MDP-PA
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-8207 Rev.3 P. 3 / 3
TERMINAL CONNECTION
Connect the unit as in the diagram below.
Be sure to cross-wire between the Ground terminal (G) and that of the protected equipment. When the surge protector is con-
nected with a device which has no ground terminal such like M-System’s (See figure below), ground the M-RESTER Ground
terminal (G) only.
Protected Device
MDP-PA
G
1
3
A
C
2
SHLD
G
+
–
B
PA
BUS
Grounding
≤100
Ω
Cross wiring
*
2
*
1
*
1. Cross wire to the surge protector’s G terminal when grounding the shield wire.
If the shield wire is not to be grounded, connect it to B terminal.
*
2. Follow instructions provided with the protected device whether 2 terminal
should be connected or not. However, if the shield terminal of the protected
device is not isolated from PA BUS, DO NOT connect 2 terminal to the
protected device.
Protected
Devices
(Nodes)
MDP-PA
G
G
G
G
MDP-PA
G
G
G
Protected
Devices
(Nodes)
When the distance between nodes are relatively long (e.g. grouped and separated by cabinets),
install the MDP-PA by each group of devices. Insert the MDP-PA at the surge side of the network.
For detailed information on the network, refer to that provided by PROFIBUS International or
Fieldbus Foundation.
*
1. Fieldbus devices complying with IEC 61158-2 operate by a supply voltage between
9V and 32V DC.
Take the MDP-PA’s internal series resistance into consideration when determining the
cable distance if there is a large current flow on the bus line.
Crossover Wire
Crossover Wire
*
1
■
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.
When the M-RESTER is mounted with DIN Rail Mounting Adapter,
connect the grounding wire to the mounting screw of the M-RESTER.
WIRING INSTRUCTIONS
■
SCREW TERMINAL
Torque: 0.8 N·m
MAINTENANCE
Check surge protectors periodically. Many cases of light-
ning are ignored, and even lightning at a far distance often
causes inductive surges.
We recommend that you check your surge protector 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 FUNCTION
The M-RESTER Tester is available for a preliminary check-
ing of the surge protector’s head element.
Approximate testing procedure without using the Tester is
explained as below.
1) Remove all wiring connected to the surge protector when
you test the element module.
2) Check resistance across the following terminals on the
high resistance range of multimeter and confirm no con-
duction. The meter shows ≥10MΩ.
Terminals (A) – (G), (B) – (G), (C) – (G)
3) Check that discharging occurs across the same terminals
with a 500V DC 1000MΩ insulation tester (The tester
shows ≤ 20MΩ).
If any of the above tests shows negative, replace the pro-
tector.
