GY-TH78 User Manual
This manual covers the temperature and humidity transmitter's display, electrical specifications, wiring and output options. It includes RS485/Modbus RTU data reading, optional analogue outputs, address and baud-rate settings, temperature and humidity limits and offsets, communication troubleshooting and dimensional drawings.
On this page

DongguanYunjieIntelligentTechnologyCo.,
Ltd.
Temperatureandhumidity
sensor
The1stpage,3intotal
Model:GYTH87RS48
TemperatureandhumiditysensorꞏInstruction
1.productfeatures
Thisproductspecifictemperatureandhumiditydigitaltubedisplayfunction,avarietyofsignaloutput,supportfor485
communication,485theuseofpowerisolation,standardmodbusprotocol.Thedeviceaddressandcommunication
baudratecanbeconfiguredviathehostcomputer.Widevoltageinput,withreverseconnectionandsurgeprotection.
2.electricalparameters
Model
Power
supply
Fourline
definition
Brown:PowerPositiveBlack:PowerNegative
Green:485A
Blue:485B
Power
consumption
Accuracy
Humidity
Temperature
Transmitterworkingtemperature
andhumidity
Probeoperating
temperature
Probeworkinghumidity
Temperaturedisplayresolution
HumidityDisplayResolution
Temperatureandhumidity
refreshtime
Longtermstability
Humidity
Temperature
Responsetime
Humidity
≤8s(1m/swindspeed)
Temperature
≤25s(1m/swindspeed)
Outputsignal
RS485(Modbusprotocol)485cablestringwithrecoverable
fuse,withantisurgetemperaturerange
4~20mAcurrenttypeanalog
quantity
Outputsignal(commonground
type3wire
system)(optional)
Humidityrange
0~10Vvoltagetypeanalog
transmission
Outsignal(commongroundtype3
wiresystem)
(Optional)
Temperature
range
Humidityrange
Temperaturedisplayrange
HumidityDisplayRange
Basicparametersof3.
communication
1.Basic
parameters
Encoding
8bitbinary
Databit
8Bits
paritybit
None
Stopbit
1st
place
errorcheck
CRC(RedundancyCheck)
Baudrate
2400/4800/9600canbeset,factorydefault4800bit/s

DongguanYunjieIntelligentTechnologyCo.,
Ltd.
The2ndpage,3intotal
2.Dataframeformat
UsingModbusRTUcommunicationprotocol,
theformatisasfollows:initialstructure≥4
bytesoftime
Addresscode=1byte
Functioncode=1byte
DataArea=Nbytes
Errorchecking=16bitCRCcode
Endstructure≥4bytesoftime
Addresscode:istheaddressofthetransmitter,whichisuniqueinthecommunicationnetwork(factory
default0x01).
Functioncode:thehostcommandfunctioninstruction,thistransmitteronlyusefunctioncode0x03(readregisterdata).
Dataarea:Thedataareaisspecificcommunicationdata.Notethatthehighbyteof16bitsdatais
first!
CRCcode:atwobytecheckcode.
Hostinquiryframestructure:
Address
code
Function
code
registerstartaddress
Registerlength
lowbitofcheckcode
Highbitofcheckcode
1byte
1byte
2bytes
2bytes
1byte
1byte
Slightanswerframestructure:
Address
code
Function
code
Numberofvalidbytes
DataArea1
Seconddataarea
DataAreaN
Verification
code
1byte
1byte
1byte
2bytes
2bytes
2bytes
2bytes
Registeraddress
Registeraddress
Content
Operation
Humidity
Read
only
Temperature
Read
only
Example:Readthetemperatureand
humidityvalueinquiryframeofdevice
address0x01(hexadecimal):
Address
code
Function
code
StartAddress
Datalength
lowbitofcheckcode
Highbitofcheckcode
Answerframe(hex):(e.g.readtemperatureis9.7℃,humidityis48.6%RH)
Address
code
Function
code
ReturnValid
Numberof
bytes
Humidity
value
Temperature
value
Verification
code
Low
Verification
code
High
Temperature
calculation:
Whenthetemperatureislowerthan0℃,thetemperaturedataisuploaded
intheformofcomplement.
Temperature:FF9FH(hex)=97=>temperature
=9.7
℃temperatureandhumiditysensor

DongguanYunjieIntelligentTechnologyCo.,
Ltd.
Temperatureandhumidity
sensor
The3rdpage,3intotal
Humiditycalculation:
Humidity:1E6H(hex)=486=>Humidity=48.6%RH
4.commonproblemsandsolutions
Possiblecausesofnooutputoroutputerrors:
ThecomputerhasaCOMport,andtheselectedportis
incorrect.
②.Baudrateerror.
③.The485busisdisconnected,ortheandBlinesarereversely
connected.
④,thenumberofequipmentistoomuchorthewiringistoolong,shouldbenearbypowersupply,add485booster,atthesametime
increase120Ωterminalresistance.
⑤,USBto485driverisnotinstalledordamaged.
⑥.Equipmentdamage.
5.PChasabriefdescriptionofthefunction
Name
Valuerange
SetDeviceAddress
Setdevicebaudrate
Readthedevicetemperature
value
Readdevicehumidityvalue
Setupperhumiditylimit
Setlowerhumiditylimit
Setuppertemperature
limit
Setlowertemperature
limit
humidityreturn
difference
Temperature
returndifference
Humidity
deviation
Temperature
deviation
6.productsizechart:
Manufacturer:DongguanYunjieIntelligentTechnologyCo.,Ltd.
Address:No.1,No.2,TangxiaSouthErhengRoad,
TangxiaTown,DongguanCity,GuangdongProvince
Tel:076981001219

Readabletextreferenceforsmalllabels
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Temperatureandhumiditysensor
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Powersupply
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Fourlinedefinition
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Brown:PowerPositiveBlack:PowerNegative
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Powerconsumption
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Accuracy
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Humidity
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Temperature
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Transmitterworkingtemperatureandhumidity
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Probeoperatingtemperature
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Temperaturedisplayresolution
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Temperatureandhumidityrefreshtime
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Humidity
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Temperature
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Humidity
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Temperature
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Temperaturerange

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Temperaturedisplayrange
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Basicparametersof3.communication
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Encoding
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None
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Addresscode
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Functioncode
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lowbitofcheckcode
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Highbitofcheckcode
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Addresscode
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Functioncode
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Numberofvalidbytes
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Verificationcode
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Operation
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Humidity
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Readonly
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Temperature
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Readonly
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Addresscode
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Functioncode
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lowbitofcheckcode
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Highbitofcheckcode
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Addresscode
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Functioncode
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Numberofbytes
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Humidityvalue
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Temperaturevalue
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Verificationcode
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Verificationcode
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Temperaturecalculation:
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Temperatureandhumiditysensor
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Humiditycalculation:
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Valuerange
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Readthedevicetemperaturevalue
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Readdevicehumidityvalue
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Setupperhumiditylimit
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Setlowerhumiditylimit
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Setuppertemperaturelimit
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Setlowertemperaturelimit
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humidityreturndifference
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Temperaturereturndifference
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Humiditydeviation
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Temperaturedeviation
