KMPS-1-64 Manual
12/18
KM 8000 Rev. A
Page 35 of 40
Copyright © 2018 Kulite Semiconductor Products, Inc.
All Rights Reserved.
APPENDIX C
KMPS-1-64 User Calibration
The user has the ability to adjust to offset and gain for each of the 64 channels on the
KMPS-1-64. To adjust the coefficients the user must enter programming mode using the
MOde command.
The user then must read both the pressure output at both zero and full scale pressure.
Pressure is read using the PRessure command (e.g. $00PE 0 will read the pressure from
channel 0).
The user then must read the user gain and user offset coefficients for the channel of interest
using the OFfset and SLope commands (e.g. $00SL 12 will read the gain coefficient for
channel 12).
Output pressure is calculated using the formula:
𝑃
𝑜𝑢𝑡
= 𝑂
𝑈
+ 𝐺
𝑈
𝐹(𝑇, 𝑃
𝑟𝑎𝑤
) + 𝑂(𝑇)
Where O
U
is the user offset, G
U
is the user gain, and F(T, P
raw
) and O(T) are functions of
temperature and pressure used to correct for thermal and pressure non-linearity errors.
To determine the new fixed gain coefficient the user must use the formula:
𝐺
𝑈
=
∆𝑃
𝑁𝑒𝑤
∆𝑃
𝑂𝑙𝑑
∗ 𝐺
𝑜𝑙𝑑
Where ΔP is the difference between the full scale and the zero reading. As an example if
the user originally measured a full scale of 99 PSI and a zero of 1 PSI with a full scale of
100 PSI and a user gain reading of 1.001 and wanted a new delta of 100 PSI then they
would use:
G
old
= 1.001
ΔP
old
= (99
– 1) = 98
ΔP
new
= 100 = 100
G
u
= 100/98 * 1.001 = 1.02143
To determine the new offset coefficient the user must take another reading at any pressure
with the new gain setting and use the formula:
𝑂
𝑢
= 𝑃
𝑛𝑒𝑤
− 𝑃
𝑜𝑙𝑑
+ 𝑂
𝑜𝑙𝑑
Continuing from the above example if the user measured 0.95 PSIA at 1 PSIA after
adjusting the gain they would use:
P
old
= 0.95
P
new
= 1
O
old
= 0.1
O
new
= 1
– 0.95 + 0.1 = -0.15
If the gain is already correct then it is possible to just adjust only the zero with the above
formula, but any change in gain will affect the offset.
These new coefficients can be uploaded into the onboard module EEPROM using the
SLope and OFfset commands (e.g. SL 0 1.02143) will upload a new gain of 1.02143 for
channel 0). The changes to the values take place immediately. If an incorrect value is
mistakenly entered the default values of 0 for offset and 1 for gain can be entered and then
new values can be calculated from new readings.
Summary of Contents for KMPS-1-64 Series
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