TS4000H
48
5.5 Modbus Read Status Protocol (Query / Response)
A master device reads registers from the TS4000H by sending an 8-byte message as
described in Table 18.
Byte
Modbus
Range
Referenced to TS4000H
1st Slave
Address
1-247
*
(Decimal)
TS4000H ID (Address)
2nd Function Code
03
Read Holding Registers
3rd
Starting Address Hi
00
Not Used by the TS4000H
4th
Starting Address Lo
00-44 (Hex)
TS4000H Commands
5th
Number of Registers Hi
00
Not Used by the TS4000H
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.
Table 18: Modbus Read Register(s) Request
Upon receiving a valid read register request from the master device, the TS4000H will respond
with a message as described in Table 19. If the query generates an error, an exception
message is returned to the master device (refer to Section 5.7).
Byte
Modbus
Range
Referenced to TS4000H
1
st
Slave Address
1-247* (Decimal)
TS4000H 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)
TS4000H Hi Byte Status Data
5
th
Data Lo **
00-FF (Hex)
TS4000H 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.
Table 19: Modbus Read Register(s) Response
