EM34 Periodic Daily Checks

It is important to perform EM34 Periodic Daily Checks

to maintain accurate, consistent readings.


Nulling – Daily

Nulling should be performed once a day. This procedure is also described in the EM34 Assembly and Initial Setup page. LINK

1. Set the equipment up at the largest coil separation that will be used on the job site. Disconnect the receiver coil if it is already connected. (Keep the transmitter coil connected to its console.)

2. Turn the power on to the transmitter console and receiver console.

3. Switch the Sensitivity Range to 1000mS/s on the receiver coil. Depress the “NULL” button. Both meter readings should go to zero.

4. If the either meters do not read zero, unlock the appropriate control potentiometer by turning the locknut counter-clockwise. With a screwdriver, adjust the potentiometer until each meter reads zero.

EM34 Periodic Daily Checks

Adjust potentiometers

5. Retighten the locknut. The instrument has now been sufficiently nulled. Reconnect the receiver coil to the receiver coil.


Other EM34 Periodic Daily Checks:

Receiver Battery

1. On the receiver console, switch the Separation to BATT+/-.

2. Turn the receiver console power on. The digital meter should indicate the condition of two sets of batteries. Brand new batteries should have a reading of +/- 6.0 volts. If the reading is below +/-4.5 volts, the user should check the battery connections. Replace the connections if needed. If the connections seem to be in good shape, replace the batteries.

Transmitter Battery

1. With the transmitter coil connected and the level switched to the “High” position, the needle of the transmitter battery meter should be in the black area.

To Change Batteries:

1. Open the console using screwdriver.

EM34 Periodic Daily Checks

Open Console Battery Compartment


2. Check battery contacts. Do battery ends touch contacts? Are the contacts corroded? Are all the wires secured to the contacts? Are all the batteries orientated correctly in the battery compartment? If there are any problems with the battery contacts, notify the rental company. If the battery contacts seem to be in good condition, replace the batteries.

EM34 Periodic Daily Checks

Console Batteries


Transmitter Output Power

Transmitter output power can be set to the “Normal” or “High” position. In most instances, this setting should be “Normal.” Only in environments were the instrument is experiencing a large amount of noise should the transmitter output power be switched to “High” when taking readings.


EM34 Periodic Daily Checks ensure a accurate and successful survey!


Instrument Calibration – For advanced users only

Before leaving the manufacturer, the EM34 should be calibrated to read correctly. In regions of low conductivity and where values are known, it may help to fine tune the instrument. Always take detailed notes before making adjustments to the EM34 calibration in case the settings need to be changed back to their original settings.

1. After deciding what the new reading should be, access the instrument zero control by removing the receiver console chassis from its metal cover by removing the battery lid and two side screws.

2.Adjust the zero control potentiometers as needed. Each coil separation has a potentiometer located on circuit board No. 5: 10m- R15, 20m -R14, 40m-R13. Only adjust the coil separations that will be used in the field.

3. After adjusting the instrument calibration, recheck the instrument nulling. Re-null and repeat zero adjustment as necessary.