EXCEL 50/100/500/600/800 | ATTRIBUTES |
Broadcast Hysteresis
Broadcast hysteresis (V1.5.x) The attribute "Broadcast Hysteresis" is available for the datapoint type "Global Analog". The attribute "Broadcast Hysteresis" prevents new values from being broadcast to other controllers unless the datapoint value changes (positively or negatively) at least by the amount specified in the attribute "Broadcast Hysteresis". The minimum hysteresis value is
This value can be edited from an operator interface (XI581 [not with XCL5010, Excel 100C], XI582,
Intrinsic Hysteresis for Analog Input Signals
A minimum default hysteresis of 37 mV (24 - 1 bit) for 0 to 10 V input signals is implemented. Due to the nonlinearity of NTC sensors, the hysteresis varies over the temperature range, whereas it is approximately constant for PT 100/1000/3000 and Balco 500 sensors. Approximations of hysteresis depending on the sensor and temperature range are summarized below.
NOTE The Intrinsic Hysteresis for analog input signals is not a user- programmable attribute, but rather an intrinsic hysteresis of the Excel 50/100/500/600/800.
NTC 20k Ω Hysteresis varies nonlinearly over the entire temperature range and depending on whether the upper boundary (MAX LIMIT) or the lower boundary (MIN LIMIT) is exceeded. The approximations shown in Table 8 can be used in practice (intermediate values can be interpolated):
| Table 8. Intrinsic hysteresis values for various temperature ranges | ||||
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| temperature range | average hysteresis | average hysteresis | ||
| MIN LIMIT | MAX LIMIT | |||
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| 2.2 | K (4.0 °F) | 2.5 | K (4.5 °F) | |
| 1.3 | K (2.3 °F) | 1.3 | K (2.3 °F) | |
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| 0 °C (32 °F) | 0.4 | K (0.7 °F) | 0.4 | K (0.7 °F) |
| 40 °C(104 °F) | 0.5 | K (0.9 °F) | 0.4 | K (0.7 °F) |
| 80 °C (40 °F) | 1.5 | K (2.7 °F) | 1.5 | K (2.7 °F) |
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| 100 °C (212 °F) | 3.0 | K (5.4 °F) | 2.7 | K (4.9 °F) |
| 130 °C (266 °F) | 8.5 | K (15.3 °F) | 7.2 | K (13.0 °F) |
PT 100 (not with Excel 100C) | Hysteresis increases approx. linearly with temperature. |
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| Average hysteresis: | 0.75 K (1.35 °F) |
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| Hyst. At | 0.7 K (1.3 °F) |
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| Hyst. At 145 °C (293 °F): | 0.8 K (1.4 °F) |
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PT 1000/1 | Hysteresis increases approx. linearly with temperature. |
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| Average hysteresis: | 0.8 K (1.4 °F) |
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| Hyst. At | 0.7 K (1.3 °F) |
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| Hyst. At 145 °C (293 °F): | 0.9 K (1.6 °F) |
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