Amprobe CT238A ACDC-Current-Probe - Manual (Page 9)

3
Operating Instructions
Refer to Fig. 1.
Switch On
When the probe is switched on the red LED will illuminate. The LED starts
flashing when the battery voltage is too low for normal operation and warns
the user that it requires changing. This procedure is described in Battery
Replacement.
Zero Adjustment
The output zero offset voltage of the probe may change due to thermal shifts
and other environmental conditions. To adjust the output voltage to zero
depress the thumbwheel and rotate. Ensure that the probe is away from the
current carrying conductor when the adjustment is made.
Current Measurement
Switch on the probe using the On - Off switch and check that the LED is lit.
Connect the output lead to a multimeter.
If necessary adjust the probe output voltage to zero as described in section Zero
Adjustment.
Clamp the jaws of the probe round the conductor ensuring a good contact
between the closing faces of the jaws.
Observe and take measurements as required. Positive output indicates that the
current flow is in the direction shown by the arrow on the probe.
True r.m.s. readings may be obtained by using an appropriate true r.m.s.
multimeter.
Safety
This instrument is designed to be safe under the following conditions:
Use of the probe on uninsulated conductors is limited to 300V r.m.s or d.c. and
frequencies below 1kHz.
Safety in its use is the responsibility of the operator who must be a suitably
qualified or authorized person.
Do not use the probe if any part of the probe including the lead and connector(s)
appear to be damaged or if a malfunction of the instrument is suspected.
When using the probe ensure that your fingers are behind the protective barrier
see Fig. 1
Clean the case periodically by wiping it with a damp cloth and detergent. Do not
use abrasive cleaners or solvents. Do not immerse the probe in liquids.
Battery Replacement
� Warning
Before removing the battery cover, make sure that the probe is remote from any
live electrical circuit.
The red LED will flash when the minimum operating voltage is approached.
Refer to Fig.1 and use the following procedure.
1.
Unclamp the probe from the conductor, turn it off using the On - Off
switch and disconnect the output leads from external equipment.
2. Loosen the captive screw which secures the battery cover.
3. Lift the cover through 30° and pull it clear of the probe body as shown in
Fig 1. The battery is then accessible.
4. Replace the battery and re-fit the battery cover and fasten the screw.
5. Replacement with other than the specified type of battery will invalidate
the warranty. Fit only Type 9 V PP3, Alkaline (MN 1604).
Frequency Response and Accuracy Curves
Refer to Fig. 2.