ENOTEC SILOTEC ® Installation and Operation Instructions for 8000 Silo Monitoring O ₂/CO ₑ Analyzer System

ENOTEC SILOTEC ® Installation and Operation Instructions for 8000 Silo Monitoring O ₂/CO ₑ Analyzer System

ENOTEC has developed an extraction based O ₂/CO ₑ (carbon monoxide equivalent) analysis system specifically for silo inerting and smoldering fire warning. It is used in dust explosion-proof areas and is based on the SME5 series electronic hardware. It can detect CO, H ₂, hydrocarbons, and identify the risk of smoldering fire inside silos. It is one of ENOTEC's three product lines, alongside COMTEC6000 and ENSITU7000.

Preface, Symbols and General Safety Principles

Product background: ENOTEC has been producing gas analyzers since 1980, following ISO9001 quality control; SILOTEC8000 achieves redundant monitoring of oxygen and combustible components, identifying smoldering fires in silos: a decrease in O ₂ and an increase in CO ₑ indicate smoldering fires.

Mandatory safety regulations

The equipment uses mains power, and when opening the cover, the power must be cut off. Only authorized personnel are trained to operate;

It is strictly prohibited to directly connect the probe to 230V mains power, as it may directly burn out the probe heater;

When the working shell temperature of the measuring pool (cuvette) is greater than 100 ℃, insulated gloves must be worn for disassembly; Cut off the power supply of the entire machine before dismantling, cool it down to below 35 ℃ before operation;

It is recommended to maintain powered operation during equipment shutdown; Frequent start stop cycles can cause thermal fatigue and shorten the lifespan of heaters, thermocouples, and sensors;

Storage conditions: Dry and ventilated at -40~+80 ℃, away from paint mist and silicone sprays;

CO ₑ sensor measurement premise: Process O ₂ ≥ 0.3%, oxygen concentration below this value, CO ₑ measurement error significantly increases.

Explosion proof positioning: The probe is installed inside the dust explosion-proof silo in Zone 20; The probe junction box is located in Zone 22; The electronic unit is arranged in the safe zone or Zone 22.

System Description

2.1 System composition

The whole set is divided into: electronic unit SME-53 (on-site wall mounted IP66)/SME-54 (19 inch rack IP20), GRP fiberglass shell silo probe SIL-KES-0001, signal cable FEP-0007/0008, pneumatic pipeline FEP-0002. Probe built-in: 3 μ m porous filter element (isolating silo 20 zone from heating sensor), jet extraction unit, measuring tank (simultaneously installing O ₂ zirconia sensor+CO ₑ catalytic sensor); Optional blow back component for automatic cleaning of sampling filters.

Operating condition boundary: maximum silo pressure of 0.5 bar; The maximum temperature of process gas at the probe is 100 ℃; Electronic unit environment -20~+55 ℃; Probe environment -20~+55 ℃.

2.2 Measurement principle

O ₂ (Zirconia): The internal sensor of the probe is heated, and instrument air (20.95% O ₂) is introduced into the reference side. According to the Nernst equation, mV signals are generated from the oxygen partial pressure on both sides to convert the oxygen concentration; The airtight isolation of reference gas and sample gas is crucial.

CO ₑ catalytic sensor: The catalytic electrode oxidizes combustible gases (CO, H ₂, C ₓ H ᵧ) to generate a voltage signal and output CO equivalent.

Fire warning logic: In the event of smoldering in the silo, fuel oxygen consumption, decrease in O ₂, and synchronous increase in CO ₑ, the system can promptly sound an alarm.

2.3 Nameplate Information

The nameplate includes: power supply voltage, current, protection level, year of manufacture, serial number, and order code; Divided into electronic unit nameplate and GRP probe housing nameplate. The GRP probe housing contains gas path components such as injectors, flow meters with alarm modules, O ₂/CO ₑ measuring cells, sampling probes, purge solenoid valve groups, throttle valves, etc.

Installation

3.1 Installation requirements for electronic units

IP66， Avoid vibrations greater than 2g; Reserve a minimum installation gap around the perimeter, and it is recommended to install it at eye height;

The user side must be equipped with an independent external power circuit breaker, located close to the equipment and clearly labeled;

The wiring terminal is compatible with a wire diameter of 0.08-2.5mm ²; Cut off the mains power before opening the cover, restore the casing and then power it on again.

