Grand Meyer MST-91Ai User manual

Wi-Fi thermostat-weather station
MST-91Ai
INSTALLATION GUIDE
EN

MST-91Ai Installation guide EN Rev 1.0
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Contents
Introduction ................................................................................................................................................ 3
Specifications .............................................................................................................................................. 4
Device and wiring diagram ......................................................................................................................... 5
Connection table ........................................................................................................................................ 6
Installation and assembly ........................................................................................................................... 6
Installation of a weather station ........................................................................................................ 6
Installation and connection of sensors .............................................................................................. 7
Connecting to the web interface of the weather station
........................................................................ 10
Reset Wi-Fi settings and access password ............................................................................................... 12
Security measures .................................................................................................................................... 13
Warranty Terms ........................................................................................................................................ 14
Declaration of conformity ........................................................................................................................ 15
Warranty Certificate ................................................................................................................................. 16

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Introduction
Wi-Fi thermostat-weather station MST-91Ai (hereinafter referred to as the weather station) is
designed to control cable anti-icing systems for roofs, open areas, pipelines, and tanks, as well as
any other cable systems for electrical heating.
The weather station was designed using dual-core microprocessor technology using the RTOS
(real-time operating system), which made it possible producing an exceptionally reliable snow
melting system. Using several unique settings and algorithms, our own weather service and
technology for remote access to weather station sensor data, we have created a flexible and
economical next-gen snow melting system.
The weather station has one channel (1 control relay) and can control one heating system.
The weather station supports the following types of sensors:
Sensor type
Name (Article)
Abbreviation
Temperature / surface sensor
Grand Meyer TS-1
TS
Moisture and precipitation sensor
Grand Meyer TS-2
MPS
The weather station can work fully autonomously with the Internet weather service (no sensors
required or using weather service data when sensors are disconnected/unavailable).
The weather station is configured and managed via the integrated web interface.
This interface allows customers to remotely access all the functions and settings of the system. It
is also allowed connecting the weather station to the Telegram messenger for real-time alerts on
various events and control of the weather station (turning the heating section on and off, etc.).

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Specifications
Supply voltage
~100-240V, 50(60)Hz
Power consumption
no more 5W
Number of control channels (relay)
1
Control relay contact current/load
16A/250V
Type of relay contacts
NO(SPDT)
Number of channels of temperature sensors
1
Temperature measuring range
-40ºС …+120ºС
Temperature accuracy
± 1.0ºС
Number of channels of water and precipitation sensors
1 channel:
- 1 sensor MPS
The number of gradations of measurement levels
(sensitivity) of the sensor of water and precipitation
2(0-dry, 1-presence of water
precipitation)
Wi-Fi standard
802.11b/g/n
Wi-Fi Output
+19.9dBm
Wi-Fi frequency range
2.4GHz
Enclosure Rating
IP20
Operating temperature range
-30ºC…+80ºС at humidity up to 80%
Wire cross section of sensor cables connected to the
weather station terminals
Up to 2.5mm²
Wire cross section for control relay and power supply
cables connected to weather station terminals
Up to 2.5mm²
Dimensions
86 (H) mm x 90 (W) mm x 65 (D)mm
Body color
Light gray
Type of mount
DIN-rail
Weight
165g
Internal fuse rating
0.5A
Compatible temperature sensors
Grand Meyer TS-1
Compatible moisture and precipitation sensors
Grand Meyer TS-2

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Device and wiring diagram
Device
LEDs:
Red on when power is applied to the device.
Blue, lit when connected to the Internet.
Buttons:
S – reset Wi-Fi settings and access password.
R – reboot device.
Wiring diagram

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Connection table
Appointment
№ terminal
block
Description
Sensor wire color
Supply
voltage
1
~100/240V (L)
2
~100/240V (N)
Relay
3
Relay(independent contact)
4
Relay(independent contact)
M
7
sensor MPS
Brown
8
sensor MPS
Blue
T
9
sensor TS
Brown
10
sensor TS
White
Installation and assembly
Installation of a weather station
The weather station is mounted on a DIN rail with the special latch is provided on the back cover of
the case. Connections of the heating sections of the system are carried out after their installation and
verification. Power supply of the weather station is performed through the circuit breaker after
checking all the connections. After power-up, the red LED should light up.
When installing a weather station, keep in mind the following restrictions:
The operating temperature range of the weather station is from -30ºC to + 80ºС with
humidity up to 80%.
Protection class IP20, the housing is not waterproof.
Power devices and wires going to them should be located at a distance of at least 10 cm
from the weather station building.
When connecting, the current electrical safety regulations must be observed.
All electrical connections must be made by a qualified electrician.
Attention! The sensor and the sensor cable for water and precipitation are under
voltage!

