HITACHI PROGRAMMABLE CONTROLLER RESISTANCE TEMPERATURE DETECTIVE INPUT MODULE(EH-PT4) APPLICATION MANUAL NJI-324(X)
WARNING To ensure that the equipment described by this manual. As well as all equipment connected to and used with it, operate satisfactorily and safety, all applicable local and national codes that apply to installing and operating the equipment must be followed. Since codes can vary geographically and can change with time, it is the user’s responsibility to determine which standard and codes apply, and to comply with them.
LIMITED WARRANTY AND IMITATION OF LIABILITY Hitachi Industrial Equipment Systems Co., Ltd. (Hitachi) warrants to the original purchaser that the programmable logic controller (PLC) manufactured by Hitachi is free from defects in material and workmanship under normal use and service.
Copyright 2002 by Hitachi Industrial Equipment Systems Co., Ltd. All Right Reserved – Printed in Japan The Information and/or drawing set forth in this document and all right in and to inventions disclosed herein and patent which might be granted thereon disclosing or employing and the materials, methods, techniques or apparatus described herein are the exclusive property of Hitachi Industrial Equipment Systems Co., Ltd .
Safety Precautions Read this manual and related documents thoroughly before installing, operating, performing preventive maintenance or performing inspection, and be sure to use the unit correctly. Use this product after acquiring adequate knowledge of the unit, all safety information, and all cautionary information. Also, make sure this manual enters the possession of the chief person in charge of safety maintenance. Safety caution items are classified as "Danger" and "Caution" in this document.
2. About wiring REQUIRED l Always perform grounding (FE terminal). If grounding is not performed, there is a risk of electric shocks and malfunctions. CAUTION l Connect power supply that meets rating. If a power supply that does not meet rating is connected, fire may be caused. l The wiring operation should be performed by a qualified personnel. If wiring is performed incorrectly, it may result in fire, damage, or electric shock. 3.
4. About preventive maintenance DANGER l Do not connect the , of the battery in reverse. Also, do not charge, disassemble, heat, place in fire, or short circuit the battery. There is a risk of explosion or fire. PROHIBITED l Do not disassemble or modify the unit. These actions may result in fire or malfunction. CAUTION l Turn off the power supply before removing or attaching module/unit. Electric shock, malfunction or failure may result.
Revision No. Content Date Manual No.
Table of contents 1. Introduction 1-1 to 1-4 1.1 Before Use ･･････････････････････････････････････････････････････････････ 1-2 1.2 Precaution on Use ･･･････････････････････････････････････････････････････ 1-3 1.3 Features ････････････････････････････････････････････････････････････････ 1-3 1.4 Principle of Operation ･･･････････････････････････････････････････････････ 1-4 2. Structure and Nameplate 2-1 2.1 Structure and Name of Each Part ･･････････････････････････････････････････ 2-1 3.
. Example of Programming 10-1 to 10-4 10.1 Example of Programming 1 ････････････････････････････････････････････10-1 10.2 Example of Programming 2 (Offset adjustment) ･････････････････････････10-4 11. Troubleshooting 11-1 11.1 The Allocation Error “41” is indicated in CPU ･･･････････････････････････11-1 11.2 Data Error in a Specific Channel ･･･････････････････････････････････････11-1 11.3 Data Error in All Channels ････････････････････････････････････････････11-1 12. Appendix 12-1 12.
1.Introduction 1. Introduction This manual describes how to operate the EH-PT4 (Resistance Temperature Detective input module) properly, which is one of the special function module of EH-150 Programmable Logic controller(PLC). Carefully read this manual to familiarize yourself with the procedures respectively of installation, operation, and maintenance and inspection. Please be sure to read the related application manuals, too. Table 1.1 Reference Manual list No. 1 Document Manual No.
1.Introduction 1.1 Before Use The resistance temperature detective input module (hear after EH-PT4) has been carefully manufactured, but you are kindly advised to make the following checks on receipt of it. (1) The type and specification of the module are as specified by the order. (2) No damage is caused to the equipment during transport. If any failures is found, contact the sales office. (3) The accessories listed in Table 1.2 are supplied. Table 1.
1.Introduction 1.2 Precautions on Use (1) Before the installation and removal of the module, turn off the power. (2) Before the connection of the external wiring and removal of the terminal board, turn off the power. (3) The terminal board handles fine signals. Therefore upon handling the module or wiring, be careful not to apply a voltage on it by mistake or leave it under the influence by excessive static electricity.
