A.4 | Setting Range Values (Local Zero and Span), Continued | |||||||||
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Procedure, continued |
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| Table |
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| Setting Range Values Using Local Zero and Span | ||||||
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| Adjustments, Continued |
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| Step |
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| Action |
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| 4 | Turn ON transmitter power and let it warm up for a few minutes. |
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| Using an accurate pressure source, apply desired zero equivalent |
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| pressure to transmitter. |
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| ATTENTION | For differential pressure transmitters, apply pressure |
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| to the high pressure head for positive range values or vent both |
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| heads to atmosphere for zero. If zero is to equal a negative value, |
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| apply the equivalent pressure to the low pressure head. For |
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| example, if zero is to equal |
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| the low pressure head and vent the high pressure head for the zero |
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| adjustment. |
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| 5 | Check that milliammeter reading is 4 mA. |
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| If reading … | Then… |
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| is less or greater than 4 mA | go to Step 6. |
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| is correct |
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| ATTENTION | If you have the smart meter with local zero and |
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| span adjustment option, you may substitute the smart meter |
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| readings for the milliammeter readings. For example, with zero input |
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| pressure applied assume that the meter reads 4 inH2O instead of 0 |
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| inH2O. In this case, the meter reading is greater than 0 (or 4 mA). |
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| 6 | a. Press and hold ZERO button on local zero and span assembly or |
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| smart meter. |
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| ATTENTION | The smart meter readings revert to the default unit of |
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| percent (%) during this operation. If the error code Er0 appears on |
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| the display, you are working with a model STD110 transmitter that |
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| does not support the local zero and span adjustments. |
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| b. Press Decrease button once to complete this function. |
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| ATTENTION | The smart meter display goes blank for a 1/2 |
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| second and then returns reading 0%. |
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| c. Check that milliammeter reading equals 4 mA and release ZERO |
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| button. |
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| ATTENTION | If milliammeter reading doesn’t change, be sure you |
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| are not working with a model STD110 transmitter that ignores local |
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| adjustments. The smart meter readings return to the set engineering |
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| units after you release the ZERO button. |
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| Continued on next page | ||
56 | ST 3000 Release 300 Installation Guide | 2/05 |