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98MANAL359 Rev. F 3/21/17
NON-STANDARD RANGE (NSR) CALIBRATION
Definition
NSR: A non-standard range is a customer request to provide alternate scaled readings. Through the use of a single transmitter, numerous
pressure ranges can be monitored. Depending upon the model, the transmitter can be scaled down to any pressure range, from three times to
five times the original range. Only NSR requests for ranges less than the sensor rated range are recommended and in most cases possible.
The module type products have the ability to be re-ranged for different levels of measure. The NSR is possible due to the ability of the
adjustment screws to alter where the zero and span will fall. Refer to the below example for field NSR calibration.
NSR EXAMPLE
You have Viatran’s Model 359 with a standard range of 0 to 300” WCG. You would like to set an NSR of 0 to 150” WCG. Refer to the
Performance Certificate and obtain the following:
Zero = 0” WCG = 4.00 mA
Full Scale = 300” WCG = 20.00 mA
Cal Value = 90.04” WCG = 8.81 mA
In order to recalibrate the transmitter, you must determine the cal reading in mA’s at the NSR range. This is done by calculating what the cal
output should be at the NSR range. For the example listed, the standard calibration value is set to represent 90.04“ WCG. Once internally set,
the calibration (Cal) will always represent this pressure.
Use the formula: Cal mA’s = [(16 x Standard Cal Pressure) / desired range] + 4
Substitute Actual Numbers: Cal mA’s = [(16 x 90.04) / 150] + 4
Cal mA’s = (1440.64 / 150) + 4
Cal mA’s = 9.604 + 4
Cal mA’s = 13.604 mA’s
The zero would be set for 4.00 mA’s, and the calibration circuit will read (after adjusting span) 13.604 mA’s when activated. This would provide
a new NSR range for the unit of 4-20 mA’s over 0-150“ WCG.
ACCESSORIES - OPTIONAL EQUIPMENT
Please contact Viatran for these and other available accessories.
O-Rings
Retaining Nut (Required for all
adapters)
Retaining Nut Wrench
Polyhead Connection Box
Digital Indicators
Tank Adapters
Tank Shell (Receiver)
Tank Shell Bezel
Tank Plugs
PREVENTATIVE MAINTENANCE
Note: This checklist should be followed each time a transmitter requires preventative maintenance. Depending on product usage cycle, all
maintenance should be done on a schedule that is reflective of the application.
1.
Cleaning in place is the recommended process that should be performed as the system or process permits.
2.
The O-Ring seal and sensor surface should be visually checked whenever the unit is removed or every 6 months, usage dependent. Any
visible damage, especially deep gouges or cuts in the sensor, would require the unit to be returned for evaluation. A soft, lint-free, cloth
dampened with a process recommended cleaner may be used to clean the sensor to remove excessive media buildup. Never use
compounds or solvents that are not compatible with the wetted materials. The sensor area should never be scrubbed with a stiff or metal
brush.
3.
The sensor surface and/or gasket seal should be visually checked whenever the unit is removed or every 6 months (usage dependent). Any
visible damage, especially deep gouges or cuts in the sensor, would require the unit to be returned to Viatran for evaluation.
4.
Care should be used when handling the unit by the connection wires. Continued movement of these wires will weaken the seal. Seal failure
will result in internal contamination and non-warranty product failure. Visually inspect the connection area every 6 months (usage dependent).
5.
The module door should always remain (closed) over the adjustment screws. Constant exposure of the adjustment screws to mists, dusts or
contaminants could cause them to become “frozen” in place, causing the module to become locked and non-usable. This would render
external adjustment difficult at best. Replacement magnets are available if this problem occurs. Hence a visual inspection of the calibration
pots should take place on a 2 to 4 week schedule, or when extreme environmental conditions require it.
6.
NEVER - Strike a presumed failed transmitter. If the transmitter is in working order, the shock could (and usually does) cause additional
failure.
