GE AquaTrans AT600 - Chapter 6. Communication; Modbus; Introduction; MODBUS Register Map

AquaTrans™ AT600 User’s Manual 97
Chapter 6. Communication
Chapter 6. Communication
6.1 MODBUS
6.1.1 Introduction
The AT600 flow meter generally follows the standard MODBUS communications protocol defined by the
MODBUS APPLICATION PROTOCOL SPECIFICATION V1.1b, which is available at www.modbus.org. With this
reference as a guide, an operator can use any MODBUS master to communicate with the AT600 flow meter.
For the AT600, there are two limits of this implementation:
1. The AT600 supports only four of the standard function codes. These are Read Holding Registers
(0x03), Read Input Registers (0x04), Write Multiple Registers (0x10), and Read File Record (0x14).
2. The AT600 needs a 15 ms gap between Modbus requests. The prime objective of the flow meter is to
measure flow and drive the output, so the Modbus server has a low priority.
6.1.2 MODBUS Register Map
Table 7: MODBUS Register Map
Register
(in Hex)
Register (in
Decimal)
Access Level Description RO/RW Format
100 100 256 User Product Short Tag RW CHAR * 16
108 264 User Product Long Tag RW CHAR * 32
118 280 User Product message (for HART) RW CHAR * 32
128 296 User Product descriptor (for HART) RW CHAR * 16
140 140 320 User Product Electronic serial
number
RW CHAR * 16
148 328 User Product fixture serial number RW CHAR * 16
150 336 User Product transducer1 serial
number
RW CHAR * 16
158 344 User Product transducer2 serial
number
RW CHAR * 16
300 300 768 RO Main Hardware version RO CHAR * 8
304 772 RO Option Hardware version RO CHAR * 8
308 776 RO Main Software version RO CHAR * 8
500 500 1280 User Global Unit group 1 for Actual
Volumetric
RW INT32
502 1282 User Global Unit group 2 for Day RW INT32
504 1284 User Global Unit group 3 for dB RW INT32
506 1286 User Global Unit group 4 for Density RW INT32
508 1288 User Global Unit group 5 for
Dimension
RW INT32
50A 1290 User Global Unit group 6 for Hz RW INT32
50C 1292 User Global Unit group 7 for
Viscosity
RW INT32