Panametrics PanaFlow XMT1000, User Manual, Page: 34 / 80

Appendix B. Modbus communication
B.1 Modbus protocol
In general, the PanaFlow XMT1000 flow meter follows the standard modbus communications protocol defined by the
reference MODBUS APPLICATION PROTOCOL SPECIFICATION V1.1b. This specification is available at www.modbus.org on the
Internet. With this reference as a guide, an operator could use any modbus master to communicate with the flow meter.
Listed below are two limits of this implementation:
• The PanaFlow XMT1000 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).
and
• The flow meter needs a 15 msec gap between modbus requests. The prime objective of the flow meter is to
measure flow, so the modbus server has a low priority.
B.2 Modbus register map
Table 6: XMT1000 modbus register map - revision 4.19
Reg #
in hex
Access
level
Register ID Description Units
RO/
RW
Size in
bytes
Format
Health check + identification (input registers)
210 210 NONE Product type Unitless RO 4 INT32
System real RW
400
System int RW
500 500 Operator eUnit_ActVol
Global unit group 1
for actual volumetric
Unitless RW 4 INT32
502 Operator eUnit_day
Global unit group 2
for day
Unitless RW 4 INT32
504 Operator eUnit_Db
Global unit group 3
for dB
Unitless RW 4 INT32
506 Operator eUnit_Dens
Global unit group 4
for density
Unitless RW 4 INT32
508 Operator eUnit_Diam
Global unit group 5
for dimension
Unitless RW 4 INT32
50A Operator eUnit_Hz
Global unit group 6
for Hz
Unitless RW 4 INT32
50C Operator eUnit_Kv
Global unit group 7
for viscosity
Unitless RW 4 INT32
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