RTscan RT214 2D Barcode Reader Installation Guide

RTscan RT214 2D Barcode Reader

Product Specifications

• Model: RT214
• LED: White LED for illumination, Red LED aimer
• Operating Temperature: Refer to the user manual for details
• Storage Temperature: Refer to the user manual for details
• Humidity: Refer to the user manual for details

Product Usage Instructions

Illumination
The RT214 is equipped with a white LED for supplementary lighting, allowing barcode scanning in low-light conditions. This feature can be toggled On or Off based on your requirements.

Aimer
The device includes a red LED aimer to assist in aligning the barcode within the field of view for efficient scanning. It is recommended to enable the aimer for regular barcode scanning.However, in scenarios with varying background colors or strong light, consider turning off the aimer for optimal performance.

Installation
When installing the RT214, avoid touching the imaging lens to prevent fingerprint marks. Exercise caution when handling the illumination LED to prevent damage. Ensure proper ESD protection and dust prevention measures are in place.

Mounting
Refer to the mechanical mounting dimensions provided in the user manual for the correct installation of the RT214.

Housing Design
The RT214 utilizes a sophisticated optical system. Proper housing design and selection of window material are crucial to maintain performance. Follow guidelines for window placement and material selection.

Introduction

The RT214 is an area image engine for barcode reading. It includes an illumination LED and an aiming LED.
LED Compliance Statement
The RT214 complies with IEC 62471:2006 for LED safety.

The RT214 contains:

• a CMOS image sensor and its lens,
• an LED-based illumination system
• an LED aiming system

Figure 1-1 System Block Diagram

Illumination

The RT214 has a white LED for supplementary lighting, making it possible to scan barcodes even in complete darkness. The illumination can be programmed On or Off.

Aimer

The RT214 contains a red LED aimer to help the user to easily position the target barcode within the engine’s field of view to increase scan efficiency. The aiming pattern can be turned On or Off. It is advisable to turn it on when scanning barcodes in regular circumstances. For applications in the background of different materials and colors or in the strong light or backlight environment, it is advised to turn off the aimer.

Introduction

This chapter explains how to install the RT214, including general requirements, housing design, and physical and optical information.

• Caution: Do not touch the imaging lens when installing the engine. Be careful not to leave fingerprints on the lens.
• Caution: Do not touch the illumination LED during handling. Improper handling may damage the LED.

General Requirements

ESD
ESD protection has been taken into account when designing the RT214. However, due to limited board space, additional ESD protection, such as TVS protection, is not provided on the engine’s I/O interface. It is advised to take corresponding protection measures when integrating the engine.
The engine is shipped in ESD-safe packaging. Always exercise care when handling the engine outside its package. Be sure that grounding wrist straps and properly grounded work areas are used.

Dust and Dirt
The RT214 must be sufficiently enclosed to prevent dust particles from gathering on the lens and circuit board. Dust and other external contaminants will eventually degrade the engine’s performance.

Ambient Environment
The following environmental requirements should be met to ensure good performance of the RT214.

Table 2-1

Thermal Considerations
Electronic components in the RT214 will generate heat during their operation. Operating the RT214 in continuous mode for an extended period may cause temperatures to rise on the CPU, CIS, LEDs, DC/DC, etc. Overheating can degrade image quality and affect scanning performance. Given that, the following precautions should be taken into consideration when integrating the RT214.

• Reserve sufficient space for good air circulation in the design.
• Avoid wrapping the RT214 with thermal insulation materials such as rubber.

External Optical Elements

Do not subject external optical components on the engine to any external force. Do not hold the engine by an external optical component, which may cause the mechanical joints that secure the components to crack or break due to excessive stress.

Mounting

The illustrations below show the mechanical mounting dimensions (unit: mm) for the RT214.

Note: Tolerance of dimension is ±0.15mm.

Housing Design

Note: Conduct an optical analysis for the housing design to ensure optimal scanning and imaging performance.

Housing design should make sure that internal reflections from the aiming and illumination system are not directed back to the engine. The reflections from the housing or window can cause problems. Avoid any highly reflective objects around the engine that can cause bright spots to appear in the captured image. It is recommended to use baffles or matte-finished dark internal housing colors.

