McQuay Micro Tech Open Protocol Driver Manual | Page 11 of 35 |
4.4.5.Map Descriptor Example 2 – Read a particular Data Field.
This example illustrates how to read data for one particular field of interest. The data is read every 2.0 seconds and the value obtained is stored in the Data Array named DA_OPERATIONAL_MODES at location 10.
Map_Descriptor_Name | ,Data_Array_Name | ,Data_Array_Offset | ,Function | ,Scan_Interval | ,Node_Name | ,Length | ,Field_Name |
Chiller10_Op_Mode | ,DA_OPERATIONAL_MODES | ,10 | ,Rdbc | ,0s | ,Chiller10 | ,1 | ,Chiller Operation Mode |
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Ensure that you spell and space the field name exactly as it is printed in table Appendix A.2
This Map Descriptor reads one single value from the McQuay device.
4.4.6.Map Descriptor Example 3 – Write.
This example illustrates how to write data to control fields in the McQuay device. This example illustrates the use of the Wrbx (write on change) function. A write message will be generated each time the data at index 0 in the Data Array changes. When writing multibyte fields, several messages are required to transfer the byte values to the McQuay devices. Note that ‘Device_Scaling’ has no meaning when writing to a McQuay device. The user must ensure that valid numbers are written to the data fields.
Map_Descriptor_Name | ,Data_Array_Name | ,Data_Array_Offset | ,Function | ,Node_Name | ,Length | ,Field_Name |
Chiller1_Op_Mode | ,DA_MODES | ,0 | ,Wrbx | ,Chiller1 | ,1 | ,Chiller Operation Mode |
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The data is only written when the contents of element zero of the array named DA_MODES changes.
The name of the data field to be written to.
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