7600 Controller - User Manual

Model 7600 Controller Users Manual

Revision B

IMPORTANT! Figure 2.3 CAL MODE menus are only visible if the Input Data From: menu, described in section 2.2.7, is set for Sensor.

Figure 2.3 illustrates how the CAL MODE menus function to allow push button calibration of zero and span values. The correct zero and span set-point values must be entered in order for the to make the correct adjustments. This feature should be utilized only when there are no other zero/span controls within the monitoring system since it is inappropriate to calibrate the same signal at more than one point. Therefore, if calibration is to be performed at another transmitter or monitoring device, the CAL

MODE feature should not be used. Unintentional calibrations are reset by the UNITY

GAIN menu. Unity gain sets zero offset to 0 and span gain to 1.

A/D Cnts = 905

Edit = Cal Mode

Press Edit

0 PCTLEL

Edit = Cal Zero

Press Edit

Reading =Zero

Cal Set-Point

Press Dn

Press Up/Dn

Edit = Unity

Resets Cal Mode

Press Edit

51 PCTLEL

Edit = Cal Span

Press Edit

Offset = 0

Gain = 1

Reading =Span

Cal Set-Point

Press Dn Press Func.

0.000=Cal Zero

50.0=Cal Span

Returns to

Normal Mode*

Figure 2.3

The bottom line of the top left menu in Figure 2.3 allows access to the calibration menus by pressing EDIT. EDIT brings up the CAL ZERO display at the top right of Figure 2.3.

The top line displays the live channel value in engineering units and the bottom line states: EDIT = ZERO CAL. It is important to understand that pressing EDIT now will force this channel’s reading to match the zero set-point value previously entered.

Therefore, the sensor should have the appropriate stimulus to provide a response approximating the zero set-point. Pressing the Up or Down buttons from the CAL ZERO menu brings up the CAL SPAN menu. Pressing EDIT will cause a span adjustment forcing the reading to match the span set-point value previously entered. Again, the sensor should have the appropriate stimulus to provide a response approximating the span set-point. For example, if an LEL combustible sensor is to be spanned with 50% LEL

Scott Safety 6 087-0018 Rev B