Emerson 848L Commissioning, Addressing, Hardware, Maintenance, Sensor Check, Communication/Power

Rosemount 848L

Reference Manual

000809-0100-4696, Rev AA September 2004

Commissioning	To be able to setup, configure, and have a device communicate with other
(Addressing)	devices on a segment, a device must be assigned a permanent address.
	Unless requested otherwise, it is assigned a temporary address when
	shipped from the factory.
	If there are two or more devices on a segment with the same address, the first
	device to start up will use the assigned address (ex. Address 20). Each of the
	other devices will be given one of the four available temporary addresses. If a
	temporary address is not available, the device will be unavailable until a
	temporary address becomes available.
	Use the host system documentation to commission a device and assign a
	permanent address.
HARDWARE	The 848L has no moving parts and requires a minimal amount of scheduled
MAINTENANCE	maintenance. If a malfunction is suspected, check for an external cause
	before performing the diagnostics presented below. The 848L has a green
	LED which indicates that the device has both DC I/O power and power from
	the bus. Once powered the green LED will remain illuminated as long as the
	I/O power is available even if bus power is lost.
	The red LED indicates that the Resource block is Out of Service. Any
	hardware fault detected except open or shorted sensors will place the
	Resource block in the Out of Service mode.
Sensor Check	The amber LEDs indicate if the 848L is detecting the sensor as open or
	closed. To check the input circuit you can connect a working sensor at the
	transmitter and check it's operation. Consult an Emerson Process
	Management representative for additional assistance.
	It is possible that the sensor LEDs do not reflect the actual state of a sensor
	since they are activated by the electronics and not directly by the sensor. Use
	appropriate electrical test equipment to verify actual sensor states.
Communication/Power	If the transmitter does not communicate or provides an erratic output, check
Check	for adequate voltage to the transmitter. The transmitter requires between 9.0
	and 32.0 VDC at the bus terminals to operate with complete functionality.
	Check for wire shorts, open circuits, and multiple grounds.

Resetting the Configuration (RESTART)

There are two types of restarts available in the Resource Block. The following section outlines the usage for each of these.

Restart Processor (cycling)

Performing a Restart Processor has the same effect as removing power from the device and reapplying power.

Restart with Defaults

Performing a Restart with Defaults resets the static parameters for all of the blocks to their initial state. This is commonly used to change the configuration and/or control strategy of the device, including any custom configurations done at the Rosemount factory.

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