ABBRER 133 Bus Connection Module

About this manual

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Safety information

General

The RER 133 Bus Connection Module acts as an interfacing unit between an RE_54_ host device and a SPA, Modbus or DNP 3.0 system. The RER 133 module converts RS-232 signals to RS-485 signals. RS-485 can be connected by using 2- or 4-wire mode. The RER 133 module is connected by a cable to the RS-232 D-type connector marked X3.2 on the rear panel of the RE_ 54_ host device. RER 133 is not a stand alone device. An RE_ 54_ host device is always required to power the module. No external power supply is supported. RER 133 supports communication speeds from 300 to 19200 bits/s. Collision detection and collision avoidance is supported for communication speeds 4800, 9600 and 19200 bits/s. A RER 133 delivery includes the RER 133 Bus Connection Module, a connection cable (1MRS120542) and this manual.

Principle of operation

The RER 133 Bus Connection Module is designed to work with RE_ 54_ products. The module utilizes the RS-232 communication port located on the rear panel of the RE_ 54_. The module is not designed to be connected to any other ABB product, nor to any third party products.

The RER 133 Bus Connection Module is designed to work with RE_ 54_ products. The module utilizes the RS-232 communication port located on the rear panel of the RE_ 54_. The module is not designed to be connected to any other ABB product, nor to any third party products.

The signal levels and the functionality of the RER 133 module are defined in the RS-485 standard. RER 133 module is a regular type of RS-485 interface, meaning that a maximum of 32 nodes can be connected in a daisy chain type of bus configuration. Collision detection on the RS-485 bus is supported when a maximum of 32 nodes are connected to the same daisy chain. In order for collision detection to operate, the communication speed has to be set to 4800, 9600 or 19200 bits/s. These speeds are set by using the DIP switches on the front of the module. For an example on how to set these DIP switches, please see section ìModule configurationî on page 9. When collision detection is not used, the communication speed does not have to be set

Construction and installation

The RER 133 module is mounted on the side of the RE_ 54_ host device and is connected by the supplied cable to the 9-pin female type D-connector (X3.2) of the RE_ 54_ host device

Only the cable supplied with the RER 133 may be used to connect the RER 133 module to the RE_ 54_.

The RER 133 module consists of a printed circuit board and is housed in a metal case. Because shielded cables and an RS-485 interface is used, special attention must be paid to the grounding. The dimensions of the case are: 95 mm x 101 mm x 30 mm (95 mm x 105 mm x 38 mm with mounting bracket).

Module configuration

The attributes for the RER 133 can be set through the two DIP switches on the front of the module. The DIP switches are labeled S1 and S2.

4 wire mode requires both the 2- and 4- wire switches for pull-down/ termination/pull-up to be set.

5.2. Configuration examples

Interfaces

The RS-485 bus used by SPA, Modbus and DNP 3.0 requires a daisy chain topology. A daisy chain topology means a node-to-node connection, where nodes are chained using cables of minimal length. The cables must be point to point, no stars, rings or other topologies are allowed. The bus must be terminated at both ends using 120Ω resistors. The RER 133 includes as an option the use of internal termination resistors. These resistors are enabled through DIP switch S2. Pull-up and pull-down resistors must be used in one of the nodes, in order for the receivers to be able to determine the state of the bus when it is idle. These resistors can be enabled through DIP switch S2. Please see sections ìModule configurationî on page 9 and ìConfiguration examplesî on page 10 for the correct settings. The RS-232 interface (X1) of the RER 133 module is shown in Fig. 6.-1.

Fig. 6.-1 Pin usage table for the 9-pin D-type connector (X1) The RS-485 interface of the RER 133 module is shown in Fig. 6.-2. The connector (X2) is an 8-pin Weidm¸ller terminal block. If GND (pin 5) is used, then it is required for all other nodes to be isolated as well.

The EIA RS-485 Specification labels the data wires "A" and "B", but many manufacturers label their wires "+" and "-". In our experience, the "+" wire should be connected to the "A" line, and the "-" wire to the "B" line. When wiring RS-485 , use a shielded twisted pair cable with an internal impedance of 100-120Ω. Examples of recommended cables are CAT 5, Belden RS-485 (9841- 9844) and Alpha Wire (Alpha 6222-6230)

The shield of the cables must be directly connected to ground in one of the nodes. In the other nodes the connection should be made via a capacitor, i.e. if the shield of the cable is connected to pin 1 in node 1, all the other nodes must be grounded using pin 2.