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CPT6010 Operating Instructions
Digital Pressure Transducer
CPT6010
7.8 Span Adjustment
The span adjustment procedure is the same for gauge and absolute units. Always make zero cor-
rections before changing the span factor. A scale factor within the range of 0.9 to 1.1 is used as a
multiplier to correct for span shifts.
1. Determine the current span scale factor and record the reading.
Send: #*SC?<cr><lf>
This reading can be used at some later date to detect a span change between calibrations.
2. To clear the current scale factor:
Send: #*PW<cr><lf>
Next send: #*SC<sp>1<cr><lf>
3. Apply a known true pressure equal to the span of the CPT6010. To determine the CPT6010
pressure reading:
Send: #*?<cr><lf> and make a note of this reading.
4. Divide the known true pressure by the CPT6010 pressure reading. The result is the required new
span scale factor.
Example: For a 150 psi unit:
True pressure = 150.003 psi
CPT6010 pressure reading (from step 3) = 149.984 psi
True pressure / CPT6010 pressure = new span scale factor
150.003/149.984 = 1.000127
5. To enter the new span scale factor:
Send: #*PW<cr><lf>
Then send: #*SC<sp>1.000127<cr><lf>
Send: #*SAVE<cr><lf> to store the new value in non-volatile memory.
All future pressure readings returned by this CPT6010 will be multiplied by a scale factor of
1.000127 before they are transmitted over the bus.
6. To check the span reading:
Send: #*?<cr><lf>
The returned pressure value should be 150.003 psi, if the pressure has not changed.