2. Structure and Nameplate 2. Structure and Nameplate 2.1 Structure and Name of Each Part Name and function of each part Type EH-PT4 Weight Approx. 180 g Dimensions(mm) 1) Lock Button 30 95 2) I/O cover 4) Setting Switch 100 3) Terminal Block Name No. 1) Lock button 2) I/O cover 3) Terminal block 4) Setting Switch Function This is used when removing the module from the base unit. After it is installed to the base unit, the fixation can be reinforced using screws.
3.Specification 3. Specification 3.1 Specification list Table 3.1 shows the specifications of EH-PT4. Table 3.1 Specification Item Specification Type Resistance temperature detective EH-PT4 Platinum resistance temperature detective Pt100 (IEC 751) Platinum resistance temperature detective Pt1000 Temperature conversion data Signed 15 bits (In normal state the lowest bit is always “0”.) Accuracy -20 to + 40 °C (Pt100) ± 0.
3.Specification 3.2 Terminal layout and internal circuit Terminal layout Internal circuit No.
4. Block Diagram 4. Block Diagram 4.1 Internal Block Diagram Figure 4.1 shows the internal block diagram. EH-PT4 External wiring A0 control Counter B0 A3 RTD b3 B3 Constant current circuit Each part Switch circuit Photocoupler insulation CPU Bus Timing V/F conversion (Note) ･･･ Linearize Input conversion circuit RTD b0 Internal Power Supply circuit Shielded wire External grounding 24 V DC+ 24 V DC− External power 24V DC Figure 4.
5. External Wiring 5. External Wiring 5.1 Resistance Temperature Detective Connection Method and External Wiring × b0 × RTD × B0 × × × × A1 B1 × External wiring(Note1) Use a shielded cable NC NC b2 × A2 B2 × NC × × b3 × A3 × RTD A0 to 3 : Current terminal B0 to 3: Current terminal b0 to 3: Voltage terminal b1 × RTD A0 Make a short-circuit on unused channel shown as the figure. The temperature data becomes H7FFF.
6. Setting 6. Setting 6.1 Setting of temperature range This module can be set to three temperature ranges by the dip switch shown in below. Table 6.1 Temperature rage setting Temperature Setting switch measurement range ON Pt100 1,2,5 ON -20 to +40 °C OFF Pt100 1 2 3 4 5 6 7 8 ON 3,6 ON -50 to +400 °C OFF Pt1000 1 2 3 4 5 6 7 8 ON 4,7 ON -50 to +400 °C OFF 1 2 3 4 5 6 7 8 Note: Do not use the setting which is not written in the table, because the temperature data becomes undefined.
7. Collection of Temperature Data 7. Collection of Temperate Data 7. 1 I/O Allocation The temperature data of each channel is collected in the CPU as the temperature conversion data corresponding to the temperature. (1) I/O assignment The I/O assignment shall be set as “WX4W" by your programming software or the peripheral equipment. (2) I/O allocation Depending on the module installation position, the temperature conversion data is stored in the word input number shown below.
7. Collection of Temperate Data 7.2 Temperature Data (1) Content of temperature conversion data [range : -50 to +400 °C] (Pt100/ Pt1000) The meaning of the each bit( b0 to b15) of temperature conversion data (in WX**) is as shown below. The sum of the bit “1” is the measured temperature. b15 b14 b13 b12 b11 b10 b9 -800 200 400 50 100 b8 12.5 25 b7 b6 3.125 6.25 b5 b4 0.781 1.563 b3 0.195 0.391 b1 b2 0.0488 0.0977 b0 (°C) 0.
7. Collection of Temperate (2) Content of temperature conversion data [range : -20 to +40 °C] (Pt100) The meaning of the each bit( b0 to b15) of temperature conversion data (in WX**) is as shown below. The sum of the bit “1” is the measured temperature. b15 b14 b13 b12 b11 b10 b9 -80 20 5 1.25 10 40 b8 2.5 b7 b6 0.3125 0.625 b5 0.78125 0.15625 b4 b3 b2 b1 b0 0.1953125 0.0488281 0.390625 (°C) 0.0976562 0.
7. Collection of Temperate Data 7.3 Example of Calculation The program shown below as an example converts the temperature conversion data in WR0 to BCD 4 digit data in WM6. In case the temperature is minus, the bit internal output R0 will be turned on.
7.Collection of Temperature Data 7.4 Correspondence Table between Temperature and Temperature Data (1)Pt100/Pt1000 -50 to +400 ºC range Table 7.4.
