Auto Calibration; Overview - Emerson NGA2000 Instruction Manual

Model NGA2000 I/O Modules

3-1 OVERVIEW

See Section 1 for information that applies to
all I/O Modules. The calibration routine in the
Analyzer Module menu structure is strictly
manual: 1) Open zero/span gas valves manu-
ally, 2) wait for stabilization of displayed val-
ues, 3) initiate calibration routine.
The Auto Calibration I/O Module allows the
user to "manually" or automatically initiate
calibration routines for one Analyzer Module
while solenoids handle gas valve manipula-
tion. The actual calibration routine initiation
can be manual or preset for timing, intervals
and sequencing.
The Auto Cal I/O Module also provides analog
signal output.
Up to four span solenoid valves and one zero
solenoid valve (customer supplied) can be
triggered at set time intervals. The frequency
and duration of the calibration cycle is soft-
ware programmable, allowing many varied
sequences, a few of which follow:
•
zero x times, then span
•
zero, then span
•
zero, check on midpoint, then span
Four SPST and two SPDT relays are used to
drive solenoid valves that control the flow of
zero and span calibration gases to the Ana-
lyzer Module. The seventh relay indicates an
in-calibration condition on the network.
•
Line 1 - do zero calibration
•
Line 2 - do span calibration
•
Line 3 - do a zero and a span as pro-
grammed
•
Lines 4 & 5 - select the desired range in
the following binary fashion (for Line 2
above ONLY):
Rosemount Analytical Inc. A Division of Emerson Process Management
SECTION 3

AUTO CALIBRATION

Instruction Manual
Range Line 4
1 OFF
2 ON
3 OFF
4 ON
•
Line 6 - disables calibration instruction
and allows only a check to occur
Note the following:
These remote functions will apply only if
the remote controls are enabled through
this I/O Module.
Lines 4 and 5 control only the desired
range of the span function as described in
Line 2.
If the digital lines described above are not
connected, the Line 2-related span func-
tion will only select Range 1; it will not
calibrate any other range. However, the
Line 3 function will span or check ranges
as set up in the module's programming.
After calibration, the Analyzer Module will
be returned to the range it was operating
on previous to calibration.
Characterizations for pins 5 through 18 in Fig-
ure 1-5 (relative to SPDT or SPST and NC, C,
NO or C) remain accurate, but pin assign-
ments relative to specific relays are different
for the Auto Cal I/O Module. Those pin as-
signments are as follows:
Pin 5 - Relay 7 Pin 12 - Relay 6
Pin 6 - Relay 7 Pin 13 - Relay 6
Pin 7 - Relay 7 Pin 14 - Relay 3
Pin 8 - Relay 5 Pin 15 - Relay 4
Pin 9 - Relay 5 Pin 16 - Relay 1
Pin 10 - Relay 5 Pin 17 - 1-4 COM
Pin 11 - Relay 6 Pin 18 - Relay 2
After calibration, the output signal is then cor-
rected for zero and span. (See Figure 3-1 for
a flowchart depicting menu screens related to
this I/O Module.)
748275-F
September 2003
Line 5
OFF
OFF
ON
ON
Auto Calibration 3-1