Continuous Monitoring – Three Or More Points

Click here for our budget-priced two point LD systems

For monitoring at two or more locations, we are proud to present the product line that is the talk of the industry — Interscan’s exclusive Automation-Based^™ Gas Detection Systems.

Now, you can specify a system with the exact operation you need, with no compromise. Our new design makes this possible.

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Built around a programmable logic controller (PLC), sensors,and an operator interface (or PC), the features are limited only by your imagination.

Naturally, we can supply a system for any of the gases detected by our own sensors — but that’s only the beginning. Since any sensor with an analog or discrete output connects to the PLC, you can mix and match toxic, combustible and process sensors — yours, ours, theirs — without worrying about anybody’s proprietary controller.

Will you have hundreds of sensors? Do you need an elaborate control scheme, or data acquisition with live and historical trending? Not a problem.

If you can describe it, we can do it.

Check out the standard features on Interscan’s PLC Series Multipoint Gas Monitoring Systems

Dedicated sensor, sample pump, and stainless steel rotameter for each point
All control and display functions at easy-to-use operator interface
User adjustable low and high alarm set points, activating dedicated relays for each monitoring channel
Stackable tower lights for low, high, and fault alarms, and piezoelectric horn for high alarm, common to all channels
Alarm event and time of occurrence tracking, plus last time calibrated tracking, specific for each sensor
Vacuum fault detection and fault display, for all sample pumps
4–20 mA analog output, for each channel

Options

Alternative packaging, including Type X or Type Z purged enclosures and RFI resistant enclosures
Enclosure heating and cooling
Triple alarm set points
Loss of power alarm
Aspirator (in lieu of pump)
Auto zero
Sensor protection circuit

Additional Specs

Measuring Range	Resolution
0–2000 ppm	1 ppm
0–1000 ppm	1 ppm
0–500 ppm	1 ppm
0–200.0 ppm	0.1 ppm
0–100.0 ppm	0.1 ppm
0–50.0 ppm	0.1 ppm
0–20.0 ppm	0.1 ppm
0–5.00 ppm	0.01 ppm
0–2.00 ppm	0.01 ppm
0–1.00 ppm	0.01 ppm
NOTE: Not all measuring ranges are available for all gases. Please refer to specific ordering information, below.

Weight

2-point system 70 lb (31.8 kg)
3-point system 142 lb (64.4 kg)
4-point system 148 lb (67.1 kg)
5-point system 155 lb (70.3 kg)

Dimensions

2-point system:
22″ H x 18″ W x 8.5″ D
(610 x 508 x 203 mm)

3, 4, and 5-point systems:
36″ H x 30″ W x 8″ D
(914 x 762 x 203 mm)

Dimensions given are exclusive of alarm signals and enclosure mounting feet.

Specifications common to all Interscan gas detection instruments

Ordering Information:

PLC Series Multipoint Continuous Gas Monitoring Systems

Click here for our two point systems Click here for multipoint sequential systems

Determine the desired number of points for the model number prefix, and the desired range for the model number suffix.
For example, a four point CO system, with range 0–200.0 ppm, would be PLC414-200.0m

