Cirrus Logic CS485 Spécifications télécharger pdf (Page 32)

C E N T A U R U S P R I M E

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Click Transfer > Receive File: Enter the location to save the file and make sure that

Xmodem is selected and then click the Receive button. The next dialog box will ask

you to specify a filename and when you click “OK” the file will be received from the

Gateway.

Setting up the Modbus Driver

After the Gateway is ready to go and you have your database configured, one of the

last steps is to make sure that you have the Modbus driver settings for the

Host/Master setup correctly. The following information should be kept in mind when

configuring the driver

Modbus commands that are accepted by the Gateway are:

1 - Read Coils (0000's)

2 - Read Discretes (10000's)

3 - Read Holding Registers (40000's)

4 - Read Input Registers (30000's)

5 - Force Single Coil

6 - Preset Single Register

7 - Read Exception Status (Status is 0 if OK; o/w internal error-code)

15 - Force Multiple Coils

16 - Preset Multiple Registers

17 - Report Slave ID (Emulates Modicon Micro-84)

Most Modbus drivers have many setup options and each vendor is different. Following

are some limits with the Modbus Gateway that you need to consider when setting up

your driver.

MAXIMUM number of coils read at once (CMD #1) is 64

MAXIMUM number of discretes read at once (CMD #2) is 64

MAXIMUM number of holding registers read at once (CMD #3) is 32

MAXIMUM number of input registers read at once (CMD #4) is 32

MAXIMUM number of coils forced at once (CMD #15) is 8

MAXIMUM number of registers preset at once (CMD #16) is 8

TIMEOUT for a command should be a minimum of 350 milliseconds

(500 ms recommended)

TIME BETWEEN commands should be a minimum of 50 milliseconds

(100 ms recommended)

NUMBER OF TIMEOUTS before "slow polling" should be a minimum of

3 (3 recommended)

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Cirrus Logic CS485 Spécifications Page 32