New Cosmos Electric PS-7-M Use and care manual

Instruction Manual No.
GAE-159-00
June 2020
PS-7-M Communication Specifications Guide
Keep this guide for easy reference.
Carefully read this guide prior to use or maintenance for safe
operation.

i
Revision History
Revision Document No. Date Contents of change
00 GAE-159-00 June 2020 Initial issue.

ii
Table of Contents
Revision History ........................................................................................................................................... i
1Introduction ..........................................................................................................................................1
1.1 Related Publications ...................................................................................................................2
1.2 Overview .....................................................................................................................................3
1.3 Trademark Registration ...............................................................................................................3
1.4 Remarks ......................................................................................................................................3
1.5 Symbols Used in this Instruction Manual ....................................................................................4
2Precautions .........................................................................................................................................5
3Unit Structure ......................................................................................................................................6
4Communication Specifications ............................................................................................................7
4.1 Modbus RTU (RS-485) Communication Specifications ..............................................................8
4.2 Modbus TCP (Ethernet) Communication Specifications .............................................................8
5Connection Specifications ...................................................................................................................9
5.1 System Configuration ................................................................................................................10
5.2 Wiring Procedure ......................................................................................................................12
5.2.1 Modbus RTU (RS-485) Wiring Procedure ......................................................................13
5.2.2 Modbus TCP (Ethernet) Wiring Procedure .....................................................................15
5.3 Communication Setup ...............................................................................................................17
5.3.1 DIP Switches ...................................................................................................................17
5.3.2 Status LEDs ....................................................................................................................22
6Communication Protocol ...................................................................................................................23
6.1 Modbus Communication Protocol Overview .............................................................................24
6.1.1 Message Configuration ...................................................................................................24
6.1.2 CRC-16 Calculation (for Modbus RTU only) ..................................................................26
6.1.3 Communication Procedure .............................................................................................26
6.1.4 Modbus RTU Communication Interval ............................................................................28
6.1.5 Differences between Modbus TCP and Modbus RTU Protocols ....................................29
6.2 Function Codes .........................................................................................................................30
6.3 Response in the Event of an Error ............................................................................................31
6.3.1 Error Codes (Exception Codes) ......................................................................................32

iii
6.4 Message Examples ...................................................................................................................33
6.4.1 Function Code 03 (Read Single/Multiple Holding Registers) .........................................33
6.4.2 Function Code 06 (Write Single Holding Register) .........................................................35
6.4.3 Function Code 16 (Write Multiple Holding Registers) .....................................................37
6.4.4 Function Code 23 (Read and Write Multiple Holding Registers) ....................................39
6.4.5 Exception Response (Response in the event of an error) ..............................................41
6.5 Register Address Map ...............................................................................................................42
7Device Status Information .................................................................................................................49
7.1 Gas Alarm Operation ................................................................................................................50
7.2 Trouble Alarm Operation (Fault Alarm Operation) ....................................................................51
7.3 Test Mode Setup and Operation ...............................................................................................52
7.4 Maintenance Mode Setup and Operation .................................................................................53
7.5 Full Scale Codes .......................................................................................................................55
8Troubleshooting .................................................................................................................................56

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1 Introduction
Thank you for purchasing the New Cosmos PS-7-M series extractive pump gas detector
(hereinafter “detector” or “product”).
This detector consists of a main unit and a base unit. A main unit includes a display, a pump and
a sensor, while a base unit has external communication terminals to connect to external devices.
This product supports RS-485 and Ethernet communications.

