Opacity Monitor HC-08740A
The Hays Cleveland Model HC-08740A Universal Opacity Monitor provides reliable, continuous measurement of the density of confined particulates such as dust or smoke. It is easy to calibrate and requires no routine maintenance other than occasionally cleaning the sight glass.
- Easy to Use LCD Display
- 4-20 mA 0-100% Opacity Retransmission
- Single Pass Design, No Moving Parts
- Field Adjustable Via Keybad and Jumpers
- Early Warning Message and Relay Contact for Deteriorating Combustion Conditions
- Burner Safety Shutdown Message and Relay Contact
- Alarm Sequences: Standard, NYC/BAR, & Overfire Air
- Overview and Features
- Application
- Specifications
- Documents
The basic system consists of an electronics unit and two breeching components, consisting of a light source that directs a beam through the measured particulate, and a light sensor that receives the beam, detects changes in opacity, and sends a proportional signal to the electronics unit. The wide-beam light source and narrow-view receiver make installation easy because alignment of the breeching units does not need to be precise. The electronics produces a digital readout of percent opacity and a 4-20 mA DC output signal suitable for recording, display, or indication. SPDT contacts are provided for a remote alarm (which can be purchased separately: Preferred Utilities Model: SDA-VB). The operator can select manual or automatic alarm reset. Modbus communications for interface with a SCADA system (Supervisory Control and Data Acquisition system) or other controls is standard. A standard serial printer port is provided. The electronics unit is available in open-mount, surface-mount, and flush-mount formats. It can be installed in any dry, convenient area within 250 feet of the light source and receiver units. The standard model has a vacuum fluorescent display with three status LED’s. There are four LED indicators on units equipped with auxiliary functions.
The Burner Cutoff Auxiliary Function is a delayed-off timer that shuts the burner down if an alarm condition (opacity exceeding 20%) persists for 120 seconds. The timer can be reset manually only after reduction of opacity: it cannot be reset when opacity is above 20%. (This feature meets the requirements of the New York City air pollution control code for alarm and burner control functions). Model A-08740 Opacity Monitors equipped with the burner cutoff function have four LED indicators on the front of the electronics panel, marked Clear, Smoke, Alarm, and Burner Off. In addition, an audible alarm with adjustable trip point and delay is mounted on the front face of the electronics unit.
The Overfire Air Timer Auxiliary Function is a delayed-off timer that provides relay contacts for the control of smoke-reduction air in coal-fired installations. As soon as opacity exceeds the alarm trip point, the relay is energized. It remains energized as long as the alarm condition persists. After the alarm condition is corrected, the relay remains energized for an adjustable period up to five minutes. Model A-08740 Opacity Monitors equipped with the overfire air timer function have four LED indicators on the front of the electronics panel, marked Clear, Smoke, Alarm, and Overfire Air.
The Hays Cleveland HC-08740A Smoke Opacity Monitor assures accurate measurement of the smoke emissions from boilers, incinerators, kilns, and similar sources of intermittent, visible emissions. Typical applications include commercial buildings, schools, hospitals, apartment complexes, and industrial plants. The information provided encourages increased emphasis on clean, efficient combustion and effective air pollution control.
Ordering Information: HC-08740A Opacity Monitor includes: (1) Control board and display with selected mounting option, (1) HC-31180 Light Source, (1) HC-31181 Light Receiver, and (2) HC-27367 4” Sight Glass Assembly.
Power Requirements: 120Vac +/- 10%, 50/60 Hz
Ambient Temperature Ranges: 32-130F (0-54C) for electronics unit. 32-160F (0-70C) for light source and receiver units.
Fuse: 1, @ 1 Amp
Measurement Range: 0-100% Opacity
Retransmit Output Range: 4-20mA dc, 750 Ohms maximum load. Directly proportional to measurement range, where 4mA = 0% and 20mA = 100%. Output is grounded (not isolated).
Resolution: Digital meter reads 0-100% opacity with 1% resolution.
Response Time: 1 second for 90% of actual change in opacity.
Accuracy: +/- 5% opacity under all specified conditions.
Light Source to Receiver Distance: minimum 4ft (1.20m) to maximum 15ft (4.57m).
Light Source Lamp Life: 1 year minimum.
Spectral Response of Photocell: 350 – 1100 nm.
Cable Length: 250ft (76m) maximum.
Indicators:
Green: “Clear” LED.
Yellow: “Smoke” LED and flashing display.
Red: “Alarm” LED and flashing display.
Alarm Timer: adjustable 0-300 second delay.
Alarm Trip Point: adjustable 0-99% opacity.
Alarm Reset: automatic; field convertible to manual.
Alarm Contacts: Isolated SPDT, 10 Amp, 120 V ac resistive, fail safe.
Purge Delay Timer: adjustable 1-600 second delay
NYC Burner Cutoff (optional): fixed 20% trip point and fixed 2-minute (120-second) delay
NYC Burner Cutoff contacts: isolated SPDT, 10 Amp, 120 V ac resistive, fail safe.
Overfire air timer (optional): maintains contact closure after smoke abatement for a period adjustable from 1-300 seconds.
Overfire air contacts: isolated SPDT, 10 amp, 120 V ac resistive, fail safe.
Housing for enclosed models: NEMA 1.
Relative Humidity: 0-90%, non-condensing.
Modbus Communication: RTU. 9600 or 19200 Baud rate. N/8/1 (no parity, 8 data bits, 1 stop bit).
Printer port: RS232 serial port, DB9-M connector, 9600 baud, N81 (no parity, 8 data bits, 1 stop bit).
Output adjustable, generated every 0-60 minutes, where 0 = disabled.
Output format: 5 sequence #, blank space, 3 digit opacity, “%” symbol, carriage return, line feed.
Example: 01234 011% c/r l/f
Shipping Weight: varies with options; these are typical:
Electronics units in enclosures are 7.5-8.5 lbs.
Open-mounted electronics units are 6.5-8.0 lbs.
Light source and receiver, combined, 9 lbs.
Opacity Monitor Specification
Opacity Monitor Instruction Manual