GAS	Number of points	Model No. Prefix	Measuring Range (ppm)	Model No. Suffix
Br₂ bromine	three four five	PLC370 PLC470 PLC570	0–20.0 0–5.00	–20.0m –5.00m
CO carbon monoxide	three four five	PLC314 PLC414 PLC514	0–2000 0–200.0 0–100.0 0–50.0	–2000m –200.0m –100.0m –50.0m
Cl₂ chlorine	three four five	PLC334 PLC434 PLC534	0–20.0 0–5.00	–20.0m –5.00m
ClO₂ chlorine dioxide	three four five	PLC333 PLC433 PLC533	0–20.0 0–5.00 0–2.00	–20.0m –5.00m –2.00m
C₂H₄ ethylene	three four five	PLC307 PLC407 PLC507	0–2000 0–200.0 0–20.0 0–5.00	–2000m –200.0m –20.0m –5.00m
EtO ethylene oxide	three four five	PLC320 PLC420 PLC520	0–50.0 0–20.0 0–5.00	–50.0m –20.0m –5.00m
HCHO formaldehyde	three four five	PLC316 PLC416 PLC516	0–20.0 0–2.00	–20.0m –2.00m
H₂NNH₂ CH₃NHNH₂ (CH₃)₂NNH₂ hydrazine(s)¶	three four five	PLC318 PLC418 PLC518	0–20.0 0–2.00	-20.0m –2.00m
H₂ hydrogen	three four five	PLC302 PLC402 PLC502	0–2000 0–500	–2000m –500m
HBr hydrogen bromide	three four five	PLC380 PLC480 PLC580	0–20.0 0–5.00	–20.0m –5.00m
HCl hydrogen chloride	three four five	PLC336 PLC436 PLC536	0–20.0 0–5.00	–20.0m –5.00m
HCN hydrogen cyanide	three four five	PLC328 PLC428 PLC528	0–50.0 0–20.0 0–5.00	–50.0m –20.0m –5.00m
H₂O₂ hydrogen peroxide	three four five	PLC309 PLC409 PLC509	0–1000 0–200.0 0–50.0 0–5.00	–1000.0m –200.0m –50.0m –5.00m
H₂S hydrogen sulfide	three four five	PLC317 PLC417 PLC517	0–500 0–200.0 0–20.0 0–1.00	–500m –200.0m –20.0m –1.00m
NO nitric oxide	three four five	PLC354 PLC454 PLC554	0–2000 0–200.0 0–20.0 0–5.00	–2000m –200.0m –20.0m –5.00m
NO₂ nitrogen dioxide Also known as N₂O₄ nitrogen tetroxide	three four five	PLC315 PLC415 PLC515	0–2000 0–200.0 0–20.0 0–5.00	–2000m –200.0m –20.0m –5.00m
O₃ ozone	three four five	PLC348 PLC448 PLC548	0–50.0 0–20.0 0–5.00	–50.0m –20.0m –5.00m
PrO propylene oxide	three four five	PLC332 PLC432 PLC532	0–50.0 0–20.0 0–5.00	–50.0m –20.0m –5.00m
SO₂ sulfur dioxide	three four five	PLC324 PLC424 PLC524	0–200.0 0–50.0 0–20.0 0–5.00	–200.0m –50.0m –20.0m –5.00

¶ There is not a separate analyzer available for each of these compounds, and the sensor does not respond equally to all hydrazine species. The analyzer must be calibrated with the specific hydrazine compound of interest.
Special ranges available on request—The panel meter can be factory programmed to display any desired full scale range, within the measuring capability of the instrument.
Although the above table only goes up to five point systems—for reasons of clarity and brevity—there is no limitation on the number of points available. Many larger systems have been supplied. Please contact us for further details.

SQ Series Multipoint Sequential Gas Monitoring Systems

For many toxic gas detection applications—especially carbon monoxide monitoring in parking garages and tunnels—stream-switching or sequential monitoring of the many sample points is a cost-effective, safe, and viable approach. The SQ Series feature:

PLC-based operation, with all user input and display at a color touchscreen, provided with a comprehensive help facility, and many logging functions
Three user-adjustable alarm levels, activating dedicated contact closures
Two 4-20mA outputs: One for the gas concentration, the other identifying the point currently being sampled
Sample draw functionality via two heavy-duty diaphragm pumps. One draws the current sample, the other pulls “pre-sample” air into the system one point ahead of the sample point being monitored, thus providing fresh sample to the sensor at each sequential point advance.
Flow sensor monitoring of each sample line—enabling flow rate display at the touchscreen and fault indication should a line encounter a flow restriction
Auto-zero, with auto-calibrate an option
Sample point dwell times individually adjustable, with point selection for continuous monitoring and removal from sequence selectable at the touchscreen
Serial output from the PLC—ideal to input building management systems, for gas concentration-based ventilation control

Check out the SQ Series operations manual for detailed information and contact us for further specs and pricing.

System Photos

This is a five point sulfur dioxide monitoring system, sampling all points on a continuous basis, used in an industrial plant. Equipped with the features as mentioned above, this unit illustrates the typical appearance of our PLC Series Multipoint Monitoring Systems.

This is a custom-designed carbon monoxide monitoring system that sequentially samples eight points in a vehicular tunnel, with the object of ventilation control. Some of the features include automatic calibration, three levels of alarm individually settable for each point, sample point enable/bypass, sequence override, and a fully adjustable alarm delay/fan control package.

This is the panel of an eight point carbon monoxide monitoring system, sampling all points on a sequential basis, installed in a large underground parking garage.

This is a custom-designed 32-point continuous carbon monoxide monitoring system. The enclosure on the right with the touchscreen houses the sensors and control. The other enclosure contains the sample pumps and filters.

This system is dual purpose, monitoring employee exposure, as well as controlling ventilation—in conjunction with a building management system.

Arc-Max^® data acquisition/archiving/reporting was also provided, along with a remote alarm annunciator.

Larger pictures and more views are available here.

More tech details are available here.

Continuous Monitoring — Multipoint Applications