PT200MI instruction manual 18
6.2.2 CALIBRATION 2 (accuracy ~1% by mV/V data input)
Entering the calibration mode:
Press and hold the MODE key, then press the TARE key, 2 seconds later, “CAL 1” displays. Press the
TARE key again and “CAL 2” is displayed. Press the ZERO key, the ZERO annunciator flashes and the
zero calibration stage has been entered. Nothing will show on the display, the G/N or MODE key should
be pressed to continue.
1. ZERO CALIBRATION
If the current zero setting is acceptable it is not necessary to calibrate the zero offset, press the G/N
key to skip the zero calibration procedure, and enter the span calibration stage.
If a new zero offset is to be calibrated press the MODE key to accept the current load as the new 0.
2. SPAN CALIBRATION
Once zero calibration is complete the span calibration stage is reached and the GROSS annunciator
flashes throughout the mV/V entry stage. The indicator will display a value in the format "1.0000",
input the value by selecting the digit to change with the ZERO key and changing the value with the
TARE key. Units are mV/V with 4 decimal places. The “GROSS” annunciator will flash throughout
this stage. Press the G/N key to move to the next stage or the MODE key to accept the entered data
and return to normal weighing. The mV/V value to enter is the amount the signal will change for the
next entered load value. The load value cannot be larger than the scale capacity set in the function
settings.
When G/N is pressed the Gross annunciator is steadily lit. The value shown should be changed by
selecting the digit to change with the ZERO key and changing the value with the TARE key. The
value is the load that would be required to produce the mV/V change previously entered. This value
is entered as digits without decimal point and must be a multiple of the indicator step. If the PT200MI
capacity is set to a capacity 100.00 and the previously entered mV/V was for a load of 50.00 then
enter 5000 at this stage. Press the MODE key to complete and return to normal weighing.
Example: 4 load cells 30 t capacity and nominally 2 mV/V are connected in a scale. Set for 100.00 t
capacity. Obtaining the exact calibration value from the certificates and averaging these yields a
value of 1.9998 mV/V. The scale capacity is 120 t. 120 t is greater than the maximum capacity (100
t) set in the PT200MI so divide the values in half.
Enter 0.9999 for the value of mV/V and press G/N then enter 6000 then press MODE.
6.3 ERROR CODES DURING CALIBRATION
ERROR 1 : Incorrect setting for multiplier, division, or maximum capacity.
ERROR 2 : Incorrect wiring between load cell and indicator, voltage for zero value is greater than the
voltage for span value.
ERROR 3 : Input voltage too low. The dead weight of the weighing platform may be too light. Add a 1%
metal film resistor of 50KΩ to 500KΩbetween EX+ and SG+.
ERROR 4 : Input voltage too high. The dead weight of the weighing platform may be too heavy. Add a
1% metal film resistor of 50KΩ to 500KΩ between EX + and SG-.
ERROR 5 : Input sensitivity of the load cell is out of range.
ERROR 6 : Load cell output voltage at scale capacity is too high.
ERROR 7 : Zero offset is greater than zero return range.
6.4 CALIBRATION USING RS232/RS485 (only if RS232 or RS485 option is installed)
Calibration setting can be conveniently performed by using RS232/RS485 during normal weighing
mode. Refer to the section on RS232/RS485 for connection diagrams.
From the RS232 port, input a command “CAL<CR><LF>”, “CAL 1<CR><LF>” or “CAL2<CR><LF>”, the
display will show “CAL 1” or “CAL 2” throughout the calibration setting mode.
From the RS485 port, input a command “<ENQ>IDXX<CR><LF>”, indicator responds
“<ACK>XX<CR><LF>”, then input a command “CAL<CR><LF>”, “CAL 1<CR><LF>” or
“CAL2<CR><LF>”, the display will show “CAL 1” or “CAL 2”. XX is the indicator ID set in function F14
above.
The sequence of calibration setting via serial port involves sending a series of parameters followed by
<CR><LF> and receiving a subsequent response from the PT200MI. If an invalid parameter is sent
the PT200MI responds NO? <CR><LF> and a correct entry must be made. When the correct
parameter has been sent the PT200MI moves to the next stage.
Note that commands are case sensitive.
Note that INPUT1 must be connected to COM to enter the calibration setting mode unless this setting
is altered in the function setting section. The factory setting for INPUT1 is FUNC.
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