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CPT6010 Operating Instructions
Digital Pressure Transducer
CPT6010
7.7 Zero Adjustment
To adjust zero, first determine the correct zero offset, then send the password, and then send the
new zero value. Applying the correct zero pressure and finding the resulting zero offset is different
for an absolute transducer than it is for a gauge type unit. Once the zero offset is known, the proce-
dure for sending the zero correction value (which sets the output to zero) is the same for either type
of transducer. When the zero offset is correct, issue a SAVE command to preserve it in non-volatile
memory.
7.7.1 Gauge/Differential Zero Offset
Substitute the required password in place of “PW” in the following examples:
1. Determine the current zero offset and make a note of the returned reading.
Next send: #*ZC?<cr><lf>
Record the date and this reading to track zero changes between calibrations.
2. Vent the PRESSURE and REFERENCE ports to atmosphere. The true pressure is now 0 (zero).
Send: #*PW<cr><lf>
Next send: #*ZC<sp>0<cr><lf>
This will clear the current zero offset from RAM.
3. While vented, determine the current zero pressure reading of the CPT6010.
Send: #*?<cr><lf>
Make a note of the zero value returned by the CPT6010.
4. Subtract the current zero reading from true zero. The difference is the new zero offset.
Example: For a 0-30 psi unit with both ports vented:
True pressure = 0 (vented)
Current pressure reading (from step 4) = +0.0023 psi
True pressure – current pressure = new offset
0.0000 (–) +0.0023 = –0.0023 psi offset
5. Enter the new offset into memory.
Send: #*PW<cr><lf>
Next send the zero offset: #*ZC<sp>–.0023<cr><lf>
The new offset of –0.0023 will now be added to all pressure readings of the CPT6010.
Send: #*SAVE<cr><lf> to store the new value in non-volatile memory.
6. To check the zero correction:
Send: #*?<cr><lf>
The reading returned should be 0.0000 psi with both ports vented.
7.7.2 Absolute Zero Offset