7.Collection of Temperature Data (1)Pt100 -20 to +40℃ range T a b l e 7 . 4 . 2 P t 1 0 0 - 5 0 t o + 4 0 ºC r a n g e T e m p e r a t u r e c o n v e r s i o n d a t a Temperature ( ºC) Note1) Decimal data Hexadecimal data Pt100 resistance (Ω) -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 55296 57344 59392 61440 63488 0 2048 4096 6144 8192 10240 12288 14336 16384 18432 D800 E000 E800 F000 F800 0000 0800 1000 1800 2000 2800 3000 3800 4000 4800 90.19 92.16 94.12 96.09 98.04 100.00 101.95 103.90 105.
8. Error Deception Processing 8. Error Detection Processing 8.1 Measured Temperature Range over (1)Interlock If temperate conversion data is over the measuring range or current terminal wiring is disconnected, the temperature conversion data becomes H7FFF. After this data is read, it is necessary to make a program externally for the treatment for an error.
8. Error Detection Processing 8.2 Treatment for a Sudden Change of Temperature Conversion Data When the temperature conversion data is changed suddenly due to the disconnection of external wiring or influence of noise, the system judges it to be an abnormal condition. In the example shown below, every scanned data is read in. If a change of 5ºC(Note) or more from the previously read data is found, the condition is judged to be abnormal and data is aborted. Note: Change each value to your system.
9. Mounting 9. Mounting 9.1 Installation (1) EH-PT4 module can be installed on both the basic base and expansion base. (2) Precaution on installation Upon the installation of the EH-150 series, consider the operability, maintainability and environment. (a) For use at proper ambient temperature range • Secure a sufficient space allowing a good ventilation. • Do not install the module just over a device generating a great amount of heat(such as heater, transformer and large capacity resistor).
9. Mounting 9.4 Precautions on External Wiring Because the external wiring of the EH-PT4 handles fine signals, be sure to use a shielded wire to suppress the influence of external noise and place the wire separately from the power line and signal line of different voltage.
10. Example of Programming 10. Example of Programming 10.1 Example of Programming 1 (1)Control contents (a) The program keeps the temperature of a liquid in a bath 10 to 12ºC higher than that of ambient air temperature. (b) When the temperature difference between the upper part and the lower part of the liquid is 3ºC or higher, the program turns a stirrer on.
10. Example of Programming (3)Program The program stores the temperature data for 4 channels in the internal output. DR0000 = DX0040 (1) DR0002 = DX0042 (2) (3) Data check WM0000 = H00000 SS0 M0000 = WR0000 == H7FFF M0001 = WR0001 == H7FFF M0002 = WR0002 == H7FFF M0003 = WR0003 == H7FFF M0004 = WM0000 <> H0000 When an error is found, the program turns M4 on.
10.Program (10) (11) R002 Y0003 = 1 When R2 is turned on, the program turns the motor error lamp on. Y0004 = 1 Turn on any one of R1, R3, R4, R7 and M4 to turn on the cooler and turn off the heater. R001 R003 Y0002 = 0 R004 R007 M004 (12) R001 Y0001 = 1 Turn on any one of R1, R3 and R4 to light the temperature abnormality lamp. Y0005 = 1 Turn on M4 to abnormality lamp. R003 R004 (13) M004 R005 (14) the data Turn on either R5 or R6 to turn on the heater and turn off the cooler.
10. Program 10.2 Example of Programming 2 (Offset adjustment) The resistance temperature detective itself has an built-in error, therefore an offset error may occur in temperature conversion data. An offset error occurs due to the change with the passage of time also. An example of correction by programming in this case is shown below. However, because an actual offset value is not always a specified value, it cannot be corrected completely.
11. Troubleshooting 11 Troubleshooting If you have some problems, please find the cause according to the following countermeasures. If the problem is not solved despite this countermeasures, contact the sales office. If a spare unit is available, replace and see the condition. 11.1 The Allocation Error “41 ” is indicated in CPU. Error code “41” is “I/O information verify error”. I/O assignment information and actual loading of module do not much. (Error codes are output as a hexadecimal to the WRF000.
12. Appendix 12. Appendix 12.1 Calculation of External Wiring Resistance Assuming that the cross section and length of tinned annealed copper wire are S(mm2), and L(m), the resistance R(Ω ) of the wire is R ≒ 0.01854×L / S For example, for a cable whose cross section is 0.18 mm2 and length is 200 m, the resistance is R ≒ 0.01854×200 / 0.18 = 20.6 Ω Because the current terminal of EH-PT4 doubles in both ways, the resistance also doubles 20.6 Ω × 2 = 41.2 Ω .
