M
ODBUS
I
NSTALLATION
MAN0995_Iss 1_01/16
Touchpoint Plus
Pt. No. 3011M5027_1
5
Modbus Installation Guide
1 Introduction
Modbus is a well supported digital data communication protocol that provides a set of standard commands by which
system data can be communicated.
Touchpoint Plus (TPPL) is supplied with Modbus software as a default, but the Modbus Bus Interface Board (BIB part
number TPPLORTU) is an optional extra for those customers who want to control TPPL via the Modbus protocols.
Normally the BIB is factory or OEM installed, but it can be fitted or replaced in the field by an authorised Honeywell Field
Engineer, or by a qualified person trained in accordance with the TPPL Technical Handbook and these instructions.
1.1 How to Use this Document
This document is provided for the use of Honeywell personnel and Honeywell approved 3
rd
-parties only. Its utilisation
requires a high level of computer skill and a competent knowledge of Industrial Gas Detection Systems and Touchpoint
Plus.
Incorrect use of this document or its procedures could result in unexpected and dangerous consequences. Please read the
Disclaimer
and
Warranty
before proceeding.
This document is designed to be a technical reference source that should be used in conjunction with the following
documents:
•
http://www.honeywellanalytics.com
.Touchpoint Plus Technical Handbook
.
(Search for ‘Touchpoint Plus’ then click
‘Technical Handbook’.)
•
http://modbus.org/docs/PI_MBUS_300.pdf
.
Modicon Modbus Protocol Reference Guide
.
(Check your download
folder if the page appears blank.)
This document uses [Button name] and
Menu>Item>Command
to signify tasks that are carried out on the TPPL
Touchscreen.
1.2 Overview
The TPPL Modbus Interface provides a facility for digital communication between the TPPL and an external computer
system.
Principal features:
•
Operates as a Modbus Remote Terminal Unit (RTU) slave device node.
•
Operates as a Modbus TCP slave device node.
•
Can be used in Modbus Multi-Drop mode.
•
Supports functions 02, 03, 04, 06 and 16 of the Modbus protocol.
•
Provides sensor gas readings and alarm status for Fault, Inhibit, Warning, A1, A2, A3, STEL, LTEL and Rate alarms
from all input channels in the system.
•
Supports commands to Inhibit, Reset and Acknowledge for Modbus RTU only.
•
Asynchronous serial link configurable for baud, bit-rate and parity.
Notes:
•
The Modbus broadcast commands are not supported and will be ignored. i.e. it has no output registers at this time.
•
There are no standard Modbus function formats defined for the communication of data from a gas detection system
so the host computer system must be programmed to interpret the signal and status data made available by TPPL.
•
It is recommended that the host computer system should, as a minimum, be programmed to use Function 02 to
collect alarm and status data from all TPPL channels.
•
Full details of the Modbus protocol can be found in the Modicon Modbus Protocol Reference Guide PI-MBUS-300
mentioned above.
•
The addressing conventions and register values used follow those set by Modicon. The first digit of the on-board
memory address refers to the data type stored in the register and therefore defines the Modbus function command
that should be used when polling it.
