PCC-IV Instruction Manual (rev. 0.1)
Page 4-12
Section 4
–
Menu Operations
Factory calibration data is corrupted: While unlikely, it is possible to corrupt the Blockware or Calibration data. If the
calibration data does not pass the validation tests performed at start-up, the PCC-IV will use default calibration data
and continue operating with the reduced accuracy as described above.
Analog Input Calibration Procedure
WARNING
The PCC-IV is commonly used to control potentially dangerous combustion and chemical
processes. VERIFY THAT THE PROCESS BEING CONTROLLED HAS BEEN SAFELY
SECURED, ISOLATED, OR BYPASSED (AS REQUIRED BY THE SITE CONDITIONS)
BEFORE CALIBRATING THE PCC-IV.
FAILURE TO DO SO CAN RESULT IN EQUIPMENT
DAMAGE, INJURY, OR DEATH.
This procedure requires a low noise voltage source that can produce 2.500 Vdc and 5.000 Vdc, and a DC Voltmeter
to measure the calibration voltages to /- 0.4 mV. This means that the DC
Voltmeter must display at least “5
½ digits” (i.e., 19.9999). However, not all 5 ½ digit Voltmeters have +/- 0.4 mV accuracy, depending on the accuracy
specification of the meter, a 6 ½ digit meter may be required.
Most portable test meters and voltage
calibrators have 4 ½ digits or less of display resolution. “Calibrating” the
PCC-IV with a less than 5 ½ digit DC Voltmeter will result in lower PCC-IV accuracy.
This procedure applies to the CPU Board (Board 0), Option Board 1, and Option Board 2.
1. Set All Outputs to SM, using the Service Manual submenu.
2. Remove all field wiring from all the Analog Input channels on the Board to be calibrated.
Alternatively, un-plug the field wiring connector, and plug-in a spare field wiring connector.
3. Wire all
the “+” terminals of all the channels together, to the Voltage Source, and to the Voltmeter
(see Section 2 for terminal numbers).
4. Wire all
the “-” terminals of all the channels together, to the Voltage Source, and to the Voltmeter.
5. Disconnect all 250 ohm resistors (i.e., switch OFF or remove the jumpers).
6. Go to the Calibrate I/O submenu.
7. Select which Board is being calibrated (CPU Board = 0; Option Card 1 = 1; Option Card 2 = 2).
8. Set Type to AIN.
9. Press Enter.
a. The message
“APPLY 2.500 VOLTS SIGNAL TO CHANNELS 1 – x, THEN PRESS
ENTER” will be displayed.
b.
The error message “MUST BE IN S/M TO CALIBRATE” will be displayed if ALL the
Outputs are NOT in S/M mode.
10. Set the Voltage Source to 2.5000 Vdc, +/-0.0005 Vdc.
11. Press Enter.
a.
The error message “CALIBRATION ABORTED, CHANNEL x OUT OF RANGE +/- yyyy”
will be displayed if:
i. The Voltage Source is not at the correct voltage
ii. A 250-ohm resistor is connected to the input
iii. The Voltage Source is noisy
iv. The A/D has out of tolerance parts
b.
“yyyy” indicates the magnitude of the error, and is used by factory technicians for
diagnostics, values can be 6000 and higher.
c.
If there was an error, press Escape to return to the menu; the original calibration will still
be in effect.
d. If the 2.5 V calibration was successful, the message
“APPLY 5.000 VOLTS SIGNAL TO
CHANNELS 1
– x, THEN PRESS ENTER” will be displayed.
12. Set the Voltage Source to 5.0000 Vdc, +/-0.0005 Vdc.
13. Press Enter.
a. The error message
“CALIBRATION ABORTED, CHANNEL x OUT OF RANGE +/- yyyy”
will be displayed for one of the same reasons described above.
b. If there was an error, press Escape to return to the menu; the original calibration will still
be in effect.
c.
If the 5.0 V calibration was successful, t
he message “Input calibration is complete” will
be displayed.
