Overview and functions
Both communication modules can convert signals for the line RS 485 such as voltage level, maximum current and power to levels which meet the requirements of intrinsic safety. The modules are powered directly from the PC port or modem. In case this powering is insufficient (battery-powered laptops), DATCOM-Sx can be powered from an external power source.
The powering of the module DATCOM-S1 is indicated by a green LED diode, which is located under a transparent cover. During communication, this diode flashes and, therefore, indicates the data transfer at the same time.
DATCOM-Sx is delivered in a plastic box for the mounting on a DIN rail 35 mm. It is designed for the installation in a enclosed switchboard. Concerning the intrinsic safety, it constitutes a safety barrier without galvanic separation.
Solution for hazardous area
Concerning the intrinsic safety, it constitutes a extending facility, which includes both intrinsically unsafe - port(s) RS232 (connector D-SUB 9 and grey terminal board) and intrinsically safe circuit of a data line RS485 (blue terminal board). DATCOM-Sx shall be located outside explosive area and its output data lines shall be connected to devices by a cable.
The communication module DATCOM-Sx is installed on a DIN rail 35 mm. To ensure intrinsic safety, the module DATCOM-Sx shall be earthed by means of a conductor with the cross diameter of 1.5 mm2. The terminal marked with an earthing mark is used for this purpose. The earthing terminal of the module DATCOM-Sx shall be earthed according to the Article 12.2.4 of the standard ČSN EN 60079-14. For installation in an enclosed switchboard, this requirement can be secured e.g. by connecting the earthing terminal with the conductor PE (after the verification of its parameters specified in the above mentioned Article of the standard).
When connecting the devices on the line RS485, the following requirements shall be met:
- maximum number of communication modules DATCOM-Sx on a line - 4
- maximum number of all devices on a line - 10