Attributes to Configure in the Scan Device Point

Attribute Name Description
device address A user supplied RTU address (unit) number.
intercharacter TO The desired time to wait (in milliseconds) for the next byte from the RTU, before it is considered to be an intercharacter timeout as defined by the protocol (when this occurs any bytes already received will be discarded). If a value of zero is specified, a timeout value (in milliseconds) will be calculated using the following formula:

10 bits/char / baudrate bits/sec. * 3 char * 1000 msec/sec.

[note] This value is dependent upon the resolution of the system clock. Currently the system clock has a resolution of 20 milliseconds on the Series 300/400 and 10 milliseconds on the Series 800/700.

A minimum value of 1.5 x "system clock" will be used if a value of zero is specified. This should also be the minimum value entered in order for reliable messaging to occur.
prbx register Specifies the Modbus register to poll for in the RTU for the PRBX mask. If a value other than zero is returned, it will be used as a poll type mask (as specified in the scan input table). All records in the scan input table that match the mask returned and have the exception flag (see scan input table) field set, will be polled.
prbx reset register Specifies the Modbus register where the PRBX mask will be written to, after the PRBX has completed.
swap bytes

Specifies various swapping of words/bytes for 32-bit integers and floating point numbers. This attribute can be either an rtUINT8 or rtUINT16 data element type. If this attribute is an rtUINT8 data type, the same values will be used for both input and output. If this attribute is an rtUINT16 data type, the least significant byte will be used for input, and the most significant byte will be used for output. This attribute contains a bit mask. Multiple bits can be set to perform multiple swapping (in this case, the swapping order will occur from least significant bit to most). The possible bit values are:

Value Description
0 no word/byte swapping.
1 swap 32-bit float words.
2 swap 32-bit integer words.
4 swap 32-bit float's most significant word's bytes.
8 swap 32-bit integer's most significant word's bytes.
16 swap 32-bit float's least significant word's bytes.
32 swap 32-bit integer's least significant word's bytes.
64 swap all 32-bit float's bytes.
128 swap all 32-bit integer's bytes.
256 swap outgoing 32-bit float words.
512 swap outgoing 32-bit integer words.
1024 swap outgoing 32-bit float's most significant word's bytes.
2048 swap outgoing 32-bit integer's most significant word's bytes.
4096 swap outgoing 32-bit float's least significant word's bytes.
8192 swap outgoing 32-bit integer's least significant word's bytes.
16384 swap all outgoing 32-bit float's bytes.
32768 swap all outgoing 32-bit integer's bytes.
debug level A debug level used to determine the amount of information printed to the debug device. Higher debug levels print more detailed information. A debug level of zero indicates that no debug information is to be printed to the debug device.
clear stats Indicates whether the device stats vector will be zero'ed the next time it is read from the database.