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MPA3 V5.4 MOTOR PROTECTION RELAY MANUAL
Issue: R0, CRN: 8168, Date: 11/2010
MPAB009 Rev0
MPA3 V5.4 Motor Protection Relay Manual
Page 16
The RTD temperatures for group 1 and group 2 can be viewed on the ‘Temperature Information’ Page, Level 2,
Positions 1 and 2 respectively. The measurement range is 0°C to 210°C. Values greater than 210°C represent an
error condition as follows:
Error Comment
246
Error code 246 results if the RTD terminals are left
open circuit or the RTD resistance rises above 330

. Unused RTD inputs can be terminated with a
100

resistor (0

C) to avoid the error code.
245
Error code 245 results if the RTD is short-circuited
or its resistance falls below 80

.
The RTD’s will operate correctly if the combined installation cable resistance to the PT-100 RTD is less than 40

.
12
Analogue Output
The optional Monitoring Module (MPA-M) provides an isolated analogue output configurable as 0-20 mA or 4-20 mA.
The output is selected via the ‘ An OP :’ setting (Level 7, Position 24) to continuously monitor one of the following
sections:

Trip Accumulator (20 mA = 100%)
 Average Current (20 mA = 120%)

Earth Leakage (20 mA = 100%)

RTD Temp (0-200 °C) (20 mA = 200°C)

Current Balance (20 mA = 100%)

Phase Voltage (A phase) (20 mA = 120%)
The analogue output status is shown on the ‘MPA I/O Status Information’ Page, Level 5, Position 4. The value
shown for ‘ Analog Out ’ is related to the analogue output current according to:
I
out (mA) = Displayed Value x 8.1458 x 10
-05
13
Communications
When the MPA is ordered with an optional monitoring module a communications port is provided. This allows for the
connection of the MPA to PLC or SCADA systems. Two different monitoring modules are available providing a
choice between RS485 Modbus RTU and EtherNet/IP.
With either communications option, the same data is available over the network. See Section 23, ‘
MPA
Communications Address Table ’ for accessible data.