VEICHI VC-4TC Thermocouple Type Temperature Input Module User Manual

Thank you for purchasing the VC-4TC thermocouple type temperature input module developed and manufactured by Suzhou VEICHI Electric Technology Co., Ltd. Before using our VC series PLC products, please read this manual carefully in order to have a clearer understanding of the product features and to install and use it correctly. You can make full use of the rich functions of this product for a safer application.

? Tip: Please read the operating instructions, precautions and cautions carefully before starting to use the product in order to reduce the risk of accidents. Personnel responsible for the installation and operation of the product must be strictly trained to comply with the safety codes of the relevant industry, strictly observe the relevant equipment precautions and special safety instructions provided in this manual, and carry out all operations of the equipment in accordance with the correct operating methods.

1 Interface description

1.1 Interface description

The expansion interface and user terminals of the VC-4TC are covered with flaps. Opening each cover reveals the expansion interface and user terminals.

Figure 1-1 Appearance of the module interface. This diagram shows the VEICHI VC-4TC module. It features a terminal cover, status indicators labeled RUN and ERR, a wiring terminal area, an extension female socket, an extended male plug, a product label, a sliding snap, and DIN slot clips.

Figure 1-2 Module interface terminal diagram. This diagram shows the numbered terminals on the VC-4TC module, from 1 to 18, with markings such as 24V, COM, L1+, L1-, L2+, L2-, L3+, L3-, L4+, L4-, and reserved terminals 11-18.

1.2 Product information

Figure 1-2 Product type description. This diagram explains the product code VC-4TC: 'VC' signifies VEICHI Programmable controller, '4' indicates 4 channels, and 'TC' signifies Thermocouple input modules.

1.3 Definition of terminal

No.	Marking	Description	No.	Marking	Description
1	24V	Analogue power supply 24V positive	2	COM	Analogue power supply 24V negative
3	L1+	Channel 1 thermocouple positive	4	L1-	Channel 1 thermocouple negative
5	L2+	Channel 2 thermocouple positive	6	L2-	Channel 2 thermocouple negative
7	L3+	Channel 3 thermocouple positive	8	L3-	Channel 3 thermocouple negative
9	L4+	Channel 4 thermocouple positive	10	L4-	Channel 4 thermocouple negative
11~18	Reserved

1.4 Access system

The VC-4TC is used in VC series programmable controller systems and can be plugged into the system by hardwiring. It connects to the expansion interface of the main module or any expansion module in the system.

Once connected, the VC-4TC's expansion interface can also be used to connect other VC series expansion modules, such as IO expansion modules, VC-4DA, VC-4PT, and other VC-4TC modules. The number of expansion modules is limited by the main module's power supply capabilities, as detailed in section 4.7 of the VC Series Programmable Controller User Manual.

Figure 1-4 Schematic diagram of the connection of the VC-4TC to the main module and other expansion modules. This diagram illustrates how to connect the VC-4TC module to a main module or another expansion module by pushing it into the expansion interface. It shows the "Push to the right" and "Push to the left" actions for insertion and removal.

1.5 Wiring instruction

User terminal wiring requirements are shown in Figure 1-4. When wiring, pay attention to the following 7 aspects. The diagrams indicate the six aspects that must be taken into account when wiring.

Figure 1-5 Diagram of VC-4TC user terminal wiring. This diagram shows the wiring connections for the VC-4TC module. It includes connections for Thermocouples (labeled L1+, L1-, L2+, L2-, L3+, L3-, L4+, L4-), power supply (24V+, 24V-, DC24V±10% 50mA), and ground (PGND, AGND). It also shows connections to CH1, CH2, CH4, and internal components like DC/DC converter, +5V, and -5V. The diagram is annotated with numbered points ① through ⑥, indicating aspects to consider during wiring.

The thermocouple signal is recommended to be connected via a shielded compensation cable, routed away from power lines to avoid electrical interference. Long compensation cables can be susceptible to noise; cables less than 100 meters are recommended. Impedance in the cable can cause errors, resolvable by characteristic adjustment (Section 3).
If excessive electrical interference is present, connect the shield ground to earth.
Ground the PE terminal of the switching power supply properly.
The analogue power supply can be the main module's auxiliary 24Vdc output or another suitable power supply.
Short the positive and negative terminals of unused channels to prevent incorrect data detection.
Terminals can be externally expanded if all multiplexed thermocouples need to be connected to the shield.

