GE Industrial Solutions POWER LEADER ModBus Monitor - Manual (Page 7)

POWER LEADER Modbus Monitor
Chapter 1 – Introduction
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Chapter 1
Introduction
Overview
The GE POWER LEADER Modbus Monitor, shown in
Figure 1, is a microprocessor-based device that connects
to an industry-standard Modbus RTU network,
implemented on RS-485 wiring. The Monitor tracks
metering and status information collected by GE
POWER LEADER power management devices and a
variety of third-party power management devices. The
Monitor provides a convenient station for viewing of
data from remote devices.
Figure 1. POWER LEADER Modbus Monitor.
Modbus RTU networks are designed on a master-slave
architecture. Only one master per network is permitted.
The master queries the slaves when it needs their data,
and slave devices may only communicate on the network
in response to a request from the master.
NOTE: In this manual, the term SEGMENT or
MODBUS SEGMENT will refer to a single RS-485
communications network operating under the Modbus
protocol. A Monitor may be connected to one or two
Modbus segments, depending on whether it is a single or
dual port version.
The Monitor can operate in either of two roles. First, it is
capable of acting as a master on one or two Modbus
segments of power management devices, collecting data
from the devices for local display, as shown in Figure 4.
Second, it is capable of behaving as a “second-in-
command” to GE’s Power Management Control System
(PMCS), as shown in Figure 5. In this role, the Monitor
resides on the RS-485 network with other POWER
LEADER devices, performing its monitoring duties but
behaving as a slave device to the PMCS master.
However, if the master is disabled for some reason,
perhaps a computer problem or a power failure at the
host PC, the Monitor will immediately and transparently
assume the role of master to the other devices.
NOTE: The POWER LEADER Modbus Monitor is
compatible only with GE Power Management Control
System software, version 5.1, version 6.0 or greater. It is
not certified to be compatible with any other host
software.
Once installed and wired to control power and network
connections, the Monitor must be configured for
communications (Modbus address, baud rate, etc.) on the
RS-485 network. It must also be configured with the
identity and type of the other network devices. This
configuration is performed using a software application,
the Modbus Monitor Configuration Tool, running on a
PC. When you are ready to download the configuration
to a Monitor, you’ll connect the PC to the
communications port on the Monitor’s front panel using
an RS-232 straight-through cable (provided with
Monitor).