3.2 Probe signal cable FEP-0007/0008

The shielding layer is only allowed to be grounded at a single point on the PE terminal of the electronic unit, and the probe end is strictly prohibited from being grounded;

The maximum cable length is 50m, and the minimum bending radius is specified; Original compensating thermocouple cables must be used;

The cable includes: O ₂ measuring unit, two thermocouples, probe heater, probe solenoid valve, CO ₑ sensor;

Cable and power cable are vertically crossed and routed; It is necessary to install a matching ferrite magnetic ring, otherwise CE compliance will be invalidated.

3.3 Installation of probe body (cylinder side)

The top plate of the silo is perforated and welded with flanges, which must be airtightly welded; The installation torque of the sampling filter is 250Nm, and it must be confirmed that the seal is reliable;

GRP probe housing protection IP65; Avoid>2g vibration, ambient temperature -20~+55 ℃;

The GRP shell PE terminal must be connected to the silo protection ground by the customer.

3.4 Pneumatic Pipeline FEP-0002

Instrument air input pressure: 2-10 bar, meeting ISO8573-1 Class 2 quality standards;

The bending radius of the pipeline is specified, and the joint is equipped with a support sleeve and a clamp nut;

Air interface: instrument air intake, standard air input and output, reference air output;

Optional blowback module: 4L blowback air storage tank, solenoid valve timing control; Automatically triggering blowback when traffic falls below the threshold; Backblowing simultaneously cuts off the air path to the sensor, and compressed air rushes into the silo to clean the sampling filter.

Initial operation

4.1 Pre operation checklist

Match the probe with the electronic unit system number; The nameplate voltage is consistent with the power supply;

There is no leakage in electrical wiring and pneumatic pipelines; Flange welding is airtight, and gasket bolts are in place; The on-site working conditions meet the specifications.

4.2 Power on

Connect the mains power and set the language, date and time, TAG device tag number, ENOTEC REMOTE remote code, and probe cable length in sequence (parameter errors can cause measurement errors or even burn the CO ₑ sensor). Power on timing: O ₂ sensor heating stage → CO ₑ sensor heating stage → normal measurement mode.

The instrument air will only be turned on after power on, and the air circuit is locked before power on to protect the sensor.

Panel status LED: Orange Alarm Alarm, Orange Maint Maintenance Mode, Red Error System Fault; Factory system password 0000.

Software menu

The menu is divided into SYS-MENU system menu, system check menu, and CAL-MENU calibration menu.

5.1 SYS-MENU system menu

System Information Page: Real time O ₂, CO ₑ measurement values, mA output, sensor raw mV, various temperatures, heater power, sensor lifespan, full calibration history, operating time, software version.

System Configuration

O ₂, CO ₑ range configuration, linear mapping 4-20mA output; Output 3.6mA below the lower limit and 20.4mA above the upper limit; customizable fault mA output for system faults;

High and low limit alarm, supporting hysteresis setting; Average filtering time for measured values; Wet to dry basis conversion;

Sensor calibration parameters (offset, slope, offset/Alpha/Beta/Gamma/Delta/SO ₂ correction for CO ₑ, certificate attached to each CO ₑ sensor);

Calibration time parameters: pre blowing time, duration of standard gas injection, process delay; ACAL automatic calibration (triggered by timing/digital input, supports 1-point and 2-point calibration; 2-point calibration requires permanent connection to the calibration cylinder);

ENOTEC REMOTE wireless Bluetooth: up to 16 mobile phones/tablets can be connected simultaneously, and the transmission distance can be set (short/medium/maximum);

Measurement unit, multilingual, changing system password, restoring factory settings, CO ₑ measurement switch.

Before replacing the CO ₑ sensor, the software must set the CO ₑ to OFF; After replacement, enter all parameters of the sensor certificate in full; Parameter error directly burned the CO ₑ sensor.

System check menu: Sensor calibration, mA output circuit calibration, relay output calibration, digital input status reading.

CAL MENU calibration menu

Supports manual 1-point calibration (offset only), 2-point calibration (offset+slope), and can calibrate O ₂, CO ₑ separately, or both simultaneously;

The test air has a fixed value of 20.95% O ₂, which is built-in to the system and does not require manual input;

The calibration interface displays trend curves, flow rates, and progress bars; Two point calibration requires the introduction of a second bottle of calibration gas.

Maintenance and repair

High temperature component operations must be powered off, wait for sufficient cooling, and wear insulated gloves.

Fuse replacement: Power off, the document provides all insurance specifications (F1-F6).

