beautypg.com

Rockwell Automation 57C428 Toledo Scale Interface Module User Manual

Page 18

background image

4Ć2

Registers 14 through 18 contain information on the number and

quality of messages received on the serial link. These counters will be

incremented only if the startĆofĆmessage character (STX) is

recognized by the module. Typically, these registers are used for

diagnosing the serial link when problems occur. Refer to figure 4.3.

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

bits

register 14

number of good messages received

not used

number of checksum or parity errors

number of overrun errors

number of framing errors

15

16

17

18

Figure 4.3Ć Receive Message Status

Register 20 is the configuration/update request register. The module

continually monitors this register, and will reĆconfigure the link

anytime the update flag is set. Refer to figure 4.4.

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

bits

register 20

- - - - - - - 0

update request

NonĆzero for update request

Figure 4.4 Ć Configuration/Update Request Register

Register 21 defines the serial port baud rate. The baud rate may be

1200, 2400, 4800, 9600 or 19,200. Refer to figure 4.5.
Register 22 defines the link inactive" timeĆout value to aid the user in

detecting link failures. Each time a startĆofĆmessage character (STX)

is received, a timer is initiated with this value. If the timer expires, the

next request by the application program for the scale data will result

in link inactive" status being returned. The timeĆout value is specified

in seconds with a minimum value of one and a maximum value of 10.

The default value is five. See figure 4.5.