lcaPut

Calling Sequence

lcaPut(pvs, value, type)

Description

Write to a number of PVs which may be scalars or arrays of different dimensions. It is possible to write the same value to a collection of PVs.

Parameters

pvs

Column vector (in matlab: m x 1 cell- matrix) of m strings.

value

m x n matrix or 1 x n row vector of values to be written to the PVs. If there is only a single row in value it is written to all m PVs. value may be a matrix of “double” precision numbers or a (matlab: cell-) matrix of strings (in which case the values are transferred as strings and converted by the CA server to the native type — this is particularly useful for DBF_ENUM / “menu” type PVs).

It is possible to write less than n elements — labCA scans all rows for NaN values and only transfers up to the last non-NaN element in each row.

type

(optional argument) A string specifying the data type to be used for the channel access data transfer. Note that labCA always converts numerical data from “double” locally.

It can be desirable, to use a different data type for the transfer because by default CA transfers are limited to ˜ 16kB. Legal values for type are byte, short, long, float, double, char or native. There should rarely be a need for using anything other than native, the default, which directs CA to use the same type for transfer as the data are stored on the server. If value is a string matrix, type is automatically set to char.

Note that while native might result in different types being used for different PVs, it is currently not possible to explicitly request different types for individual PVs (i.e. type cannot be a vector).

Examples

// write a PV
    lcaPut( 'thepv', 1.234 )
// write as a string (server converts)
    lcaPut( 'thepv', '1.234' )
// write/transfer as a short integer (server converts)
    lcaPut( 'thepv', 12, 'short' )
// write multiple PVs (use { } on matlab)
    lcaPut( [ 'pvA'; 'pvB' ], [ 'a'; 'b' ] );
// write array PV
    lcaPut( 'thepv' , [ 1, 2, 3, 4 ] )
// write same value to a group of PVs (string
// concatenation differs on matlab)
    lcaPut( [ 'pvA'; 'pvB' ] + '.SCAN', '1 second' )
// write array and scalar PV (using NaN as a delimiter)
    tab = [ 1, 2, 3, 4 ;   5, %nan, 0, 0 ]
	lcaPut( [ 'arrayPV'; 'scalarPV' ], tab )