TS4000
45
5.5 MODBUS Read Status Protocol (Query / Response)
A master device reads registers from the TS4000 by sending an 8-byte message as described
in Table 17.
Table 17: MODBUS Read Register(s) Request
Byte
MODBUS
Range
Referenced to TS4000
1st Slave
Address
1-247
*
(Decimal)
TS4000 ID (Address)
2nd Function Code
03
Read Holding Registers
3rd
Starting Address Hi
00
Not Used by the TS4000
4th
Starting Address Lo
00-44 (Hex)
TS4000 Commands
5th
Number of Registers Hi
00
Not Used by the TS4000
6th
Number of Registers Lo
**
01 – 45 (Hex)
Number of 16 Bit Registers
7th
CRC Lo
00-FF (Hex)
CRC Lo Byte
8th
CRC Hi
00-FF (Hex)
CRC Hi Byte
*
Address 0 is reserved for Broadcast Mode and is not supported at this time.
**
A maximum of 69 registers can be requested during a single block of time.
Upon receiving a valid read register request from the master device, the TS4000 will respond
with a message as described in Table 18. If the query generates an error, an exception
message is returned to the master device (refer to Section 5.7).
Table 18: MODBUS Read Register(s) Response
Byte
MODBUS
Range
Referenced to TS4000
1
st
Slave Address
1-247* (Decimal)
TS4000 ID (Address)
2
nd
Function Code
03
Read Holding Registers
3
rd
Byte Count **
02 – 8A (Hex)
Number of Data Bytes (N
+
)
4
th
Data Hi **
00-FF (Hex)
TS4000 Hi Byte Status Data
5
th
Data Lo **
00-FF (Hex)
TS4000 Lo Byte Status Data
:
:
:
:
:
:
:
:
N
+
+4 CRC Hi
00-FF (Hex)
CRC Hi Byte
N
+
+5 CRC Lo
00-FF (Hex)
CRC Lo Byte
* Address 0 is reserved for Broadcast Mode and is not supported at this time.
** Byte count and the number of returned data bytes depends on the number of requested
registers.
+
N denotes the number of returned data bytes.