2 Instructions for use

2.1 Power indicator

Project	Indicator
Analog circuits	24Vdc (±10%) max. allowable ripple voltage 5%, 55mA (from mains module or external power supply)
Digital Circuit	5Vdc, 70mA (from the main module)

2.2 Performance indicator

Project	Indicator (Celsius (°C))	Indicator (Fahrenheit (°F))
Number of I/O points occupied	No
Input signal	Thermocouples: types K, J, E, N, T, R, S (all 7 types available for each channel), 4 channels in total.
Conversion speed	(240±2%) ms × 4 channels (no conversion for channels not in use)
Rated temperature range	Type K: -100°C ~ 1200°C	Type K: -148°F ~ 2192°F
	Type J: -100°C ~ 1000°C	Type J: -148°F ~ 1832°F
	Type E: -100°C ~ 1000°C	Type E: -148°F ~ 1832°F
	Type N: -100°C ~ 1200°C	Type N: -148°F ~ 2192°F
	Type T: -200°C ~ 400°C	Type T: -328°F ~ 752°F
	Type R: 0°C ~ 1600°C	Type R: 32°F ~ 2912°F
	Type S: 0°C ~ 1600°C	Type S: 32°F ~ 2912°F
Digital output	Type K: -1000 ~ 12000	Type K: -1480 ~ 21920
	Type J: -1000 ~ 10000	Type J: -1480 ~ 18320
	Type E: -1000 ~ 10000	Type E: -1480 ~ 18320
	Type N: -1000 ~ 12000	Type N: -1480 ~ 21920
	Type T: -2000 ~ 4000	Type T: -3280 ~ 7520
	Type R: 0 ~ 16000	Type R: 320 ~ 29120
	Type S: 0 ~ 16000	Type S: 320 ~ 29120
Minimum resolution	Type K: 0.8°C	Type K: 1.44°F
	Type J: 0.7°C	Type J: 1.26°F
	Type E: 0.5°C	Type E: 0.9°F
	Type N: 1°C	Type N: 1.8°F
	Type T: 0.2°C	Type T: 0.36°F
	Type R: 1°C	Type R: 1.8°F
	Type S: 1°C	Type S: 1.8°F
Total accuracy correction point	±(0.5% full range + 1°C), pure water condensation point: 0°C/32°F
Isolation	Isolation between analogue and digital circuits with optocouplers. Isolation between the analogue circuit power supply and the 24 Vdc supply by DC/DC.

Note: With the appropriate mode setting, both °C and °F data can be obtained.

2.3 Indicator light description

Project	Description
Signal indicator	RUN status indicator, blinking when normal; ERR error status indicator, illuminated on failure.
Expansion module rear stage interface	Connection of rear modules, hot-swappable not supported.
Expansion module front interface	Connection of front-end modules, hot-swappable not supported.

3 Characteristic settings

(1) The input channel characteristics of the VC-4TC are the linear relationship between the channel analogue input temperature (A) and the channel digital quantity (D), which can be set by the user. Each channel can be understood as the model shown in Figure 3-1. Since it is linear, the characteristics can be determined by two points P0 (A0, D0) and P1 (A1, D1), where D0 is the digital quantity when the analogue input is A0, and D1 is the digital quantity when the analogue input is A1.

Figure 3-1 Schematic diagram of the channel characteristics of the VC-4TC. This diagram shows a "Channel model" with Analog Inputs (A) leading to a Channel, which outputs a Digital Quantity (D). The "Channel Characteristics" graph displays the relationship between A and D, with points P0(A0, D0) and P1(A1, D1) defining the linear characteristic.

(2) Measurement error caused by connection cable impedance can be eliminated by setting channel characteristics. For user convenience, A0 and A1 correspond to [Measured Value 1] and [Measured Value 2], and D0 and D1 correspond to [Standard Value 1] and [Standard Value 2] respectively, as shown in Figure 3-1. Users can adjust (A0,D0) and (A1,D1) to change characteristics. The factory default is (A0,D0) = 0 (external analogue temperature) and (A1,D1) = 12000 (unit: 0.1°C).

Figure 3-2 Corresponding channel characteristics for each mode without changing the D0 and D1 values for each channel. This graph shows the factory default characteristic settings. The axes are labeled A (0.1°C) and D (0.1°C). The line runs from (-1000, -1000) to (12000, 12000), with the default P0 at (0, 0) and P1 at (12000, 12000).

(3) Channel characteristics can be changed by modifying D0 and D1 values. If the VC-4TC measurement value is 5°C (41°F) higher in practice, the error can be eliminated by setting P0 (0, -50) and P1 (12000, 11950) for characteristic adjustment, as shown in Figure 3-3 for an example.

Figure 3-3 Example of characteristic change. This graph illustrates an example of characteristic adjustment. The axes are labeled A (0.1°C) and D (0.1°C). The points are P0 at (-950, -50) and P1 at (12000, 11950), with D0 = -50 and D1 = 11950.

4 Programming example

4.1 Programming example for VC series + VC-4TC module

The following example demonstrates connecting the VC-4TC to position 1 of the expansion module. Channel 1 is configured for thermocouple type K (Celsius), channel 2 for thermocouple type J (Celsius), channel 3 for thermocouple type K (Fahrenheit), and channel 4 is switched off. The average number of points is set to 8, and the average conversion result is received using data registers D1, D3, and D5. Settings are shown in Figures 4-1 to 4-3. Refer to the VC Series Programmable Controllers Programming Reference Manual for further details. Create a new project and configure the hardware.