Optics

The RT214 uses a sophisticated optical system. An improperly designed internal housing or improper selection of window material can degrade the engine’s performance.

Window Placement
The window should be positioned properly to let the illumination and aiming beams pass through as much as possible and no reflections back into the engine (reflections can degrade the reading performance of the engine).

There are two window placement options.

• Parallel window – Primary option for image engines. The following window distance requirements should be satisfied: The maximum distance is measured from the front of the engine housing to the furthest surface of the window. To reach better reading performance, the distance from the front of the engine housing to the nearest surface of the window should not exceed a (a=0.1mm) and the distance from the front of the engine housing to the furthest surface of the window should not exceed a+d (a=0.1mm, d=2mm), as shown in Figure 2-2.
• Tilted window – This option is for laser/imager engines. For the tilted window distance requirements, please see Table 2-2.

Table 2-2

Window Material and Color
Window material must be clear. Use only cell-cast plastics or optical glass. PMMA and chemically tempered glass are recommended. Window material selected for the engine should meet or exceed the specifications specified in Table 2-3. When using a clear plastic window, it is recommended to apply anti-reflection (AR) coating on it.

• PMMA (Cell-cast acrylic): When fabricated by cell-casting, it has very good optical quality and low initial cost, but the surface must be protected from the environment due to its susceptibility to attack by chemicals, mechanical stresses, and UV light. Reasonably good impact resistance.
• Chemically tempered glass: Glass is a hard material which provides excellent scratch and abrasion resistance. But unannealed glass is brittle. Increased flexibility strength with minimal optical distortion requires chemical tempering. Glass is hard to be cut into odd shapes and cannot be ultrasonically welded.

Table 2-3

Pay extra attention to the light wavelength when using plastic materials. Colored windows are not recommended if the engine is used to scan barcodes on moving objects.

Coatings and Scratch Resistance
Scratch on the window can greatly reduce the performance of the RT214. It is suggested to use abrasion resistant window material or coating.
The following introduces two commonly used types of coatings:

• Anti-reflection coatings: Anti-reflection (AR) coatings can be applied to window surfaces to reduce reflected light from the window back into the engine. Multi-layer AR coatings on windows help to achieve less than 0.5% reflectance, and the covered wavelength is 400-780nm.
• Scratch resistance coatings: Scratch resistance coatings require a degree of greater than 5H in its hardness. Coatings can be applied to plastic surfaces to increase the surfaces’ abrasion and scratch resistance.

Both tempered glass and plastic windows can be AR-coated. However, it is easier and more cost-effective to put an AR coating on the glass than on the plastic.
The AR coating specifications below should be met when using an AR-coated window.
Single side AR coating: 93% minimum transmittance within the spectrum range from 400 nm to 780 nm.
Double-sided AR coating: 97% minimum transmittance within the spectrum range from 400 nm to 780 nm.

Window Size
The window must not block the field of view and should be sized to accommodate the aiming and illumination envelopes shown below.

Horizontal:

Vertical:

Roll, Skew, and Pitch
Three different reading angles, roll, skew and pitch are illustrated in Figure 2-6. Roll refers to rotation around the Z axis, skew to rotation around the X axis and pitch to rotation around the Y axis. For the engine’s technical specifications, please visit the RTscan website or contact your dealer.

Ambient Light
The RT214 shows better performance with ambient light. However, high-frequency pulsed light can result in performance degradation.

Eye Safety
The RT214 has no lasers. It uses LEDs to produce illumination beam. The LEDs are bright, but testing has been done to demonstrate that the engine is safe for its intended application under normal usage conditions. However, the user should avoid looking into the beam.

Power Supply

• Do not power up the RT214 until it is properly connected. Be sure the power is cut off before connecting a cable to or disconnecting a cable from the host interface connector. Hot-plugging could damage the engine.
• Unstable power supply or sharp voltage drops or unreasonably short interval between power-ons may lead to unstable performance of the engine. Do not resupply the power immediately after cutting it off.
• When designing, the user should ensure that the input power of RT214 is fully decoupled. It is recommended to place a 22uF and a 100nF X5R or X7R ceramic capacitor beside the power input pin on the connector which is soldered on the board. The capacitor mounted on the external input power supply is recommended to be controlled within 50uF.
• Ensure that the input power drops below 0.5V before powering the RT214 on again; otherwise, it will lead to abnormal function.

