EV/DV300 Series Power Meter
V:2.0 Revised October 2018
1. Read Status of Relay (function code 01)
Query
Query message is sent from master to slave device. This function code is used to read status
of Relay Output in slave device. (1=ON,0=OFF), There are 2 relays in the meter. The address
of each relay is Relay1=0000H and Relay2=0001H.
Table 4.4 Example of read RO status from slave No.17.
Response
Response frame message is from slave to master device. The frame includes address, function
code, quantity of data byte, the data and CRC error checking. The data byte contains the
information of status of 2 Relays. The last 2 bits tells the status of Relays. Relay 1 status relates
to LSB and Relay 2 to next left bit of LSB. (status Off=0 and on=1)
Table 4.5 Example response of reading status of Relays.
The content of Data byte
Table 4.5 Read status of Relay1 and Relay2
(Relay1 = OFF, Relay2=ON)