WattMaster WHP | Section 4 |
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5.3.9Checking the Local Loop at a WHP Controller
Diagram
Meter Set To Read DC Volts
The indicated readings are typical of a normal operating system. Actual readings may vary slightly due to the number of units installed and other factors. Any significant deviation from these values generally indicates a problem.
These tests assume that a MiniLink is connected and powered up.
Note:Overview
Proper loop voltages are essential for reliable communications. It is normal to see fluctua- tions on an operating communications loop. The average value should be close to the ac- ceptable range described below. Values will vary upon initial powerup for about
Measurements
| TLocal– SHLDLoop | 2.9 - 3.1 Volts DC | AcceptableRange | ||
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| R – SHLD | 1.9 - 2.1 Volts DC |
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| Action |
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| If meter reads betweenCondition2.4 VDC and 2.5 |
| 1) No CommLinkActionII or MiniLink is con- | ||
| VDC |
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| nected and powered up. | |
| The Comm Loop “floats” at 2.4 - 2.5VDC |
| 2) If a CommLink II or MiniLink is con- | ||
| when only controllers are connected to the |
| nected, look for “open” wiring. | ||
| loop. When a MiniLink is connected it will |
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| “bias” each side of the loop to the values |
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| listed above. |
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| If voltages are too high or too low on either |
| One or more devices connected to this loop | ||
| side |
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| have damaged Comm Driver chips. | |
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