Series 570LX-701-C1-10 SmartPack User's Manual Dual Process Current Output
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nci_callo[ x ]: Calibration Low Variable
Declaration
eeprom network input SNVT_lev_percent nci_callo[ 2 ];
Description
This configuration input network variable contains the value
corresponding to the nominal 4 mA or 0% output. See the
Calibration section for a complete description of its use. This
variable is maintained in EEPROM and does not take effect
until the module is reset.
Initial Factory Value
0.0% of span (0), or 4.00 mA.
nci_calhi[ x ]: Calibration High Variable
Declaration
eeprom network input SNVT_lev_percent nci_calhi[ 2 ];
Description
This configuration input network variable contains the value
corresponding to the nominal 20 mA or 100% output. See
the Calibration section for a complete description of its use.
This variable is maintained in EEPROM, and does not take
effect until the module is reset.
Initial Factory Value
100.0% of span (20000), or 20.00 mA.
CALIBRATION:
All modules are calibrated at the factory and additional
calibration is not normally required. However, if it does become
necessary to calibrate the module, follow the procedure outlined
below for each output. Values in parenthesis indicate the
SNVT_lev_percent value. See Figure 3 for the relationship
between output current and SNVT_lev_percent value.
Equipment Required
1. DVM capable of accurately measuring 4-20 mA. See drawing
4501-331.
2. Network management tool capable of writing the module's
network variables.
Procedure
1. Write a value of 0% (0) to the nvi_pvin[ x ] variable to cause
the output to go to 4 mA, nominal. Note the actual mA value
measured by the DVM.
2. Write the SNVT_lev_percent value corresponding to the
measured value of the DVM to the nci_callo[ x ] network
variable for the input.
3. Write a value of 100% (20000) to the nvi_pvin[ x ] variable to
cause the output to go to 20 mA nominal. Note the actual
mA value measured by the DVM.
4. Write the SNVT_lev_percent value corresponding to the
measured value of the DVM to the nci_callo[ x ] network
variable for the input.
5. (Optional) Write a new value to the nci_watchdog[ x ]
variable as required.
6. Reset the module. New internal calibration coefficients are
now calculated using the nci_callo[ x ] and nci_calhi[ x ]
values.
7. Write a value of 50% (10000) to the nvi_pvin[ x ] variable to
cause the output to go to 12 mA. The DVM should indicate a
value of 12.00mA
±
0.05% (8 uA) of output span.
Note:
If the output will not calibrate after performing the
above calibration sequence, write a value of 0 into the
nci_calhi[ x ] variable and reset the module. This will cause
the initial factory values to be recalled for all configuration
variables associated with the analog output. Then carefully
repeat the above calibration sequence.
GENERAL MAINTENANCE:
The module contains solid-state components and requires no
maintenance, except for periodic cleaning and calibration
verification. When a failure is suspected, a convenient method
for identifying a faulty module is to exchange it with a known good
unit. It is highly recommended that a non-functioning module be
returned to Acromag for repair, since Acromag makes use of
tested and burned-in parts, and in some cases, parts that have
been selected for characteristics beyond that specified by the
manufacturer. Further, Acromag has automated test equipment
that thoroughly checks the performance of each module.
