Meggitt VM600 Hardware Manual

VM600 MPS hardware manual (standard version) MAMPS-HW/E 9 - 31
Edition 17 - February 2018
Configuring the four local relays on the IOC4T
CONFIGURATION OF MPC4 / IOC4T CARDS
As explained in 9.4.2 Operation of relays, jumpers must be set on the IOC4T card to
configure each relay as normally energised (NE) or normally de-energised (NDE), and as
normally open (NO) or normally closed (NC).
Table 9-5 shows the required jumper settings for IOC4T cards. See Figure 9-23 for an
electrical diagram showing the jumpers and Figure 9-24 for the position of the jumpers on the
IOC4T card.
9.4.1 Relay terminology
By convention, the normally closed (NC) and normally open (NO) relay terminology refers to
the state of the relay contacts when the relay’s coil is de-energised. This use of the word
“normally” is not directly related to the “normal” operation/state of the machinery being
monitored, as explained below.
When the power supply to a device is turned off:
• There is a closed circuit between the normally closed (NC) and common (COM) contacts.
• There is an open circuit between the normally open (NO) and common (COM) contacts.
When the power supply to a device is turned on, the state of the relay contacts depends on
whether the relay’s coil is energised or de-energised.
When the relay’s coil is energised:
• There is an open circuit between the normally closed (NC) and common (COM) contacts.
• There is a closed circuit between the normally open (NO) and common (COM) contacts.
Whether a relay’s coil is energised or de-energised depends on how the relay has been
configured, for example, as normally de-energised (NDE) or normally energised (NE) and as
latched or not latched. It also depends on the control signal that is used to drive the relay. For
example, specific alarms (A+, D and so on) generated by an MPC4 card (see Table 9-4).
9.4.2 Operation of relays
A relay can be configured to be either normally de-energised (NDE) or normally energised
(NE).
Table 9-5: Jumper settings to configure relays as NE/NDE and NO/NC
Normal state of
control signal
Jumper
J100x
Jumper
J70x
Relay
coil
Relay
contact
1 1-2 1-2 NDE NO
1 1-2 1-3 NDE NC
11-31-2NENC
11-31-3NENO
01-21-2NENC
01-21-3NENO
0 1-3 1-2 NDE NO
0 1-3 1-3 NDE NC

Meggitt VM600 Specifications

General

Brand	Meggitt
Model	VM600
Category	Measuring Instruments
Language	English