VorTek Pro-T, Instruction Manual

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Series M22/M23/M24 Instruction Manual Chapter 4 Serial Communications
M-000-00010 4-9
Modbus Communications
Applicable Flow Meter Models
VorTek Pro-V® Mass Flow Meters, Models M22, M23, and M24 with Modbus
communication protocol and firmware version 4.00.58 and above.
Overview
This document describes the preliminary implementation of the Modbus
communication protocol for use in monitoring common process variables in the
VorTek Pro-V® Vortex flow meter. The physical layer utilizes the half-duplex
RS-485 port, and the Modbus protocol.
Reference Documents
The following documents are available online from www.modbus.org .
Modbus Application Protocol Specification V1.1
Modbus Over Serial Line Specification & Implementation Guide V1.0
Modicon Modbus Protocol Reference Guide PI
– MBUS – 300 Rev. J
Wiring
An RS485 daisy chained network configuration as depicted below is
recommended. Do not use a star, ring, or cluster arrangement.
RS-485 -
RS-485 +
RS-485 GND
RS-485 Master
Vortex Meter
R
S
-4
8
5
-
R
S
-4
8
5
+
R
S
-4
8
5
G
N
D
R
S
-4
8
5
-
R
S
-4
8
5
+
R
S
-4
8
5
G
N
D
Other Device 2, etc.
R
S
-4
8
5
-
R
S
-4
8
5
+
R
S
-4
8
5
G
N
D
Other Device 1
Figure 4-4.RS-485 Wiring (MODBUS)
Pin Labeling (among devices)
“RS -485 –” = “A” = “ TxD-/RxD- ” = “Inverting pin”
“RS -485 + ” = “ B ” = “ TxD+/RxD+ ” = “ Non- Inverting pin”
“RS -485 GND ” = “ GND ” = “G” = “SC” = “Reference”
Warning!
Place controls in manual
mode when making
configuration changes to
the vortex meter.