Figure 4-1 Auto Studio software screenshot. This shows the project manager interface of Auto Studio, displaying a project structure including MMAIN, Extension Modules, and a Module Tree listing VEICHI modules such as VC-4AD, VC-4DA, VC-4TC, etc. The user is instructed to "Select VC-4TC to drag to rail" to configure the hardware.

Double click on the "4TC" module to enter the 4TC setup screen.

Figure 4-1 Basic application channel one setup. This is a VC-4TC Configuration dialog box for Channel 1. It shows fields for Module ID, Module version, Module error status, Cold spot temperature, Temp. mode (Model K, Celsius), Average sampling time (8), Average temp., Current temp., Standard temp. 1 (0), Measured temp. 1 (0), Standard temp. 2 (12000), and Measured temp. 2 (12000). Notes explain the use of default values, 'D' marks for register addresses, and that Celsius degree is used with a unit of 0.1 Celsius degree.

Click on the down arrow icon ▼ for the second channel mode configuration.

Figure 4-2 Basic Application Channel 2 Setup. This VC-4TC Configuration dialog box is for Channel 2. It shows fields for Module ID, Module version, Module error status, Cold spot temperature, Temp. mode (Model J, Fahrenheit), Average sampling time (8), Average temp., Current temp., Standard temp. 1 (0), Measured temp. 1 (0), Standard temp. 2 (12000), and Measured temp. 2 (12000). Similar notes apply regarding default values, 'D' marks, and unit usage.

Click on the down arrow icon ▼ to configure the third channel mode and click on "Confirm" (OK) when finished.

Figure 4-3 Basic application channel three settings. This VC-4TC Configuration dialog box is for Channel 3. It shows fields for Module ID, Module version, Module error status, Cold spot temperature, Temp. mode (Model K, Fahrenheit), Average sampling time (8), Average temp., Current temp., Standard temp. 1 (0), Measured temp. 1 (0), Standard temp. 2 (12000), and Measured temp. 2 (12000). Notes are consistent with previous configurations.

5 Installation

5.1 Mounting dimensions

Figure 5-1 Mounting dimensions (in mm). This diagram shows the physical dimensions of the VC-4TC module, with measurements provided for width (91.7 mm), height (99.2 mm), and depth (40 mm and 32 mm for different parts). It also shows the terminal layout.

5.2 Mounting method

The module is mounted on a 35mm wide DIN slot. The diagram shows how to attach the module by pressing back the DIN slot snap.

Figure 5-2 Module mounting method. This diagram illustrates how to mount the VEICHI VC-4TC module onto a 35mm wide DIN rail. It shows the module's connection interface and indicates the action "Press back the DIN slot snap" to secure it.

6 Operational check

6.1 Routine check

Check that the analogue input wiring meets the requirements (refer to 1.4 Wiring instructions).
Check that the VC-4TC is reliably plugged into the expansion connector.
Check that the 5V and 24V power supplies are not overloaded. Note: The power supply for the digital part of the VC-4TC comes from the main module and is supplied via the expansion interface.
Check the application to ensure that the correct operating method and parameter range has been selected.
Set the main module to which the VC-4TC is connected to RUN status.

6.2 Fault checking

If the VC-4TC is not operating properly, check the following items:

ERR Indicator Status: Check the status of the main module's "ERR" indicator.
- Blinking: Check the connection of the expansion module and the consistency between the configuration model of the special module and the actual connected module model.
- Extinguished: The expansion interface is correctly connected.
Analog Wiring: Check that the wiring is accurate (refer to Figure 1-5).
ERR Indicator Status (Module): Check the status of the module's "ERR" indicator.

If the 24Vdc power supply is normal, then the VC-4TC is faulty.

RUN Indicator Status:

Off: 24Vdc power supply is normal.
Blinking: The VC-4TC is operating normally.

Warranty Information

For Users

The scope of the warranty refers to the programmable controller body.
The warranty period is eighteen months. Products failing or damaged under normal use within this period will be repaired free of charge.
The warranty period starts from the date of manufacture. The machine code determines the warranty period; equipment without a machine code is out of warranty.
A repair fee will be charged even within the warranty period for:
- Failure due to non-operation according to the user manual.
- Damage caused by fire, flooding, abnormal voltage, etc.
- Damage caused by using the programmable controller for a function other than its normal function.
Service charges are based on actual costs. Other contracts take precedence.
Keep this card and present it to the service unit for warranty service.
For problems, contact your agent or Suzhou VEICHI Electric Technology Co., Ltd directly.

Suzhou VEICHI Electric Technology Co., Ltd
China Customer Service Center
Address: No. 1000, Songjia Road, Wuzhong Economic and Technological Development Zone
Tel: 0512-66171988 Fax: 0512-6617-3610
Service hotline: 400-600-0303 website: www.veichi.com
Data version v1.0 filed on July 30, 2021.

VEICHI Product warranty card

Customer information		Product information
Company name:		Product model:
contacts:		Body barcode:
contact number:		Name of agent:

Fault information	Mailing address
Maintenance time and content: Repairer:	Suzhou VEICHI Electric Technology Co., Ltd Address: No. 1000, Songjia Road, Wuzhong Economic and Technological Development Zone

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