Siemens CS 275 manual Interface module for 20-m local bus N-V.24, Description

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Interface module for 20-m local bus (N-V.24)

Description

1LED F (red), signals faults (line protocol faulty, receiver memory overflow)

2 LEDs (green)

D signals ”Data transfer on bus”

M signals ”Interface module has master function” T signals ”Bus processor busy”

B indicates setting of interface module on bus B A indicates setting of interface module on bus A

3 Reset key RS

4 Front plug X3 for connection of a non-Siemens computer via V.24 or 20-mA current loop interface

5 Front plug X4 for connection to the 20-m local bus 6 Jumpers for function and address settings

Fig. 4/4 Interface module for 20-m local bus (N-V.24)

voltage +5 V is loaded with 2.4 A per N-V. 24 module thereby. The number of useable interface modules N-V.24 is therefore restricted.

Possible plug-in slots: Slot for I/O module

In the AS 235 automation system (max. 2 modules N-V.24 per system (basic unit or extension unit)

In the AS 235 K automation system (max. 2 modules N-V.24 per system (basic unit)

In the AS 235 H automation system (max. 1 module N-V.24 per extension unit with 5-V module.)

Use of the N-V.24 interface module in the ES 100 K extension system or in the AS 215 automation system is not allowed.

Interfaces for non-Siemens computer

(alternatively at front plug X3)

V.24 interface

T x D	Transmitted data
	Information is sent to the peripheral device via this line
R x D	Received data
	Information is transferred to the system via this line
DSR	Data set ready
	Input for ”data set ready” message from data circuit
	terminating equipment
CTS	Clear to send
	Input for ”clear to send” message from data circuit ter-
	minating equipment
DTR	Data terminal ready
	Output for operating status message of N-V.24 module
RTS	Request to send
	Output signal, switches the transmitter unit of the data
	circuit terminating equipment
I1,I2	Internal constant-current sources

20-mA current loop interface

R x D Received data

+20 mA: input, -- 20 mA: output T x D Transmitted data

+20 mA: input, -- 20 mA: output

Application

For connection of non-Siemens computers to the CS 275 bus system via a V.24 or 20-mA current loop interface.

The external computer must have a V.24 or 20-mA current loop interface. Coupling software is required in the external computer to handle communication with the interface module N-V.24.

The data transmission rate can be adapted to the requirements between 110 bit/s and 9600 bit/s; for example, 120 measured values/s can be transmitted at a data transfer rate of 9600 bit/s via the serial interface.

The module handles duties specifically connected with data transmission, including occasional control of data transfer.

Design

Compact subassembly, double height, with 1 base plug and 2 front plugs

Front panel width 30.48 mm = 2 standard slots.

The N-V.24 interface module is plugged into an I/O slot. It does not receive its supply voltage via L+ (DC 24 V) but via the sup- ply voltage +5 V of the I/O bus for the logic. The logic supply

Mode of operation

Communication between TELEPERM M systems and

non-Siemens computers

Data transfer between TELEPERM M systems and a non-Siemens computer via the CS 275 bus system is carried out using the same messages which are used for communication between TELEPERM M systems. The defined types of order (format, coding, acknowledgement mode) and the function of the hardware interface (N-V.24) are described in the Instructions for the interface module N-V.24 and in the Manual ”N-V.24, Cou- pling of non-Siemens computers to the CS 275 Bus System”.

Coupling software must be installed in the external computer which matches the computer to the communication conditions of the N-V.24 interface.

Setting of address

In order to differentiate between the individual interface modules in the autonomous bus system, each interface module must be allocated a so-called participant address. In order to differenti- ate between several autonomous buses connected via bus cou- plers, each interface module must be allocated a bus address. These two addresses are set using plug-in jumpers on the front panel of the interface module.

Siemens PLT 130 . 1994 4/5