Biological Sciences 300/301, Smith College | Neurophysiology

Appendix: Using Gould TA240 EasyGraf Chart Recorders

Gould "EasyGraf" chart recorders

Our Gould TA240 chart recorders use thermal array technology: a fixed writing element composed of many tiny dots heats up a special paper to print the trace, the chart grid, and annotations. The chart recorders can write two channels of extracellular action potentials or other signals directly from the preamplifier. Each channel's vertical sensitivity is set by a combination of a pushbutton switch (x100, x1) and a dial. The dial's units are "volts full scale," which is the total voltage spanned by the entire width of the channel (not the volts per division as on the oscilloscope screen).

The chart speed is controlled by a set of pushbuttons at the top right. If you are not sure what speed to use, 10 mm/sec is a good setting to start with. The last important control is for channel position, just above the exit slot for the paper. The knob on the left controls channel 1, and a green LED array shows you the approximate position of the trace even when the chart is not moving. The knob on the right controls channel 2. Set each channel's baseline position so the displayed signals take up most of the chart. If you are not using a channel, pull out its position knob to turn off that channel's trace.

The time of day and the date are set by buttons in the panel above the chart:

To set the time, press the select (SEL) button repeatedly until the green light next to TIME is on. Press SET to activate time entry (the display will turn blank). Enter the clock time on the keypad, preferably using 24 hour time (eg, 1:15:00 pm is 13 15 00). Press SET again to enter the time. The display will now run as a digital clock showing hours, minutes and seconds.

To set the date, press the select (SEL) button to choose the DATE, and press SET to activate entry. Type the date on the keypad as mm/dd/yy. Press SET again to enter the date.

You do not need to enter an ID number, but you should select TIME again so the display becomes a digital clock.

By pressing the buttons at the right repeatedly, set:

  • GRID to OVLP (overlap), so that both channels share the same grid
  • EVENT to TIMER, which will print a tic mark every second at the edge of the chart
  • ANNOT (annotation) to ON, which will cause the date, time, chart speed, and other useful information to be printed on the chart.

Excerpts from the EasyGraf manual with additional details on these settings are reproduced below.


Excerpts from the EasyGraf Instruction Manual

Diagram of front panel

Start-up procedure

Typical application (includes setting date and time)

Diagram of chart annotations