ETS-Lindgren HI-3627, User Manual

Page: 19 / 39

ets-lindgren.com Operation 19
Figure 4-2: Recorder Output
The connection for the recorder output is made through the same
connector as the battery charger (refer to figure 4-2). This is a two
circuit connector (jack) that mates with a standard ¼ inch stereo phone
plug. The ring of the phone plug is reserved for battery charger input
and the tip is connected to the recorder output. The shaft of the plug is
the common ground. A diode in the battery charging circuit keeps the
battery voltage from being applied to the recorder output when a plug
is inserted into the jack.
The recorder output comes directly from the circuit driving the meter
movement. The maximum current available to the recorder output jack
is 1 milliampere (5000 ohm minimum recorder output load). A lower
impedance recorder output load will affect the accuracy of both the
meter reading and the signal to the recorder output.
The meter movement and the recorder output are driven by a PWM
(pulse width modulator). This leads to a small amount of ripple on the
recorder output, typically 50 mV at 40 Hz.