Det-Tronics PIRECL Infrared Hydrocarbon Gas Detector PointWatch Eclipse User Manual

Page 23

95-8526

14.2

calibRation

Calibration oVerView
Although routine calibration of the Pointwatch Eclipse is

normally not required, the device supports non-intrusive

field calibration capability. Two (2) calibration procedure

options are provided:

1. normal Calibration is a two-step process consisting

of clean air (zero) condition and mid-scale (span)

adjustment. Calibration gas must be applied by

the operator to enable span adjustment. Normal

calibration is required whenever the gas type setting

has been changed from the factory setting (methane,

propane, ethylene, or butane). Purge the Eclipse

optics with clean, dry air prior to calibration initiation

to ensure that an accurate zero (clean air) condition

is present.

The following Normal Calibration guidelines always

apply:

A. The Eclipse is factory set for detection of

methane, propane, ethylene, or butane. If the

gas setting is changed (using HART, MODBUS

or EQP communication), the Eclipse must be

re-calibrated (normally with the matching gas

type).

B. The calibration gas type normally should match

the selected gas setting for the Eclipse. Different

calibration gas types are selectable using HART,

MODBUS or EQP communication.

C. The recommended calibration gas concentration

is 50% LFL, although other calibration

concentrations may be utilized if previously

defined in the Eclipse using HART, MODBUS or

EQP communication.

2. zero only Calibration is a one-step process

consisting of clean air (zero) condition adjustment

only, which is performed automatically by the device.

This procedure adjusts the "clean air" signal output

only, and is normally used if the 4 milliampere signal

level has drifted. The cause of drift is typically due to

the presence of background gas during calibration.

Purge the Eclipse optics with clean, dry compressed

air prior to calibration initiation to ensure an accurate

zero (clean air) condition is present.

aDDitional Calibration noteS

Important

Always ensure that the correct gas type is used for
calibration. (2.5 LPM flow rate is recommended.)

NOTE

It is highly recommended that the detector has
been operating for at least two hours before
calibrating.

NOTE

Always ensure that the Eclipse optics are totally
free of all hydrocarbons before initiating calibration.
This may require purging of the Eclipse with pure
air prior to initiating calibration.

NOTE

Under very windy conditions, it may not be
possible to successfully calibrate the Eclipse. This
situation is easily corrected by using the Eclipse
Calibration Bag (P/N 006682-002), available from
Det-Tronics.

NOTE

Always place the protective cap back on
the calibration nozzle after completion of span
calibration.