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Articles on the Changhui Instrument Network have explained the analog programming for Siemens PCS7, how to set analog alarm values, and how to configure alarm limits on the operator interface. This article mainly introduces the methods and steps for setting analog units in Siemens PCS7. The unit setting for APL is not determined arbitrarily, but is defined according to PA industry standards. It creates a mapping table that associates common units with numerical codes, and we can retrieve these mappings using the APL help documentation. http://yunrun.com.cn/upload/201910/22/201910221333423862.png As shown in the figure above, different values correspond to different units; for example, “1001” corresponds to “℃”, while “1010” corresponds to “m”. The biggest advantage of this approach is that unit values can be modified online at any time, without the need to compile the OS in order to update those settings. Furthermore, it can also prevent garbled text caused by issues with the project’s language settings. Of course, the previous unit setting method is still available. For setting the analog unit in Siemens PCS7, visit yunrun.com.cn/tech/2751.html and http://yunrun.com.cn/upload/201910/22/201910221334226024.png. As shown in the image above, set the value of “Value” to “0”, and then select the appropriate unit from the dropdown menu under “Unit”. Generally, we set the unit of the analog value by adjusting the “Value” setting, with the specific values determined according to the table in the first diagram. Just like the range, the unit setting needs to be configured only once; thereafter it can be passed between functional blocks. For example, if it is necessary to display the unit of the measurement value on the host computer, it is sufficient to connect the output parameter PV_OutUnit of Pcs7 AnIn to the input parameter PV_Unit of MonAnL in order to transfer this value. http://yunrun.com.cn/upload/201910/22/201910221347565776.png As shown in the figure above, set PV_InUnit to 1001, which corresponds to °C; then connect the output parameter PV_OutUnit of AnIn to the input parameter PV_Unit of MonAnL. This will enable the unit conversion to be carried out, and it will be displayed on the operator’s screen. The unit settings can then be seen on the operation panel. The unit values for all related variables have also been configured at the same time! http://yunrun.com.cn/upload/201910/22/201910221347340593.png As shown in the image above, the temperature unit corresponding to it can be displayed on the screen.