3200 Series
94 Part No HA028651 Issue 7.0 Apr-09
16.3
Input Calibration
If the calibration is not within the specified accuracy follow the procedures in this section:-
In 3200 series instruments, inputs which can be calibrated are:-
•
mV Input.
This is a linear 80mV range calibrated at two fixed points. This should always be done before calibrating
either thermocouple or resistance thermometer inputs. mA range calibration is included in the mV range.
•
Thermocouple
calibration involves calibrating the temperature offset of the CJC sensor only. Other aspects of
thermocouple calibration are also included in mV calibration.
•
Resistance Thermometer
. This is also carried out at two fixed points - 150
Ω
and 400
Ω
.
16.3.1
To Calibrate mV Input
Calibration can only be carried out in configuration level.
Calibration of the mV range is carried out using a 50 milli-volt source, connected as described in section 16.1.2. mA
calibration is included in this procedure.
For best results 0mV should be calibrated by disconnecting the copper wires from the mV source and short circuiting the
input to the controller
To calibrate the mV Input, select
Conf
Level
as described in section 6.1.3, set the controller input to mV range, then:-
Operation
Do This
Display View
Additional Notes
Select the Calibration
List header
1.
From any display press
as many times
as necessary until the ‘CAL’
page header is
displayed.
Scrolling display ‘
C A L IB R A T IO N L IS T
’
Select the Calibration
Phase
2.
Press
°
to select ‘P H A S E ’
none
p h a s e
Scrolling display ‘
C A L IB R A T IO N p h a s e
’
Set mV source for 0mV
Select the low
calibration point
3.
Press
V
or
W
to choose ‘
0
’
Calibrate the
instrument to the low
calibration point
(0mV)
4.
Press
°
to select ‘G O ’
5.
Press
V
or
W
to choose ‘
YES
’
Scrolling display ‘
C A L IB R A T IO N s ta rt
’
The controller automatically calibrates to the
injected input mV. The display will show
busy
then
pass
,
(if calibration is successful.) or
‘
FAIL
’ if not. Fail may be due to incorrect
input mV
Set mV source for 50mV
Select the high
calibration point
6.
Press
°
to select ‘P H A S E ’
7.
Press
V
or
W
to choose ‘
50
’
8.
Repeat 5 and 6 above to calibrate the high
point
The controller will again automatically calibrate
to the injected input mV.
If it is not successful then ‘
FAIL
’
will be
displayed