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Installation and connection of sensors
Correct placement of sensors is particularly important for the correct operation of the system.
Temperature sensor Grand Meyer TS-1 (TS)
The temperature sensor can be used for the following measurements:
• ambient temperature.
• temperature of the heated open area (screed, soil).
• surface temperature of the pipe (tank).
Technical characteristics of the temperature sensor TS
Temperature measuring range
-40ºC…+120ºC
A type
analog
Temperature accuracy
± 1.0 ºC
Active sensor element
NTC (12 кOhm at +25 ºC)
Sensor Cable Length
3m
Maximum cable extension length
100m
Extension cable
2-wire, with copper conductors 0.75mm²
Overall dimensions of the sensor
Ø6mm x 30mm (length)
Weight
100g
The weather station should be connected according to the connection diagram.
Power supply wires should not be located near the sensor cable, as they can interfere. If necessary,
shorten or extend the sensor cable. To connect the sensor cable, use a mounting box with a terminal
block or sets with heat-shrink tubing.
Installing an ambient temperature sensor
The ambient temperature sensor (DT) should be installed inside an empty installation box with a
degree of protection of at least IP65, which can be mounted both on the building itself and on the roof
elements. For a more accurate indication of the ambient temperature, the box with the sensor is
mounted in the places that are most protected from sunlight, outside the range of exhaust ventilation,
attic, etc.
Installation of a temperature sensor for a heated open area (screed, soil)
The temperature sensor of the heated open area (screed, soil) should be mounted in the middle
between the turns of the heating cable at a distance of 40-60 cm from the boundary of the beginning
of the heating circuit. The sensor cable is drawn inside a steel plugged pipe at the end of the pipe or
inside a corrugated tube made of self-extinguishing PVC Ø 16-25mm and connected to the weather
station through an intermediate mounting box.

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Installation of the temperature sensor of the heated pipeline (tank).
The temperature sensor of the heated pipeline (tank) should be installed on the outer wall of the pipe
(tank). The sensor is glued with adhesive aluminum mounting tape and connected to the weather
station through an intermediate mounting box.
Sensor of the presence of melt water and precipitation Grand Meyer TS-2 (MPS)
The sensor is used to detect the presence of melt water and precipitation in the drainage elements
(trays, gutters, valleys, etc.). It is made of a 50-centimeter section of a self-regulating cable, the heat
emission of which varies depending on the environmental properties (temperature, atmospheric
precipitation, melt water and humidity) of the sensor location. The current dependence of the sensor,
proportional to its heat dissipation, is analyzed by a weather station, which, on the basis of the
received data, issues a command to turn on / off the heating sections of the heating system.
Using this sensor, the following benefits can be achieved:
• TS-2 sensor is not influenced by the pollution, therefore, it does not require cleaning.
• The TS-2 sensor cannot be covered with a “snow cap”.
• TS-2 sensor works like the heating sections on the roof, melting snow at the same speed.
Technical characteristics of the MPS sensor
Supply voltage
220V - 230V alternating current, 50(60)Hz
Power consumption
8 - 16 W (in dry condition)
Operating temperature range
-60ºC …+65ºC (+85ºC when off)
A type
self-regulating cable
The number of gradations of precipitation
measurement levels
2(0-dry, 1-presence of water precipitation)
Degree of protection
IP67
Sensor Cable Length
3m
Maximum cable extension length
100m
Extension cable
3-wire shielded, with copper conductors 0.75mm²
Contents of delivery
Sensor TS-2
Weight
220g
Overall dimensions of the active surface of
the sensor
11.5 mm х 500 mm
Connection to the weather station should be carried out according to the connection diagram.
To connect the sensor cable, use a mounting box with a terminal block or sets with heat-shrink
tubing.

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Installation of an MPS sensor on the roof
The sensor should be installed in the gutter as close as possible to the drainpipe or the inlet funnel of
the drainpipe or in places on the roof where there is the greatest likelihood of melt water and
precipitation. It is important that melt water and precipitation fall on the active element of the sensor
and do not interfere with tree branches, neighboring roofs, roof structures, etc. The sensor must be
straightened and fixed with special clamps (included in the delivery package with the weather station)
next to the heating section, without touching it, parallel to it.
Attention! The sensor and the sensor cable for water and precipitation are under
voltage!

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Connecting to the web interface of the weather station
The weather station can operate in two Wi-Fi modes:
• AP access point mode - autonomous operation without connecting to the Internet (in this mode,
the weather station creates its own Wi-Fi network).
• Station mode - work with connecting to another Wi-Fi network and to the Internet.
The first time you turn it on, the weather station will be in AP mode.
Connecting to the web interface when you first turn on the weather station:
1
Connect to a Wi-Fi network with a network name (SSID): Grand
Meyer MST-91Ai.
2
In the address bar of the browser, enter the local IP address of the
weather station: 192.168.7.1