EV/DV300 Series Power Meter
V:2.0 Revised October 2018
41
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.
Addr
Fun
Data
start reg
hi
Data
start reg
lo
Data #of
regs hi
Data #of
regs lo
CRC16
hi
CRC16
lo
11H
01H
00H
00H
00H
02H
BFH
5BH
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.
Addr
Fun
Byte Count
Data
CRC16
hi
CRC16
lo
11H
01H
01H
02H
D4H
89H
The content of Data byte
Table 4.5 Read status of Relay1 and Relay2
0
0
0
0
0
0
DO2
DO1
0
0
0
0
0
0
1
0
MSB
LSB
(Relay1 = OFF, Relay2=ON)