Air flow regulation

The instrument air supply pressure is 2-10 bar, and if the pressure is greater than 6 bar, the flow rate needs to be readjusted;

Test air flow rate: 60-80 l/h; Sample gas extraction flow rate: 40-80 l/h;

Differentiate the position of the regulating valve between SME-53 wall mounted and SME-54 19 inch rack mounted models.

Core component replacement process

Sampling filter: regular inspection, installation torque 250Nm;

Disassembly of measuring pool (cuvette): First, turn off CO ₑ measurement and power off the whole machine; Disconnect the electrical terminals and gas circuit, loosen the fasteners and remove them;

Replacement of probe internals, O ₂ sensors, and CO ₑ sensors; Replacing the CO ₑ sensor requires entering all calibration parameters into the certificate; The sensor needs to be removed for a long time, and the conduit needs to be sealed with a sealing kit to prevent air from entering the environment;

Optional blow back

When the sampling flow rate is below the alarm threshold, automatic blowback will be initiated; Continue measuring once the backflow is completed and the flow rate is restored; Continuous low traffic triggers system failure alarm;

Backblowing will also be performed during each calibration and sensor verification; Can be triggered in conjunction with ACAL automatic calibration cycle.

Relay output definition: system fault (normally closed), maintenance status, range switching, probe valve, two-way limit alarm; The probe valve relay supports up to 230VAC.

Status messages and troubleshooting

7.1 Classification of Fault Information

Error messages: Hardware failure, thermocouple open circuit, probe temperature not reaching set, sensor open circuit, calibration failure, insufficient sample gas flow rate, CO ₑ board communication failure, CO ₑ heating short circuit/open circuit, REMOTE module hardware failure; Trigger the system fault relay and switch the mA output to the fault setting value.

Alarm message: O ₂/CO ₑ limit alarm, high or low environmental temperature of electronic unit, low clock battery voltage.

Maintenance message: Measurement values are maintained during calibration.

7.2 Typical Fault Phenomena

Common Causes of Fault Phenomena

Poor connection of O ₂ reading fluctuation wiring; Filter blockage/leakage; Flange seal failure

The O ₂ reading is too high, and there is a leak in the probe and flange, causing ambient air to seep into the air path

O ₂ displays close to 0% heater damage, thermocouple failure, fuse burnout, cable breakage; A large amount of reducing gases inside the silo; The O ₂ sensor is damaged

O ₂ is high, CO ₑ is low, CO ₑ sensor conduit seal failure, external air infiltration

No CO ₑ reading exceeds the physical range; CO ₑ sensor hardware failure; Process O ₂ ＜ 0.3%

Sample gas flow failure alarm filter blockage; Instrument air loss; Pneumatic pipeline damage; Traffic alarm threshold setting error

Hardware cannot repair faults on its own, please contact ENOTEC after-sales service.

Technical specifications, drawings, spare parts, warranty

8.1 Key Technical Parameters

SME-53 electronic unit (wall mounted)

Protection IP66; SME-54 rack version IP20; Backlit dot matrix LCD, thin film buttons;

O ₂: 2 sets of freely configurable range 0-2%~0-25% Vol; Accuracy<0.5% reading or 0.02Vol% O ₂;

COₑ：0‑5000ppm；

Power supply 115/230V AC; Heating power consumption 425VA, normal measurement 225VA;

Output: Isolated active 4-20mA; relay contact 24V 1A (probe valve supports 230V 1A).

Probe SIL-KES-0001

The maximum process temperature is 100 ℃; Pressure ± 50mbar; IP65；

O ₂ T90 response<5s; used for dust zone 20;

Material: 316 stainless steel, GRP fiberglass shell.

Air source requirements: Instrument air ISO8573-1 Class2; Particles ≤ 1 μ m, oil ≤ 0.1mg/m ³, pressure dew point -20 ℃; Input pressure 2-10 bar; The maximum input pressure of the standard gas cylinder is 3 bar.

8.2 Spare parts and drawings

Including electronic unit and probe outline drawings; Complete set of spare parts BOM: sampling filter, flowmeter, pressure regulating valve, solenoid valve, measuring tank, injector, gas storage tank, display motherboard, power board, CO ₑ board, etc.

8.3 Warranty and Compliance Statement

The whole machine is guaranteed for 24 months; Spare parts warranty for 12 months; Frequent start stop of the heater is prohibited, and damage caused by frequent cold and hot cycles is not covered by the warranty.

EU compliance: Meets ATEX 2014/34/EU, EMC, LVD, RoHS; The probe is used for dust zone 20 and GRP housing zone 22, with a maximum surface temperature of 90 ℃ for components in contact with dust.