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1.1 Related Publications
The following documents have been prepared to guide your installation and use of this product.
1. PS-7-M series gas detector’s instruction manual (Doc.No.GAE-138-xx)
This manual provides the following information to ensure safe use of the product.
 Safety precautions
 Installation and wiring
 Basic configuration, block diagram, unit dimensions and components
 Operation and mode setting
 Maintenance, parts replacement, and action to take in the event of a failure
One manual is provided per system, not per unit.
2. PS-7 gas detector’s operation manual for administrators (Doc.No.GAE-019-xx)
This manual is intended for your system administrators/supervisors.
 Password
 Changing settings
All the items set for this product (e.g. alarm set values) are password-protected.
One manual is provided per system, not per unit.
3. PS-7 pyrolyzer’s operation manual (Doc.No.GAE-020-xx)
This manual describes installation and replacement procedure for a pyrolyzer (sold separately).
A manual is provided per system if the unit includes a sensor unit with pyrolyzer.
4. PS-7-M communication specifications guide (Doc.No.GAE-159-xx)
This guide provides the communication specifications and procedure to establish communication with
external devices.
One guide is provided per system, not per unit.
5. PS-7-M IP address setting guide
This guide describes how to set/change the IP address by using a web browser to establish communication
with external devices.
One guide is provided per system, not per unit.

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1.2 Overview
This product uses the Modbus RTU (RS-485) and Modbus TCP (Ethernet) communication protocols. This
guide describes the Modbus interface communication specifications for exterior communication of this
product.
This guide is intended for administrators/supervisors who perform device setups and data collection from the
Modbus master, by connecting the master and the PS-7-M series gas detectors (Modbus slaves) and using
the Modbus protocol function codes and their functions.
For the basic operation of the product, refer to the PS-7-M series gas detector’s instruction manual.
This guide describes the communication specifications and connection method for using the product’s
Modbus communication functions. For the operation and handling of the external Modbus devices that
send/receive data to/from this product, refer to each device’s instruction manual.
1.3 Trademark Registration
Modbus® is a registered trademark of Modicon Inc. (AEG Schneider Automation International S.A.S).
Their company name and product name are also their trademarks and are used in this guide with no TM or “®”
symbol.
1.4 Remarks
Prior to use, carefully read this guide for correct use.
Unauthorized copying and replication of the contents of this guide, in whole or in part, are strictly prohibited.
The contents of this guide are subject to change without notice.
This guide has been prepared with the utmost care. If any incorrect description comes to your notice, please
contact us for correction.

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1.5 Symbols Used in this Instruction Manual
Operators’ safety has been put first in designing this product. However, there exist some
unavoidable risks due to the system characteristics. In this guide, safety symbols are divided into
three categories, Danger, Warning and Caution, depending on the severity and magnitude of the
risks. Carefully read the contents related to the precautions before starting operation or
maintenance work.
This guide uses DANGER, WARNING, CAUTION and NOTE symbols to draw attention to
procedures, materials, methods and processes that require particular attention.
Indicates an imminently hazardous situation that can result in death or serious injury.
Indicates a potentially hazardous situation that may result in death or serious injury.
Indicates a hazardous situation that may result in minor injury or property damage.
Provides supplemental or useful information on product handling.
NOTE

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2 Precautions
Carefully read the following precautions for correct use.
Use this product in accordance with the applicable laws and regulations.
Wiring and installation should only be performed by a qualified electrician with knowledge of
wiring/installation procedures in accordance with the applicable technical standards.
 This product is not explosion-proof and should not be installed in a hazardous area.
 Ground the product to prevent electric shocks.
 In the event of a gas leak alarm, follow safety procedures in accordance with your
company's regulations.
 Do not disassemble, modify, or alter the structure of the product or its electrical circuits;
doing so may compromise product performance.
 This product is not drip-proof and should be kept away from splashing water or rain.

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3 Unit Structure
The PS-7-M gas detector consists of a main unit and a base unit.
For the details on the main and base units and other parts of the detector, refer to the PS-7-M series
gas detector’s instruction manual.
Item Component Description/Function
1 Main unit Includes a display, a pump and a sensor.
2 Base unit Used for wiring and tubing.
Includes two terminal blocks for exterior communication.

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4 Communication Specifications
This chapter describes the communication specifications for this product.
Single-master-multiple-slave (SMMS) communication method is used for a system configuration in
which Modbus slaves (PS-7-M series gas detectors) can send/receive data to/from the Modbus
master.
It is assumed that the Modbus master (high-order device) is a personal computer, a programmable
logic controller (PLC), or a fieldbus controller in case of Modbus TCP.

