RS232 synthetic optical fiber converter – CRM/1S
CRM/1S is a RS232 synthetic optical fiber converter, used when the serial link needs to exceed the effective range of copper wiring or pass through an area with electrical interference. It mounts on a 35 mm DIN rail, occupying a single module, and automatically detects data direction and baud rates up to 250 kbps, allowing it to be integrated into an existing system without any configuration or DIP switches.
The screw-type connector greatly simplifies installation; no specialized tools are required for fiber termination.
FAQ
What is the maximum transmission distance?
100 m per link, like all CLE synthetic fiber products. Beyond that distance, glass fiber is required: CRM/1V performs the same function and supports distances up to 2000 m.
Does it require a dedicated power supply?
No. It accepts a wide range of low-voltage AC and DC power sources, so it is typically powered by whatever is already in the control panel.
Does it work with Modbus?
Yes, and with any other protocol over RS485. It operates by electrical levels and does not interpret the protocol, so it remains transparent even on a bus carrying multiple protocols simultaneously.
Description
CRM/1S is a RS232 synthetic optical fiber converter that converts RS232 electrical serial bus standard to plastic optical fiber with a screw-type connector. It can be used to extend the transmission distance of a serial communication or to isolate network branches. It can be mounted on a control panel with a 35 mm DIN rail and it’s very compact, only 1 DIN module.
CRM/1S RS232 synthetic optical fiber converter accepts a wide range of low-voltage AC and DC power supplies; it is fully Plug & Play and requires no drivers or DIP switches. The RS232 serial interface operates in full-duplex mode and automatically detects the transmission speed up to 250 kbps, making it easy to install in any new or existing system.
What is an RS232 to optical fiber converter used for?
A RS232 synthetic optical fiber converter is typically used to integrate multi-mode optical fiber links into a RS232 communication line. There are also environments where electrical equipment is prohibited, such as swimming pools, saunas, and buildings at risk of fire, where fiber optics therefore become necessary.
The transmission speed is certainly more limited than glass fiber, but it is still more than sufficient for the few Mbps required in industrial applications. In building automation, controlling modules on an RS232 bus requires a few hundred kbps, and synthetic optical fiber is definitely recommended for isolating different zones of a system.
Optical fiber or copper?
In a system, it is good practice to install a RS232 synthetic optical fiber converter at the beginning of a multimode fiber run, and a repeater such as the TSS/1R on each floor. This helps reduce issues related to ground differences or potential power surges in the power supply. Fiber optics are perfect electrical insulators and therefore protect the RS232 bus from the propagation of lightning strikes or other atmospheric discharges.
Fiber optics isolate various branches of a network, such as the floors of a hotel or sections of a photovoltaic system, from electromagnetic interference (EMI) and power surges. Electromagnetic interference is common in these environments. Therefore, it is good practice to install two or more optical-to-electrical converters to ensure signal integrity.
Furthermore, a RS232 synthetic optical fiber converter allows for the regeneration of the electrical signal, thereby improving communication quality.
Protocol
CRM/1S RS232 synthetic optical fiber converter is completely independent of the protocol used. This means that the converter is transparent to the communication and can be used with protocols such as Modbus, BACnet, or any proprietary protocol.
This is possible because the converter operates at the logical levels, rather than at the protocol level itself. Therefore, this RS232 synthetic optical fiber converter can also be used in complex networks where multiple protocols are present simultaneously on the same RS485 bus.
Ease of installation
Multi-mode synthetic optical fiber has several advantages over glass fiber; for example, it is more economical and easier to install. It does not need to be terminated; simply use a sharp utility knife to make a clean cut at the ends.
The maximum recommended transmission distance for synthetic optical fiber is 100 m. As long as you stay within these specifications, use good-quality plastic optical fiber, and maintain appropriate bend radius, simply cut the fiber as indicated. Then simply insert the fiber into the adapter and gently screw the connector on with your fingers, no special tools are needed. There’s no need to over-tighten the connectors, as this risks breaking them or damaging the fiber. This speeds up installation and maintenance, which can even be performed by non-specialized personnel.
In more challenging situations, where a few extra meters can make a difference, or where the fiber is not of the highest quality, additional steps may be necessary to minimize insertion loss. You can polish the ends with fine-grit sandpaper, although this is not necessary in the vast majority of cases.
Versatility
This RS232 synthetic optical fiber converter is available with other combinations of serial and fiber optic standards, or with a 230 V power supply. The CRM/1V and CRM/1Q converters, for example, accept glass fiber with a bayonet connector or synthetic fiber with a Versatile Link connector, respectively. CMM/1S and CFM/1S, on the other hand, are suitable for various serial standards, namely RS485 and RS422.
The CRP/1S RS232 synthetic optical fiber converter is functionally identical to CRM/1S but operates on 230 V AC. All combinations of serial standards, optical fiber types, and power supply options are available in the catalog; however, special requests (such as higher data rates) can be made via the contact form.
Technical Specifications
Main features
| Power supply | 9 – 24 V AC 48/62 Hz 9 – 30 V DC |
|---|---|
| Power consumption | 1 W |
| Serial transmission data rate | 0 – 250 kbps (automatic) – higher data rates on request |
RS232
| Communication type | Full duplex |
|---|---|
| RX input voltage | 1.5 V low input threshold – 1.8 V high input threshold (± 25 V max) |
| TX output voltage | ± 5 V (± 5.4 V max) |
| ESD performance RX / TX | ± 15 kV (Human Body Model) – ± 8 kV IEC61000-4-2 contact discharge |
Screw
| Optical fiber type | Synthetic: POF 2.2 mm – Core 1 mm |
|---|---|
| Maximum transmission distance | 100 m |
| Wavelength | 650 nm |
Mechanical features
| DIN Rail | 1 module |
|---|---|
| Dimensions | 90 mm x 18 mm x 57 mm |
| Weight | 52 g |
Working conditions
| Degree of protection | IP20 |
|---|---|
| Operating temperature | -20 °C to +50 °C |
| Storage temperature | -40 °C to +80 °C |
