RelayDoc User Manual
Page 15
Version 1.25
Filename: RelayDoc User Manual v1.25.docx
© MRD Rail Technologies Pty Ltd
14Sep2017
COMMERCIAL IN CONFIDENCE ©2016 MRD RAIL TECHNOLOGIES PTY LTD WWW.MRD.COM.AU +61 7 3821 5151
7.
T
EST
F
UNCTIONALITY
C
OIL
R
ESISTANCE
The Coil Resistance Test passes a precise constant current through
the coil. The voltage drop across the coil is measured and the coil
resistance is calculated. The result is recorded.
The coil resistance measurement uses two different scales to
generate high precision results.
Scale
Current
Range
Precision
1
10mA
0 – 500
Ω
1
Ω
2
1mA
500 – 10 k
Ω
1
Ω
C
ONTACT
R
ESISTANCE
The contact resistance test passes a precise constant current through each contact. The voltage drop across
each contact is measured and the contact resistance is calculated. Accurate results are the result of using a
Four Wire Kelvin measurement method up to the Test Base contact. This eliminates any resistance error from
cables or connections between the RelayDoc and the EUT.
The RelayDoc manages the Contact Resistance Measurement,
automatically increasing the applied current in stages until the
measured resistance is in one of the ranges shown right.
Measured resistance over 500
Ω
is defined to be OPEN state.
C
ONTACT
C
ONDITIONING
Contact Conditioning is a flash cleaning method. In the RelayDoc
implementation, a Constant Current Source (CCS) provides 100mA as
the relay contacts. There is a short current surge as the contact
opens or closes and the resulting plasma arc cleans the contact
surface.
RelayDoc prevents Contact Conditioning being included in any
default Test Process. If EUT fails an initial resistance test, RelayDoc
will ask the operator to authorise Contact Cleaning and re-test of any failed relays, prior to creating the Test
Report. Only Relays that fail the initial test will be conditioned and re-tested.
The Operator may select Contact Conditioning to be included in the current Test Process, in which case the
software will not offer conditioning following a Resistance Test failure.
C
ONTACT
S
WITCHING
T
IME
This test is performed by measuring the time it takes for a relay contact to change state from Open to Close or
vice versa. Open and Close values are factory set. Users cannot adjust the settings.
O
PERATING
V
OLTAGE AND
C
URRENT
The Relay Operate voltage is measured using a Ramp Method: The coil supply voltage is swept from zero up to
nominal rated voltage, while monitoring from an open to closed contact state.
The ramp parameters are factory set and cannot be changed by the user.
Stage Current
Range
Precision
1
100mA
0-5
Ω
0.001
Ω
2
10mA
5-50
Ω
0.01
Ω
3
1mA
50-500
Ω
0.1
Ω