Emerson 848T manual Multiple Analog Input MAI Function Block

Reference Manual

00809-0100-4697, Rev EA October 2011

Rosemount 848T

MULTIPLE ANALOG INPUT (MAI) FUNCTION BLOCK

	OUT_1
	OUT_2
MAI	OUT_3
	OUT_4
	OUT_5
	OUT_6
	OUT_7
	OUT_8

The Multiple Analog Input (MAI) function block has the ability to process up to eight field device measurements and make them available to other function blocks. The output values from the MAI block are in engineering units and contain a status indicating the quality of the measurement. The measuring device may have several measurements or derived values available in different channels. Use the channel numbers to define the variables that the MAI block processes.

The MAI block supports signal scaling, signal filtering, signal status calculation, mode control, and simulation. In Automatic mode, the block’s output parameters (OUT_1 to OUT_8) reflects the process variable (PV) values and status. In Manual mode, OUT may be set manually. The Manual mode is reflected on the output status. Table D-4lists the MAI block parameters and their units of measure, descriptions, and index numbers. The block execution time is 30 ms.

Out1 = The block output value and status for the first channel.

Table D-4. Multiple Analog Input Function Block Parameters

Number	Parameter	Units	Description
1	ST_REV	None	The revision level of the static data associated with the input selector block. The
			revision value will be incremented each time a static parameter value in the block is
			changed.
2	TAG_DESC	None	The user description of the intended application of the block.
3	STRATEGY	None	The strategy field can be used to identify grouping of blocks. This data is not
			checked or processed by the block.
4	ALERT_KEY	None	The identification number of the plant unit. This information may be used in the host
			for sorting alarms, etc.
5	MODE_BLK	None	The actual, target, permitted, and normal modes of the block.
			Actual: The mode the “block is currently in”
			Target: The mode to “go to”
			Permitted: Allowed modes that target may take on
			Normal: Most common mode for target
6	BLOCK_ERR	None	This parameter reflects the error status associated with the hardware or software
			components associated with a block. It is a bit string, so that multiple errors may be
			shown.
7	CHANNEL	None	Allows for custom channel setting. Valid values include:
			0: Unitialized
			1: Channels 1 to 8 (index values 27 to 34 can only be set to their corresponding
			channel number, i.e. CHANNEL_X=X)
			2: Custom settings (index values 27 to 34 can be configured for any valid channel
			as defined by the DD)
8, 9, 10, 11,	OUT (1, 2, 3, 4, 5,	EU of OUT_SCALE	The block output value and status
12, 13, 14,	6, 7, 8)
15
16	UPDATE_EVT	None	This alert is generated by any change to the static data
17	BLOCK_ALM	None	The block alarm is used for all configuration, hardware connection feature, or
			system problems in the block. The cause of the alert is entered in the subcode field.
			The first alert to become active will set the Active status in the Status parameter. As
			soon as the Unreported status is cleared by the alert reporting task, another block
			may be reported without clearing the Active status, if the subcode has changed.
18	SIMULATE	None	A group of data that contains the current sensor transducer value and status, and
			the enable/disable bit.

D-9