User Manual

Compact IO™ Isolated HART Analog Input Module
U ser 's M a n u a l 0 300 21 5- 03 R ev. A
7-12
Words 4…23 (Message Request Buffer)
The message request buffer contains the data being sent to the module for the current
page (up to 38 bytes).
7.3.2 Module Input Tags Used For Messaging
The module utilizes 22 input words to receive messages and control data flow. The table
belo w shows the inp ut words used b y the module. Refer to Chapter 6 for more
infor mati on regarding input wo rds 0 through 27.
Table 7-7 (Module Input Table)
Word/Bit
¹
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
1
2
3
4
5 OS3OS2OS1OS0 S3S2S1S0
6 L3H3U3O3L2H2U2O2L1H1U1O1L0H0U0O0
7
8..27
28
29
30..49
50..71
(1) Changing bit values is not s upported by a ll controllers. R efer to you r controller manual for det ails.
Reserved
Time Stamp Value
Message Response Size
Not Used
Pad (16 bit alignment)
Message Response Buffer
Analog Input Data Channel 0
Analog Input Data Channel 1
Analog Input Data Channel 2
Analog Input Data Channel 3
HART Packet Data
Message Slave Control
Word 28 (Message Slave Control)
Again, the message slave control is used with the message master control to mana ge
which pages are being sent and what di rection the pa ge is goi ng, that i s , whether the page
is being sent to the module or r ead from the module. Refer to Figure 7-5 for the la yout.
The message slave control is also used to indicate if a message was rejected by the
module. If a message is rejected , the lower 8 bits will be set ( i.e. FF Hex) in the message
slave control. In the event the message is rejected, the message response buffer will
display a fault code in the first byte followed by a checksum in the second. The table
below lists the possible responses:
Table 7-8 (Paging Error Codes)
Error Code Description
1 A page was sent out of sequence.
2
While processing page 2,3,etc. The message size was different than it
was for page 1.
3 The message size given exceeds the max allowed.
4 The message page data checksum is not correct.
Word 29 (Message Response Size)
The message response size indicates the total number of bytes being returned by the
module.