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Preferred Instruments

Preferred Instruments manufactures microprocessor based controllers, instruments, and electric actuators for combustion and process applications. Preferred Instruments also manufactures oil tank gauging and leak detection equipment. A major component of the Instrument group sales is from control systems integration and personal computer based Supervisory Control and Data Acquisition systems. Preferred Utilities' industrial factory is located in Danbury, CT

JC-10D Digital Process Monitor

The JC-10D Process Bar Graph Indicator and Alarm Monitor is a microprocessor based indicator alarm that can be field configured for a wide variety of applications including: Boiler Draft, Boiler Drum Level, Tank Levels, and Flow Rates.


The JC-10D is a versatile display monitor with built-in alarm contacts. It accepts a variety of analog input types and provides a bargraph display and alarm contacts. It is ideal for boiler draft, drum level, tank levels, flow rates, operating pressures, temperatures, or any other common process monitoring applications.


The JC-10D Process Indicator is a microprocessor based indicator alarm that can be field configured for a wide variety of applications. The instrument provides a highly visible backlit LCD display with easy to understand bar graph, scaled numeric display, and front panel alarm messages. Bar Graph scaling, alarm setpoints, and time delays are all field selectable.  Adjustments are made directly from the faceplate of the instrument by scrolling through a user friendly, English language menu. The unit is constructed of rugged polymer housing with a gasketed NEMA 4 faceplate.

Versatile: Field selectable input types: 2 or 4 wire 4-20 mADC, 10k Thermistor, J or K Thermocouple, Potentiometer, 0-2.5 VDC, or Pulser. Thermistors and thermocouples are linearized and cold junction compensated. The Numeric display can be scaled to any desired display range from the front panel.  The Bar graph range and scaling can be set independently from the Input scaling. The 4-20 mADC re-transmission output can be scaled independently as well.  

Alarm Sequences: The 2 alarms can be configured as HI-HI, HI, LO, or LOLO alarms with individually adjustable dead bands and Time Delays. Alarm adjustment is done in scaled engineering units, not percentages. The 2 relay outputs can be assigned as to an alarm or as a common alarm output with alarm silencing logic. Each relay can be configured as auto reset or manual reset.


  • RS485 Modbus Communication
  • 4-20 mADC Retransmission
  • 4 Digit Display
  • 200 Segment Bar Graph
  • Large LCD Graphic Display
  • Field Adjustable Using English Language Menus
  • 2 SPDT Relays For Alarms and Events
  • Flow Totalizer


Power Supply: 120 VAC, +/- 15%, 50/60 Hz, 15 VA

Case Size: 8″H x 3.5″W x 7.5″D

Enclosure Type: NEMA 4 Faceplate

Ambient Temperature: +32° to 122° F

Displays: High Contrast LCD Display, 4″ High, 0.5% Resolution Bargraph

Alarm Setpoints: Two (2) Adjustable With Adjustable Time Delays HI-HI, H, L, LO-L Modes, Manual Reset and Alarm Silence Modes 


Input Types: Field Selectable, 4-20 mADC, 100 Ohm Load, Thermistor, -20° to +300° F, Type J Thermocouple, 0-1000° F, Type K Thermocouple, 0-2000° F, Potentiometer, 100 Ohm to 10 Kohm 0-5 VDC

Accuracy: 0.005% Resolution, 0.07% Accuracy

Sensor Power: 24 VDC @ 100 mADC, 15 VDC @ 50 mADC, 2.5 VDC @ 12 mADC 


Relay: Two SPDT Relays 10 A resistive, 8 FLA, ½ HP, 120 VAC

Retransmit: 4-20 mADC, 650 Ohm Load Maximum

Network: 1200 – 38400 Baud; RS485 Modbus, ASCII or RTU 


Provide a remote reading, microprocessor-based Process Indicator and Alarm System to monitor [specify required monitoring point such as boiler draft, drum level, tank level, flow or pressure…]. The instrument shall provide a continuous numeric and 4″, 0.5% resolution (minimum) bar graph display.  The instrument shall contain: dual adjustment alarm setpoints with 10 amp. relay outputs, unique messages and manual reset pushbutton. The Instrument shall be field selectable as 2 or 4 wire 4-20 mADC, 10k Thermistor, J or K Thermocouple, Potentiometer, 0-2.5 VDC, or Pulser. The Instrument shall provide cold junction, and upscale thermocouple break protection for thermocouples, 4-20 mADC and RS485 Modbus remote output signals. The housing shall be panel mountable, fully gasketed with a NEMA 4 front face. All adjustments shall be made from the front panel display in engineering units. No external configurator or laptop shall be required. The instrument shall be manufactured and labeled in accordance with UL508 requirements (CSA C22.2 #14 for use in Canada). Inspection and labeling shall be supervised by UL or other OSHA approved Nationally Recognized Test Lab (NRTL). Indicator and Alarm System shall be Preferred Instruments, Danbury, CT, Model JC-10D.