MDR2
5-2-55, Minamitsumori, Nishinari-ku, Osaka 557-0063 JAPAN
Phone: +81(6)6659-8201 Fax: +81(6)6659-8510 E-mail: [email protected]
EM-8106 Rev.1 P. 3 / 3
TERMINAL CONNECTIONS
Connect the unit as in the diagram below.
Be sure to cross-wire between the ground terminal (G) and
that of the protected equipment.
TELEMETER
PLC
XMTR
M-RESTER
PROTECTED
EQUIPMENT
M-RESTER
P1
P2
P8
G
COM
RELAY
METAL
HOUSING
FIELD
S1
S2
S8
COM
S1
S2
S8
G
G
COM
P1
P2
P8
COM
■
GROUNDING
M-RESTER
PROTECTED
EQUIPMENT
G
G
CROSSOVER WIRE
GROUNDING
(100 ohms or less)
A crossover wire between M-RESTER ground and the ground or
metallic housing of the equipment is required for protection.
If the protected equipment has no ground terminal, ground the
M-RESTER only.
■
WIRING
PROTECT
SIDE
MONITOR
1
2
3
4
SURGE
SIDE
S1
S2
S3
S4
S5
P1
P2
P3
P4
P5
When the connections of serge and protecting sides get bun-
dled, the protection effect decreases. Be sure to wire them
separately.
Wiring to the terminals, please install wires according to
the above figure.
MAINTENANCE
Check M-RESTER periodically. Many cases of lightning are
ignored, and even lightning at a far distance often causes
inductive surges.
We recommend that you check your M-RESTER about twice
a year, before and after the rainy season. Check whenever
you experience a strong lightning occurrence.
Checking procedure is explained in the following:
■
CHECKING
WIRING
1) Make sure that wiring is done as instructed in the con-
nection diagram.
2) Make sure that the ground terminal (G) is connected to
the metallic housing of protected equipment.
3) Make sure that the ground terminal (G) is grounded to
earth.
DISCHARGE ELEMENTS
Approximate checking can be conducted as following.
• MDR2-8xA (with LED monitor)
1) Make sure that the front LED monitor turns OFF while
the discrete signal is ON.
2) When leakage current exceeds the rating (5μA), the LED
becomes brighter gradually. In this case, please replace
the unit.
3) When the discrete signal is unable to be ON, take the
same procedure as MDR2-8xN.
• MDR2-8xY (without LED monitor)
Remove all wiring connected to M-RESTER when you test
the discharge elements.
1) Check resistance across the following terminals on the
high resistance range of multimeter and confirm no con-
duction. (The meter will show 10MΩ or greater.)
Terminals (P1) or (P2) or (P3) or (P4) or (P5) or (P6)
or (P7) or (P8) – (COM), (COM) – (G)
When measuring across the Px to COM, apply the positive
voltage for MDR2-8N or negative voltage for MDR2-8P with
multimeter.
1) Check that discharging occurs across the same terminals
with a 500V DC/1000 MΩ insulation tester. (The tester
will show 20 MΩ or less.)
2) If any of the above tests shows negative, replace the
M-RESTER.