Ripple Noise

To ensure the image quality, a power supply with low ripple noise is needed. Acceptable ripple range (peak-to-peak) :≤100mV

DC Characteristics

Operating Voltage

Table 3-1
T=25°C

Operating Current

Table 3-2
T=25°C

The max impulse current (439mA) when powered on is shown in Figure 3-4. It is recommended that the external VDD should provide at least a current of 500mA. Ensure that the Rdc of the cable is controlled within 0.35Ω by shortening the FPC cable, increasing the power line and ground line width, etc. Avoid using long cables to connect the RT214. Power consumption will result in abnormal function.

I/O Voltage

Table 3-3
VDD=3.3 V, GND =0 V, T=25°C

Note: The high and low level threshold of nTRIG is related to the external voltage VDD. The input low level VIL of nTRIG should be below VDD-1.1, and the input high level VIH should be above VDD-0.4.

Timing Sequence

Power Up Timing Sequence

1. In the diagram above, it takes A+B+C (about 215ms) for the engine to power up: A is bootloader execution time (25ms), B is kernel boot time (5ms) and C is decoding chip initialization time(185ms).
2. D is reset time (300us). If the Reset signal is not operated when powered on, the startup time should be calculated after VCC_3V3 reaches 3.3V.
3. Ensure that all communication interface data has been transmitted before powering off.
4. The RT214 has a 100K pull-up on the nTRIG signal. During the period between power-on and bootloader execution, the user should not lower the nTRIG signal. If nTRIG is set high before power-on, it should meet the duration of E (E=0~1ms) as shown in Figure 3-4. Levels of other signals are kept low during power-on to prevent abnormal function.

Power Down Timing Sequence

Figure 3-8

Note: When powering down the RT214, cut off the power and ensure levels of TXD, RXD, USB_D+, USB_D-, nTRIG, and nRST signals are kept low.

Interface Pinouts

The RT214’s FPC comes out with 12 pins to host:

12-pin definition of the pinout of RT214:

Note: please remember your device’s TXD should be connected to RXD of RT214, and RXD to TXD.

External Circuit Design

Good Read LED Circuit
The circuit below is used to drive an external LED to indicate a good read.

Beeper Circuit
The circuit below is used to drive an external beeper.

Trigger Circuit

The circuit below is used to provide the engine with a signal to trigger a scan and decode session.

The host can adjust the external circuit and its functions based on actual applications. R1 is recommended as 10 K-100 K and R2 as 33Ω. C1 is used to eliminate the vibration of mechanical keys. Generally, 1nF-10nF ceramic capacitors are recommended. When ESD protection is required, an ESD protector can be added to the external circuit threshold shown as being.

When using the external IO port as a trigger output, note that high and low levels must meet the requirements provided in Table 3-3. It is recommended to use the default floating or default pull-up IO port as the trigger pin. If you can only use the default pull-down IO port as the trigger pin, refer to the power-on timing sequence in Figure 3-5. When not triggered, ensure that the pin meets the high-level requirements in Table 3-3.

EVK

The EVK is provided to help users to test and evaluate the RT214, which contains beeper & beeper driver circuit, LED & LED driver circuit, and trigger, TTL-232 to RS-232 converter, RS-232 or USB interfaces, reserved signal debugging interface, etc.

For Any Technical Support, please contact us at: support@rtscan.net

Frequently Asked Questions

• Q: Can the illumination and aimer features be customized?
  A: Yes, both the illumination and aimer functionalities can be programmed to suit specific requirements.
• Q: What precautions should be taken during installation?
  A: Avoid touching the imaging lens or illumination LED, ensure ESD protection, and maintain a dust-free environment for optimal performance.
• Q: What is the recommended window material for the RT214?
  A: Clear cell-cast plastics or optical glass are recommended. PMMA and chemically tempered glass are suitable options. Ensure the window material meets specifications outlined in the user manual.