Operation; Communications Modes; Rs-485 Modbus Slave; Rs-232 Modbus Slave - Cortalk RMU5 Generic Installation And Configuration Manual

6 Operation

This section describes the operation of the RMU5 as it relates to external controlling and monitoring.

6.1 Communications Modes

The RMU5 may use one or more communications methods to exchange data with a monitoring/controlling host. The
various hosts are described here.

6.1.1 RS-485 MODBUS Slave

Pins 14, 15 and 16 on the main I/O connector may be used to attach a MODBUS master to the RMU5 via RS-485. Pin
14 is ground, pin 15 is DATA+ and pin 16 is DATA-.
UART parameters and slave address are configured as described in section 5.2.1.5. The MODBUS register addresses
default to the values shown in appendix B.

6.1.2 RS-232 MODBUS Slave

Using a DRI1 communications expansion connector adapter board, the RMU5 supports MODBUS over RS-232 signal
levels. The DRI1 adapter board converts the signals on the DA-15S communications expansion connector to a standard
DE-9 pin out. Both DCE (female DE-9) and DTE (male DE-9) connectors are present on the adapter board—only the
pin out and connector are different. The same UART signals are present on both connectors, meaning that only one of
the two connectors may be used at any one time. The adapter board also provides a power source that outputs 10.4 to
14V, depending on whether the RMU5 is operating on main power or backup battery, at a current rating of up to 2.5A.
This power output may be used to power a radio transceiver directly.
Alternatively, the MODBUS master device may be connected directly to the DA-15S connector through a custom cable
with pin outs based on the connector description in Table 4 on page 62. Only TXD, RXD, and GND signals are required.
The UART parameters and slave address are configured as described in section 4. The MODBUS register addresses
default to the values shown in appendix B.

6.1.3 Ethernet MODBUS Slave

The RMU5 may be attached to a standard 10/100Base-T Ethernet network via the RJ-45 connector labeled "Ethernet".
Once the TCP/IP parameters are configured and MODBUS over Ethernet is enabled using RMUSetup, the RMU5 will
respond to standard MODBUS TCP queries over TCP port 502. The same register addresses as in serial MODBUS are
available over Ethernet.

6.1.4 PSTN Dial-up Modem

Through the use of an adapter board (same as the RS-232 MODBUS Slave adapter board mentioned above), it is possible
to attach a standard PSTN dial-up modem to the RMU5. Currently, the RMU5 only communicates with the Mobiltex
Cathodic Monitoring Host application via PSTN modem when PSTN Dial-up Modem is selected as the RS-232 port
function. The specification for the communications is available in a separate document.
Customer requested communications protocols may be added in the future to support other host applications.
MODBUS may be used by configuring the modem to auto-answer, and setting the RS-232 port function to MODBUS
slave. The host then calls the RMU5 modem and initiates the necessary queries to retrieve information from the RMU5.
When finished querying, the host drops the modem call.

6.1.5 MSK Radio Modem

Through the use of an adapter board (same as the RS-232 MODBUS Slave adapter board mentioned above), it is possible
to attach a Mobiltex proprietary digital data radio to the RMU5.
communications expansion adapter board.
The Mobiltex proprietary digital data radio is capable of operating at 1200/2400 MSK modulation. RF power output is
adjustable to 5W maximum. The radio is available in VHF and UHF banding.
The parameters for the RS-232 serial port must be configured in RMU5Setup for this interface type to be operational.

6.1.6 Iridium Satellite

The RMU5 is capable of sending data to a custom host over the Iridium satellite system using an RMU3-S Iridium
satellite modem. The data is sent in a proprietary format which is decodable by the Mobiltex Cathodic Monitoring Host
MOBILTEX® DATA LTD.
Calgary, Alberta
TITLE:
RMU5 Generic Installation and Configuration Guide
DOCUMENT NO.: SHEET:
RMU5-MAN-001
Power for the radio is provided from the
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