Teledyne Everywhereyoulook MX 62 User Manual page 14

WB Interface
WB/4-20mA CONVERTER
USER MANUAL
5.3.1 Setting the zero
•
Necessary when changing sensor.
•
At least once yearly and according to use.
•
Connect a voltmeter to the two studs provided (MF and MES), as shown in Figure 4.
If in the course of setting, you wish to inhibit the alarms on the central measuring
unit (relay), flick the maintenance switch (of the channel concerned) up (Figure 4,
ref. 1 and ref. 2) which will block the corresponding 4/20 mA output at 2 mA
and the amber "TEST" LED will light up (rep7,Figure 4)
(↑ Up)
Once the settings are complete, remember to put the switch back to the normal
position
• Make sure that the atmosphere is gas free (if this is not the case, air needs to be injected).
• Adjust the ZERO using the ZERO potentiometer: Figure 4, Ref. 3 (channel 1) or Figure 4,
Ref. 4 (channel 2). The voltmeter should read "40 mV".
• N.B. Once set, the corresponding 4 / 20 mA output will deliver 4 mA (maintenance switch
in "normal" position).
5.3.2 Adjusting the gas span
• Necessary when changing sensor.
• At least once yearly and according to use.
• Connect a voltmeter to the two studs provided (MF and MES), as shown in Figure 4.
• Prepare the calibration kit and attach the gas infeed pipe to the sensor.
• Set the calibration gas flow to 60 l/h before injecting.
• Inject the gas: to achieve a correct setting, OLDHAM recommends using a
content at least equal to 30% of the scale (30% LEL of the gas concerned).
• Wait at least 30 seconds for the reading to stabilise.
Adjust the span using the Span potentiometer: Figure 4, Ref. 5 (channel 1)
•
or Figure 4, Ref. 6 (channel 2). The voltmeter should now read "xx mV"
according to the concentration of the injected gas (see example below).
Once set, and with the gas, the corresponding 4 / 20 mA output will deliver xx
mA. (maintenance switch in "normal" position)
REMINDERS:
10
Maintenance
Normal
NPMWBEN
Revision A.0