Siemens 2XV9450-1AR21/2XV9450-1AR48 user manual Connection, Mounting

User Manual SICLOCK DCFRS Industrial Version

2.2 Connection

2.2.1 Target System

The interface between the target system and the antenna is provided by the TTY-RS232 converter. It is connected to the target system via a RS232 interface. The other end of the cable is spit, the 4 wires are provided with wire end ferrules. The AC adapter (output 14V AC) supplied is connected to the white and brown wires. A direct current between 15V and 30V or an alternating current between 10V and 20V can also be connected. There is a rectifier integrated in the converter and therefore there is no need to take the polarity into account. The cable to be laid on site is connected to the yellow and green lead (2-wire shielded, loop resistance less than 150 Ohm).

2.2.2 Antenna

The two antenna connections are connected in the second distribution box with the connecting cable to the TTY-RS232 converter. Here, too, there is no need to take polarity into account. After starting the reception service on the target system, the LED on the antenna must begin to flash in second tact. Then the mounting of the antenna and its alignment can begin.

2.2.3 Cable Shield

The shield of the connection cable laid on site between the TTY-RS232 converter and the antenna should be connected to one cable end low-resistance with the earth. Specially suitable for this are earth bars from switch cabinet or water pipes. Under no circumstances should there be an earth on both sides, as this can result in high potential equalizing currents over the cable shield.

2.3 Mounting

2.3.1 Choice of Location

Before beginning to mount the antenna the location for this should be selected with care. This is significant for the quality of the reception and therefore of the availability of the DCF77 reception signal. It can be at a maximum of 1000 m away from the unit to be synchronized. In selecting the location, the following criteria should be optimized:

•Distance from electric equipment: Every electrical appliance sends out electro-magnetic radiation which impairs reception. The antenna should therefore be set up as far away as possible from electrical appliances. A particularly high disturbance level is caused by monitors, PCs, laser printers, motor drives and neon tubes, and maximum distance should therefore be maintained from such equipment. Care should also be taken that the antenna cable is not laid parallel to the output cables (e.g. supply cable for motors).

• Shielding:Metal objects shield the reception signal and thus impair quality of reception. As great a distance as possible should therefore be maintained to metal surfaces and objects. It should also be noted that under certain circumstances, the steel reinforcement in reinforced concrete weakens the field.

•Alignment to the transmitter: The transmitter which sends out the DCF77 time signal is located near to Frankfurt. The steel which is incorporated in modern buildings weakens the reception signal. In respect of optimum conditions for reception, the place of reception is preferably chosen on the side facing Frankfurt. In addition, the antenna should be mounted as high as possible.

In order to find the optimum location for reception within the industrial premises we offer a survey of the whole plant area. In this way as a rule, at least one location can be found which facilitates problem-free and interference-free DCF77 reception. Just give us a call and we shall be pleased to help you.

2.3.2 Alignment to the Transmitter

As for a radio or television antenna, the DCF77 reception antenna must also be aligned to the transmitter. To assess the quality of reception there is a red LED on the antenna, which lights up briefly every second during interference-free reception. For alignment, the antenna must be connected to the target system as described in chapter 2.2. In addition, the reception service must be started, so that the TTY-RS232 converter is supplied with energy. The antenna frame permits any alignment of the antenna as required.

Order No. 2XV9450-1AR48 Version 1.0 5