Differences

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--- spark_counter [2016/09/30 17:29] – update links kingkevin
+++ spark_counter [2016/10/01 10:01] – [peacefair PZEM-004] connector kingkevin
@@ Line 37: / Line 37: @@
 {{:spark_counter:dsc02328.jpg?0x200|PZEM-004 opto-couplers}}
-The meter also provides a UART port to query the measured values.
+The meter also provides a UART port (using an XH-4P connector) to query the measured values.
 Two opto-couplers isolate the main power meter circuits from the TX and RX UART ports.
@@ Line 52: / Line 52: @@
 The {{:spark_counter:pzem-004.rtf|manual}} provides the corresponding commands, but lacks some information.
 The UART configurations is 9600 bps 8N1.
-Before querying the measurements, you have to set an address to the device.
+All commands include a device address (i.e. C0 A8 01 01 = 192.168.1.1).
-Else it won't reply to the other commands.
+Only the device with the specified address will respond.
-The manual uses an IP as address (192.168.1.1 = C0 A8 01 01).
+This allows to query multiple devices on the same UART port, one after another, when they have different addresses.
-No idea why you would set an IP for a UART address.
+Thus you have to set the device's address at least once using the 0xA4 command before querying measurements.
+This address will be saved so the next time (even after power down) you can directly query measurements using the address(se) set in the device(s).
 The commands use the following 7 bytes message format: