of span ISOLATION Output / Input >500 megohms Breakdown Voltage >600 VAC rms RESPONSE TIME (Range Dependent) <100 ms

OPEN SENSOR INDICATION > full scale ACCURACY ±0.1% of span at endpoints LINEARITY Standard - See Table Below COMMON MODE REJECTION 120 dB, DC to 60 Hz DISPLAY Digit Size .56" LED, 3½ digits, ±1999 Decimal Point ±1.9.9.9 Control Range Zero ±1999 Span min span 10/max span 2000 DISPLAY Update 3/sec OPERATING TEMPERATURE 14°F to 140°F/-10°C to 60°C TEMPERATURE STABILITY ±(0.02% of span + 1.3 μV)/°C max POWER 115 VAC ±10%, 50 or 60 Hz (4 W max) 230 VAC ±10%, 50 or 60 Hz (4 W max)

 

DIS874/974 STANDARD LINEARIZATION ACCURACY, BASE-METAL THERMOCOUPLES
T/C TYPE	ZERO BASED RANGES		LOW TEMP RANGES (HIGH END = 0°C)
	LIMIT FOR ±1% OF SPAN	LIMIT FOR ±2% OF SPAN	LIMIT FOR ±5% OF SPAN
E	0/500°C 32/392°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 Cannot linearize Type K Above 800°C (1472°F)		-100/0°C -148/32°F
N	0/500°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
DIS874 AND DIS974 LINEARIZATION ACCURACY, PLATINUM THERMOCOUPLES
T/C TYPE	ZERO BASED RANGES		ELEVATED-ZERO RANGES
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 & 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)

Terminal 1 Terminal 2 Terminal 3 Terminal 4 Terminal 5 Terminal 6 Terminal 7 Terminal 8 Terminal 9 Terminal 10 Terminal 11 Terminal 12 Terminal 13 Terminal 14

Output - Output + No Connection T/C Input + T/C Input - Shield (Common) Alarm 1 NC Alarm 1 C Alarm 1 NO Alarm 2 NC Alarm 2 C Alarm 2 NO Power AC L1 Power AC L2