Oldham MX 52, Installation Manual

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Please note: When the value measured is >= 100% LEL, the measuring device memorises the
fact that the value has exceeded the scale and the channels switch to alarm and fault mode.
Resetting these statuses is a manual operation to be performed by the user, who must follow
the safety regulations specific to the site. The reset is checked either by turning the device on
and off or by a maintenance inspection.
5.3.2. Device transfer curves in 0% to 30.0% OXYGEN configuration
The following curve shows the response of the device in terms of value measured, and
fault processing as a function of the input current value supplied by the detector. Where the
user connects a brand of detector other than OLDHAM to the MX52 device, he must check
carefully that the transfer curve is fully compatible with the device input characteristics, to
ensure that the data generated by the detector is correctly interpreted. Equally, the device must
supply a suitable power supply voltage, allowing for cable voltage losses.
5.3.3. Power supply and load resistance characteristics
Maximum current available between terminals 2 and 3: 350 mA at 21 V.
Maximum no-load voltage between terminals 2 and 3: 30 V
Load resistance (outside the IS barrier) between terminals 1 and 2: 47 ohms
N.B.: This data applies only where detectors other than OLDHAM are used. Where
different types are mixed, please contact OLDHAM to establish the feasibility of the
combination.
5.4. MARKING
OLDHAM
0080
II 2 (G)
INERIS 04ATEX0064
4
mA 20
mA
Signal supplied by
the detector in mA
Display in % O2
by volume
Fault
Fault
1.2
mA
0.0 %
-5.3%
30.0%
36.0%
23.2
mA