Oldham WX16, Руководство пользователя

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WX16 User Manual | 19
The CALIBRATION MENU allows entering the correct Cal ZERO & Cal SPAN set-
point values needed to calibrate the sensor. These are entered in the same
engineering units as input range.
Set Zero & Set Span controls in this menu allow
pushbutton calibration by moving the pointer to each and pressing the EDIT key. A live
reading of the channel’s value allows calibration checks to see if an adjustment is
needed. Unintentional calibrations are reset by the
Unity Gain menu item. Unity Gain
resets zero offset to 0 and span gain to 1. It is useful for returning the calibration to a
known starting place. Sensor aging may be monitored by recording zero and span
readings at
Unity Gain when it is new, and again at later dates when degradation may
have occurred.
To check zero calibration, apply the ZERO calibration value to the sensor and observe
the live reading. If the zero reading differs from the zero setpoint, a calibration is
needed. To calibrate zero, move the pointer to
Set Zero and press EDIT . A warning
message explains that pressing EDIT again will change the zero calibration and any
other key will exit. The procedure for span calibration is identical. For example, if an
LEL combustible sensor is to be spanned with 50% LEL span gas, the span set-point
must be 50%. If 45% LEL is to be used later, the span set-point must be changed to
45% to match the span calibration gas. If the reading is only 40% LEL with the 50%
gas applied a span calibration is needed. Move the pointer to the
Set Span entry and
press EDIT twice. Unity Gain may be used at any time to cancel incorrect calibrations
and start again.
Figure 2.9