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values can be used to determine the expected analog output values (actual values may
vary within the calibration accuracy of the analog output channel, usually within 0.1%FS).
•
Consider a sensor with a 2000 Nm full scale torque measuring range.
•
Calibration values most likely to have been used will be (approximately):- 2000, 0 and
+2000 Nm.
•
The actual values used may have been adjusted to take account of local gravity and
buoyancy and can be seen from the parameters #CALVALUE1, 2 and 3.
•
Make a note of the actual values used and compare them to the values of
#CALCNTS1, 2 and 3.
•
The #CALCNTSx values store the digital counts values that were output by the rotor
for the load conditions given by the relevant #CALVALUEx.
•
The analog voltage output channel is 16-bit and it will generate an output of -12.5V
when it is driven by a counts value of 0, and will generate an output of +12.5V when
driven by a COUNTS value of 65535. Therefore each count generates 0.0003815V
starting from a base of -12.5V.
•
The analog voltage output will be generated in direct relationship to the statement
above. Therefore, using the following data, the analog voltage output will be
#CALVALUE1= -1998.699
•
Therefore at a load of -1998.699 Nm, the analog Voltage will be
(21553*0.0003815) -12.5V = -4.278V
#CALVALUE2=0.000000
•
Therefore at a load of 0 Nm, the analog Voltage will be
(32700*0.0003815) -12.5V = -0.026V
#CALVALUE3=1998.500
•
Therefore at a load of +1998.500 Nm, the analog Voltage will be
(43842*0.0003815)-12.5V = +4.224V
Example 2 - Using the SHUNT CAL Feature
The SHUNT CAL feature operates by switching-in a high precision shunt resistor across one
of the arms of the strain gage bride on the rotor. The change in output that occurs due to this
shunting is repeatable and is often used as a means of calibration. During factory calibration,
the apparent change in torque output due to SHUNT CAL will have been recorded, and this
value can be used to re-calibrate the analog voltage output when in FASTMODE.
•
Consider a sensor with a 2250 Lbf.in measuring range. The factory calibration
certificate will include the changes due to SHUNT CAL as a list of effects such as
follows:
Shunt Calibration
Gross
Zero
Shunt Cal
Nett
%
Note: Hz (10) denotes 10 kHz range (10 kHz +/- 5 kHz), Hz (60) denotes 60 kHz range (60 kHz +/- 20 kHz)
Rev B
April 2012
© 2012 – Honeywell International Inc. All rights reserved
#CALCNTS1= 21553.
#CALCNTS2=32700.
#CALCNTS3=43842
Lbf.in
V
mA
1692.2
7.553
18.025
0
0.031
12.008
1692.2
7.522
6.017
75.21%
75.24%
75.21%
TMS 9250 Product User Manual
2. Modes of Operation
at Analog Output Settings
Hz (10)
Hz (60)
High
13761
75043
10000
60000
2250
3761
15043
75.22%
75.22%
008-0738-00
Low
Units
-2250
Lbf.in
29
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