Emerson E2 operation manual 8RO, 8ROe, 8IO, and MultiFlex Outputs, Set

NO_BYP for inputs that initiate bypasses) will make the input’s state easier to read and understand.

To choose an engineering unit, press  (LOOK UP) to select.

Push Button Mode? Digital inputs may be set up as “push button” inputs by changing this field to “YES”.

Push Button Mode is a method of interpreting a digi- tal state that is used strictly for push buttons. When used, a button press lasting longer than one second will change the state of the input. In other words, if the input is OFF, a button press will change it to ON, and another button press will change it back to OFF, etc.

Output This field displays the link between the input and its application(s). You do not need to enter any- thing in this field. You will be able to link applica- tions to this point during the application setup process.

9.2The 8RO, 8ROe, 8IO, and MultiFlex Outputs

The 8RO, 8ROe, 8IO, and MultiFlex have relay out- puts that close when called to be ON and open when called to be OFF. When an output point is closed (ON), the LED directly above the output terminal glows red. These boards use Form C contacts that determine if the connection will be open or closed during power failure. A fail-safe dip switch is used to determine connection status during net- work failure.

9.2.1Wiring Form C Contacts

Figure 9-8shows how to wire the three-terminal Form C contact.

One wire of the two-wire connection should always be connected to the middle terminal. The second wire must be connected to the N.C. terminal (if you want the relay to be closed (ON) during power failure) or the N.O. terminal (if you want the relay to be (OFF) during power failure).

RELAY IS	RELAY IS
CLOSED	OPEN ON
ON POWER	POWER
FAILURE N.C.	N.O. FAILURE N.C.	N.O.

Figure 9-8- Form C Contact Wiring

9.2.2MultiFlex Relay Outputs

The MultiFlex boards that have relay outputs (all mod- els except the MultiFlex 16) each have eight relays that energize and de-energize to control output loads.

When setting up an output on one of these relays, you must make two important decisions:

1.Do you want an ON command from your control- ler to mean “energize the relay” or “de-energize the relay,” and

2.When the relay is de-energized, as is the case when the 8RO or 8IO goes off-line or loses power, do you want the contacts to be OPEN or

CLOSED?

Decision #1 is made by setting the fail-safe switch. This is a bank of eight switches labeled S2 on the 8RO, 8ROe, and 8RO-FC, S3 on the 8IO, and S1 on the Multi- Flex plug-in output board. Each switch corresponds to an output on the board (switch #1 = output #1, etc.).

Decision #2 is made either by setting a fail-safe jumper (for old-style 8ROs) or by wiring the load to either the N.O. or N.C. terminals on the Form C contact (all other output boards).

Table 9-3shows how the fail-safe switch, jumpers, and/or Form C contacts should be configured based on how you want the output to perform during both normal operation and during network/power loss.

			Set
Controller		Set	Jumper or
	Fail		Wire Form
Command vs.		Switch
	State		C
Contact State		To:
			Contacts
			To:
ON=CLOSED	ON	UP	N.C.
OFF=OPEN
ON=CLOSED	OFF	UP	N.O.
OFF=OPEN
ON=OPEN	ON	DOWN	N.O.
OFF=CLOSED
ON=OPEN	OFF	DOWN	N.C.
OFF=CLOSED

Table 9-3- Output Board Fail-Safe and Switch Settings

9.2.3Setting the Fail-Safe Dip

Switch

The fail-safe dip switch determines the sate of the relay when communication is lost between the board and E2.

9-10 • E2 RX/BX/CX I&O Manual 026-1610 Rev 13 14-SEP-2011