When pressed the ‘On/Off’ button switches the unit on or off
Getting Started
Begin by inserting the batteries. Remove the back cover and place the 4 supplied
rechargeable batteries in with the poles facing as indicated inside the unit. To give
maximum length of service the batteries should be charged for 24-48 hours. The
batteries charge slowly to give maximum lifetime and charge. Plug the AC adapter
into the HM21 and connect the lead to the mains. A green light on the adapter
indicates that the power is on.
When fully charged the unit can be in used heavily for up to 14 days or lightly used
for up to several months. If the highest currents are used the charge lifetime may be
reduced slightly.
When the battery power is running low the unit will display ‘Battery Low’. The
warning will first be noted at the higher current levels or when changing from
Reverse to Standby.
The unit can be operated via the adapter whether the batteries are inserted or not.
The batteries will charge when the adapter is in use whether the unit is switched on
or not.
First operation of the HM21.
Switch the unit on using the On/Off button. The unit will self calibrate and then
display “Jandel HM21” along with the version number (currently 1.2). It will
indicate that the unit is in Standby and will show ‘H’ indicating ‘high’ resolution.
Plug in the 100 ohm test resistor so that the unit will believe it is measuring a
sample.
Pressing ‘Inc’ or ‘Dec’ will increase / decrease the current. Use these buttons to set
the unit at 1mA.
Press ‘FWD’. The unit is now passing a current through the resistor and measuring
the voltage. As V=IR you can expect a reading of 100mV. The unit’s accuracy is
quoted at 0.5% so the reading should be between 99.50mV and 100.50mV. In
