Chapter 8 Network variable bindings
Tracer MP580/581 bindings
This section discusses which network variables will be necessary to achieve UUKL time performance requirements. Only “generic” network variables, which are neither Space Comfort Controller (SCC) or Discharge Air Controller (DAC), are necessary. Use of generic variables does not affect either BCU
Receiving data
A network variable input (nvi) receives data from other devices on the LonTalk network. The generic network variable inputs, nviSwitch and nviPercent, that are commonly used in Tracer MP580/581 bindings are shown in Table 29.
Table 29. Tracer MP580/581 generic network variable inputs
Variable name | SNVT | Data type | Description |
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nviSwitch01 … | SNVT_switch | Binary | Bind to these 40 network variable inputs to communi- |
nviSwitch40 |
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| cate binary values to the device. |
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nviPercent01 … | SNVT_lev_percent | Analog | Bind to these 20 network variable inputs to communi- |
nviPercent20 |
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| cate levels in percent to the device. The valid range is |
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| from |
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Sending data
A network variable output (nvo) sends data to other devices on the Lon- Talk network. The generic network variable outputs, nvoSwitch and nvo- Percent, that are commonly used in Tracer MP580/581 bindings are shown in Table 30.
Table 30. Tracer MP580/581 generic network variable outputs
Variable name | SNVT | Data type | Description |
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nvoSwitch01 … | SNVT_switch | Binary | These 40 network variable outputs communicate binary |
nvoSwitch40 |
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| values to other devices. |
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nvoPercent01 … | SNVT_lev_percent | Analog | These 20 network variable outputs communicate levels |
nvoPercent20 |
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| in percent to other devices. The valid range is from – |
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| 163.84% to 163.83% with a resolution of 0.005%. |
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Heartbeated network variables
All necessary information can be sent using nvoSwitch (SNVT_switch) and nvoPercent (SNVT_lev_percent), which are “heartbeated” variables. All necessary information can be received using nviSwitch (SNVT_switch) and nviPercent (SNVT_lev_percent). Heartbeated variables are a means of indicating freshness of information and/or quality of the communication link. For more information regarding heartbeating, see “Understanding bindings” on page 130.
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