`
- 40 -
Data field byte length; read data L≤200, write data≤50, L =0 means there is no data field
e)
Error calibration CS
The sum of modulus 256 of all bytes starting from the frame begin symbol to calibration code,
namely
binary arithmetic sum of all bytes is no more than 256 overflow value.
f)
symbol
16H
Indicate the end of one frame of data
9.3.2
Transmission
a)
Lead byte
Before sending frame information, transmit 1
～
4 bytes FEH to awaken the receiver .
b)
Transmission sequence
All data will have the low bytes sent before the high bytes. All data transmitted (except for switch
volume) are the compressed BCD code of actual data plus 33H, e.g. external host reading
ACR220ELH/ACR320ELH forward active electric energy meter address 1:
Host sending
：FE FE 68 01 00 00 00 00 00 68 01 02 43 C3 DA 16
ACR220ELH/ACR320ELH
response
（0.40kWh）：68 01 00 00 00 00 00 68 81 06 43 C3 73 33 33 33 6A 16
c)
Transmission response
Each communication starts when the host station sends request command frame to the slave station
determined according to the information frame address field and the requested slave station makes
response according to the control code of the command frame.
Response delay after receiving order frame
：
≤500ms
Byte calibration is the even calibration while the frame calibration means longitudinal information
calibration sum; in case of detecting even calibration or longitudinal information calibration and error, the
receiver will reject the corresponding information frame without making response.
d)
Error control
Byte calibration is the even calibration while the frame calibration means longitudinal information calibration
sum; in case of detecting even calibration or longitudinal information calibration and error, the receiver will
reject the corresponding information frame without making response.
e)
Transmission speed
Initial speed: 9600bps
Set as: 1200, 2400, 4800, 9600, 19200bps
Data label table
Table 1
S/N Variables
Send example (take broadcast address as an
example, the user may conduct setting
according to actual demand, address high bit
filled by "00000000")
Return
bytes
Return data
format
(secondary
side)
返回数据
单位
1
Forward active
electric energy
68 99 99 99 99 99 99 68 01 02 43 C3 6F 16
4
XXXXXX．XX
kWh
2
Backward active
electric energy
68 99 99 99 99 99 99 68 01 02 53 C3 7F 16
4
XXXXXX．XX
kWh
3
Forward passive
68 99 99 99 99 99 99 68 01 02 43 C4 70 16
4
XXXXXX．XX
kvarh