ABB Relion 670 series, Technical Manual

Page: 1321 / 1432

22.2.11 mA input module (MIM)
IP14537-1 v1
22.2.11.1 Introduction
M15020-3 v4
The milli-ampere input module is used to interface transducer signals in the –20 to +20 mA range
from for example OLTC position, temperature or pressure transducers. The module has six
independent, galvanically separated channels.
22.2.11.2 Design
SEMOD55434-1 v1
M6380-3 v6
The Milliampere Input Module has six independent analog channels with separated protection,
filtering, reference, A/D-conversion and optical isolation for each input making them galvanically
isolated from each other and from the rest of the module.
For configuration of the input signals, refer to section "Signal matrix for mA inputs SMMI" .
The analog inputs measure DC current in the range of +/- 20 mA. The A/D converter has a digital
filter with selectable filter frequency. All inputs are calibrated separately The filter parameters and
the calibration factors are stored in a non-volatile memory on the module.
The MIM module can report measured values in two ways:
• Cyclic reporting
• Dead Band reporting
The parameter
MaxReportT defines the maximum time between two reports at cyclic reporting. If
MaxReportT is set to a value higher than 0 s, all the channels follow cyclic reporting disregarding
the settings EnDeadBandChx and DeadBandChx.
Deadband reporting requires that MaxReportT is set to 0, and EnDeadBandChx is set to On. The
DeadBandChx parameter defines the dead band range for channel x.
Table
1030: Parameter dependency
Reporting MaxReportT EnDeadBandChx DeadBandChx
Cyclic >0 Off yy
Cyclic >0 On yy
Deadband 0 On yy
The calibration circuitry monitors the module temperature and starts an automatical calibration
procedure if the temperature drift is outside the allowed range.
1MRK 502 066-UUS B Section 22
IED hardware
1315
Technical manual