4
98MANAL574 Rev. F
NSR EXAMPLE
You have Viatran’s Model 574 with a standard range of 0 to 300 PSI. You would like to set an NSR of 0 to 150 PSI.
Refer to the Performance Certificate and obtain the following:
Zero = 0 PSI = 4.00 Ma
Full Scale = 300 PSI = 20.00 mA
Cal Value = 90.04 PSI = 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 PSI. 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 PSI.
ACCESSORIES - OPTIONAL EQUIPMENT
Polypropylene Conduit Connection Box - NEMA 4X (4 Connection, Dual Terminal Block) .................. 10000PT-25
Polypropylene Conduit Connection Box (10000PT-25) with 8 Ft. Cable ............................................... 003667.003
Mounting Bracket (Process Flanges – 2” Pipe Mount) ..........................……………………………......... 003791.003
Replacement Process Flanges ........................................................................…………………….......... 010454.003
Digital Indicator (Panel Mount) .....................……………………………….....……............................. Consult Factory
Direct Mount Indicator ......................………………………………….....................…......................... Consult Factory
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. The 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 to Viatran for evaluation.
2. 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).
3. 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.
4.
NEVER
- Strike a presumed failed transmitter. If the transmitter is in working order, the shock could cause
additional failure.
NEVER
- Remove a transmitter from an instrumentation loop with the power on. Protection circuitry designed to
absorb small power surges could become shorted and cause transmitter failure due to “arking”.
NEVER
- Ground a transmitter to AC Return (Black). Instant “fatal” failure occurs.
NEVER
- Apply input power to the case ground (Green wire). Reduced life span of protection components will
occur.
MAINTENANCE AND REPAIR
All Viatran transmitters have been designed to function free from routine or scheduled maintenance. Simple cleaning
of the electrical connector, pressure port threads and pressure cavity on an as needed basis will provide many years
of satisfactory performance. Protecting the product from continued exposure to moisture or fluids at the electrical
connection, breather area (model dependent) will eliminate premature internal failure of the product. Generally, any
time the product is removed from service the connector and pressure port threads should be cleaned and the
pressure cavity flushed with a 316 stainless steel compatible cleaner to prevent media buildup.
It is suggested that the calibration be verified on a usage dependent schedule. If the product is in continuous service
7 days a week, then calibration verification may be necessary every 6 to 8 months. If the product is in a lab test
environment a more lenient verification schedule would be appropriate. In all instances the performance of the
product will depend on the individual application or process in which it is installed. More continued usage would
require a shorter period between calibration verification and product maintenance.
If a product is perceived to be exhibiting problems, it can be returned to Viatran for analysis and/or repair. It is
suggested that only Viatran personnel attempt repair of the product. Any damage resulting from customer
disassembly would result in a loss of coverage under the warranty policy. All Viatran products are able to be repaired
