VM3209K Hardware Manual

VM3209K New Hardware Manual Version V1.1

Hardware parameters

Specification

Processor32-bit low-power processor
Frequency580Mhz
Power consumption4W
Operating temperature-20~70°C
Storage temperature-30 ~85°C
Working humidity5 – 95%RH
CertificationFCC/CE

Network parameters

Interface speed10/100M Auto
Electrical isolation2KV
Network ProtocolIP/TCP/UDP/DHCP/DHCPD/DNS/HTTP/SNMP
Maximum number of connections4096

RS485 Parameters

Number of ports1
Baud rate300~230400BPS
Data bits5/6/7/8 Bits
Stop bit1/2 Bits
CheckNone/Odd/Event
Buffer4MBytes
InterfaceTerminal(A,B)

Terminal wiring diagram

VM3209K (8 K-type thermocouple inputs)

Terminal outlet wiring method

K-type thermocouple wiring

PT1000 is used for cold junction temperature measurement, so the PT1000 sensor must be connected to the terminal block connected to the K-type thermocouple, as close as possible to the connection point of the K-type thermocouple to reduce the cold junction temperature measurement error.

Thermocouple temperature measurement principle

K- and K+ represent two different metal materials. The A and B terminals are the connection points of these two metal materials and copper and other metal materials. They are located in the normal temperature environment, which is called the cold terminal, and the C point is the measurement point.

Due to the thermoelectric effect, if there is a temperature difference between points A and C, then there will be a voltage difference between points A and C. Similarly, if there is a temperature difference between points B and C, then there will be a voltage difference between points B and C. A voltage difference is generated. Because K+ and K- are two different metal materials, the voltage difference between A and C is not the same as the voltage difference between B and C. Point C is the welding point of K+ and K-. Point C The electric potential is the same, then a voltage difference is formed between A and B, which is the basic principle of thermocouple temperature measurement.

If you want to accurately measure the temperature t1 at point C, you must accurately measure the temperature t0 between points A and B, and t0 is the cold junction temperature. HJ5209K series equipment uses high-precision PT1000 platinum resistance to measure the temperature t0 between points A and B.

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