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4.1 Modbus RTU (RS-485) Communication Specifications
Modbus RTU (RS-485) communication specifications
Item Specifications
Communication protocol Modbus
Communication specifications RS-485 interface
Communication method Two-wire half-duplex asynchronous
System configuration Single-Master-Multiple-Slave (SMMS)
Multi-drop
Data format Modbus RTU mode (hexadecimal number (hex code))
Start bit: 1 bit
Data length: 8 bits (fixed) (LSB first)
Stop bit: 1 bit (fixed)
Parity bit: No parity (fixed)
Communication speed Fixed at 9600 bps
Physical layer protocol ANSI/EIA/TIA RS-485
Number of connected devices Up to 32 units including master
Maximum transmission distance 1.2km when the communication speed is 9600 bps
Terminal resistance 120 Ohm
Can be set to on/off with switch
Error checking method CRC-16
4.2 Modbus TCP (Ethernet) Communication Specifications
Modbus TCP (Ethernet) communication specifications.
Item Specifications
Communication protocol Modbus (TCP/IP)
Communication specifications Ethernet
Communication interface RJ-45 Ethernet IEEE 802.3af/ANSI X3.263
System configuration Single-Master-Multiple-Slave (SMMS)
Port No. No.502 (fixed: Modbus)
Communication speed Max. 10 Mbps/100 Mbps
Physical layer protocol 100BASE-TX
Number of connected devices Up to 254 units
Maximum transmission distance 100 m (distance up to the switching hub)
Applicable cable Unshielded Twisted Pair (UTP) cable
(Category: 5e or higher)
IP address 192.168.100.1 (by default when shipped out)
Can be changed from the base unit or web browser.

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5 Connection Specifications
This chapter describes the connection specifications for this product.

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5.1 System Configuration
Typical communication system configurations are given below as examples.
(1) Typical Modbus RTU (RS-485) configuration
Wire multiple slaves in series (multi-drop wiring).
Use a 120 Ohm terminal resistor at each end of the communication line.
There is a terminal resistor switch on the base unit. Set the switch to the ON position when the
terminal resistors are used at both ends of the line (one resistor at each end).
Maste
r
RS-485
(MODBUS RTU)
＋ －
＋－ ＋－＋－＋ －
RS - 485
(
＋
)
RS
- 485
(
－
)
G
G
G
G
G
120 terminal
resistor is on.
120 terminal resistor
Unit ID: 1 Unit ID: 2 Unit ID: 3 Unit ID: N
N: 7 to 254
Slaves
(The maximum number of connected slaves is 31)

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(2) Typical Modbus TCP (Ethernet) configuration
*1. If the switching hub is not PoE-compliant, provide 24 VDC to PS-7-M units.
*2. In case of using a fieldbus controller as a Modbus TCP master.
Maste
r
L 2- Switch
PoE-HUB *1
Slaves
Fieldbus controlle
r
*2
Ethernet
(
MODBUS TCP
)
PoE-HUB *1
Unit ID: 1
Unit ID: 2
Unit ID: 3
Unit ID: 4
Unit ID: 5
Unit ID: 6
Unit ID: N
N: 7 to 254
NOTE

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5.2 Wiring Procedure
This section explains how to establish a Modbus (RS-485 or Ethernet) network
.
For detailed wiring procedure, refer to the PS-7-M series gas detector’s instruction manual.
Turn off the gas detector before wiring to prevent electric shocks.
 For precautions to be taken while wiring other than the Modbus terminals wiring, refer to 6.
“Installation and Wiring” of the PS-7-M series gas detector’s instruction manual.
 Before powering on the unit, ensure the wiring is correct by referring to 6-1. “Wiring
Procedure” of the PS-7-M series gas detector’s instruction manual and the delivery
specifications if any.
 The analog output line and power line of the gas detector are not isolated from each other.
When using with external devices, provide isolation to prevent noise from other power lines
from interfering with the analog output of the detector.
 When wiring, place wires to avoid potential noise sources (e.g. large power transformers,
motors, and powers supply units).
 Keep the connection cables (power and signal lines from the detector) away from other
power lines.
 When wiring, place wires to avoid mechanical stress on the wiring.

