Temperature Monitoring on PID loop at Steel Process


ISA 100 WirelessDirect Reduction Iron (DRI) is one of the processes to reduce oxygen from iron oxide pellets for steel plant. More than 90% of DRI processes use heated LNG as process gas where PID control for temperature or interlock control is of vital importance.


Direct Reduction Iron

Requirement and Background

Reliable temperature measurement without frequent cable replacement is needed.

One of the major problems faced by the user is frequent replacements of cables as those gets degrade faster because of high ambient temperature and process vibrations. These cable replacements increases the operational cost as well as cost of man hours.


Temperature measurement over the radio as part of PID control loops, Interlock control loops and monitoring at DRI process were introduced. (For shaft furnace, gas reformer and other process pipes)

Highly reliable and full redundant wireless system realized this control loop application.

Two pairs of Redundant Access Point YFGW510 with a Duocast1 wireless communication were connected to a pair of Redundant Management Station YFGW410. Redundant Modbus TCP interface for non-Yokogawa DCS2 achieved stress free interoperability.


The installation was completed in 2013 and the measured results for 120 temperature inputs were found satisfactory.

In dense area, out of line of sight devices up to 50m communicated successfully with less than 5% Packet Error Rate.


  • Higher uptime of process
  • Operational cost reduction
  • Risk reduction: cable degradation, noise interference
  • Less installation costs and time: wiring, cable rack, junction box and etc.
Duocast System


This result proved that Yokogawa's high reliable wireless is very effective for DRI process. Deterministic routing algorism makes the communication latency shortest and fully redundant system with Duocast1 system can provide robust control loops. The High Performance "Radio Chip" embedded in these wireless devices helps to achieve High Quality Communications even in dense areas.

After 12 months or more operation, now the customer is considering expanding wireless applications in their site.

  1. Duocast: wireless redundant communication system standardized at ISA100 wirelessTM on double active access points with minimum wireless latency.
  2. The Yokogawa's CENTUM VP R5 or later supports dual-redundant network configuration with YFGW410 field wireless management station. It enables entire system full redundant. Please consult Yokogawa regional sales in case of engaging full redundant ISA100 wireless network system with 3rd party DCS.



  • 钢铁




  • YFGW410现场无线管理站


  • YFGW510/YFGW520现场无线接入点


  • YFGW520 Field Wireless Access Point

    YFGW520 Field Wireless Access Poin has backbone router function based on ISA, and combining this with Field Wireless Management Station (YFGW410) and/or Field Wireless Media Converter (YFGW610) composes the field wireless system.

  • YTA510无线温度变送器

    高性能温度变送器YTA510接收热电偶、RTD、欧姆或DC mV输入信号。该变送器通过无线信号传输过程变量以及设定参数。该变送器采用内置电池,由于无需硬接线,因此可降低安装成本。通信规格以ISA100.11a协议为基础。

  • YTMX580多点输入温度变送器

    YTMX580最多可接收8点测量输入值,如热电偶(8种类型:K、E、J等)或RTD信号(3种类型:Pt100等),并将相应的测量输入值转换为无线信号。它也可以接收DC电压、电阻和4~20 mA DC信号输入。

  • 现场无线



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