RTU560

Remote Terminal Unit

Connectivity and Setup

Modem 560FSM10

Operation

The 560FSM10 modem is a CCITT V.23 modem with snap-in DIN rail mounting.

The V.23 uses the frequency shift keying (FSK) method. The modem operates in both 2-wire and 4-wire connections.

The operating mode is set by a 12-fold DIP switch. Figure 1 shows the front view of the modem with the components described in the next chapter from top to bottom.

The power connector X1 consists of three terminals for www.ge-drive.com connection to the supply voltages shown in Table 1.

The PE pin must be connected to ground at the installation. The power indicator lights up when power is supplied.

The RJ45 connector X2 forms the RS232-D interface with the signals in Table 2. If the modem is connected to a communication device, the

If the modem is connected to a communication device, an adapter cable must be used to connect the pairs of lines in Table 2.

The RTS indicator lights up when the end device requests to send via the modem.

The DCD indicator lights when the 560FSM10 detects a carrier signal on the line interface. The CTS indicator lights when a carrier is being established.

CTS will be set at the same time. The 20-30ms transmit delay time must be adjusted in the CMU settings.

DIP switch S1 determines the operating mode of the modem. Switch C-1 is reserved for future use.

C-2 establishes a permanent carrier on the line, which is useful in a four-wire full-duplex connection. Table 3 summarises the above carrier modes.

Switch 2-W is used to distinguish between two-wire and four-wire operation of the modem, as shown in Table 4.

In two-wire mode, X3-1 and X3-2 form the terminal NF1 for transmit and receive.

In four-wire mode, X3-1 and X3-2 form transmitter terminal NF1 and X3-3 and X3-4 form receiver terminal NF2. as can be seen in Table 5.

The next three switches belong to the transmitter amplitude (see Table 6). In longer multi-distribution line configurations, the

the centre station modem requires a high amplification factor to receive the signal from the last modem.

In this case, the transmission level of the central station modem can be reduced by 20 dB using the -20 dB switch.

This is done to avoid overloading the receiver of the central station modem. To compensate for the low-pass characteristics of the transmission line

The amplitude of the upper transmission frequency can be increased by 20%, 40% and 60%. If both the 20% and 40% switches are “off”, the amplitude will not increase.

The 560FSM10 has five predefined receiver amplification levels: 0 dB, 10 dB, 20 dB, 30 dB, and 40 dB.

They are set by switches 10 dB to 40 dB (see Table 7).

DIP switches T-T and T-R are turned on when the 560FSM10 is terminated with line impedance.

This is usually the case at both ends of the line. If the modem is connected as a party line between the two ends of the

then these DIP switches must be “off” (see Table 8.) The T-T end connects to the low frequency (LF) line NF1. consisting of terminals X3-1 and X3-2.

T-R terminates to receiver pair NF2 in a four-wire configuration, consisting of terminals X3-3 and X3-4.

The low-frequency signal transformer of the 560FSM10 modem is designed to meet communication line isolation conditions up to 3 kV.

To achieve a higher level of safe electrical isolation between the modem and the communication line, an additional, separate low-frequency signal transformer is required (see Figure 2).