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グロメット
RS-485
通信用端子
終端抵抗
スイッチ
5.2.1 Modbus RTU (RS-485) Wiring Procedure
Establish the Modbus RTU (RS-485) communication by taking the following steps.
When using the 24 VDC power supply, ensure that the power supply is 24 VDC 10%.
Applicable cables: Dia.8–11mm x 2pcs. Use appropriate cables for the installation environment.
1) Run a RS-485 digital signal cable thru the grommet (located at the bottom of the base unit), and
connect the cable wires to their corresponding RS-485 terminals.
Component Marking
on board Function Recommended cable
RS-485
terminals A RS-485 (＋) IN/OUT
2-core shielded twisted pair cable
B RS-485 (－)
IN/OUT
GND Shielded
Grommet
Terminal resisto
r
switch
RS-485 terminals

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2) Run a power cable thru the grommet (located at the bottom of the base unit), and connect the
cable wires to their corresponding power terminals
Component Marking
on board Function Recommended cable
Power terminals
(Thread size: M3) P Polarity: ＋ Power input (24 VDC)
2-core CVV cable
N Polarity: －
Power input (24 VDC)
 Single-point grounding (grounding at a single point) is mandatory. When the
cable shield from the gas detector is grounded on the power supply side, DO
NOT ground the shielded cable to the Earth terminal located inside the gas
detector (on the terminal block for power cable) to avoid 2-point grounding.
 If used in a place exposed to electrical noises, use a shielded twisted pair (STP)
cable. When using STP cable, provide signal grounding so that all the
connected devices are ground-looped (ground continuity) to avoid noise
interference due to ground discontinuity.
 Set the terminal resistor switch (located on the base unit) to the ON position
when terminal resistors are used at both ends of the circuit.
3) Perform the communication setup (select the “RS485” mode and set the unit ID with the DIP
switches (mode change switch and address setting switches). Refer to pages 19 and 20 for the
procedure).
4) Set the base unit power switch to the ON position.
NOTE
Power terminals

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5.2.2 Modbus TCP (Ethernet) Wiring Procedure
Establish the Modbus TCP (Ethernet) communication by taking the following steps.
 When using the 24 VDC power supply, ensure that the power is 24 VDC 10%.
 When using the PoE power supply, ensure that the LAN cable is securely connected.
Bottom view of base unit
1) Connect the LAN cable to the RJ-45 jack on the bottom of the base unit.
Component Function Applicable cables
RJ-45 jack 8P8C
Ethernet and PoE
＋Power Device port
100BASE-TX unshielded twisted pair (UTP) cable
Category: 5e or greater
Cable length: Max.100 m (distance to HUB)
When using a PoE-compliant switching hub (PoE HUB)
Go to step 2).
Turn off the PoE before disconnecting the LAN cable from the RJ-45 jack.
When using a non-PoE-compliant switching hub (PoE HUB)
24 VDC power supply is required.
Run the power cable thru the grommet and connect the cable wires to their corresponding power
terminals (located on the base unit).
Grommet
RJ-4 jack

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 Single-point grounding (grounding at a single point) is mandatory. When the
cable shield from the gas detector is grounded on the power supply side, DO
NOT ground the shielded cable to the Earth terminal located inside the gas
detector (on the terminal block for power cable) to avoid 2-point grounding.
 If used in a place exposed to electrical noises, use a shielded twisted pair (STP)
cable.
2) Perform the communication setup (select “DY” or “ST”, select the “ETHERNET” mode, and set
the 4th value of the IP address with the DIP switches. Refer to pages 19 to 21 for the
procedure.)
3) Set the base unit power switch to the ON position.
NOTE