Application linked Modbus Parameters

At a Glance

After configuring the communication channel, you need to enter the application parameters.

These are split into four windows:

Type window
Master window
Slave window
Current loop (PSR) window

Type Parameter

This window looks like this:

It enables you to select the type of Modbus Protocol the module uses:

Master: selects Modbus Master where the station is master
Slave: selects Modbus Slave where the station is slave
Immediate server: allows UNI-TE requests to be directed to the SERVER function and not to the processor's main server

NOTE: The Immediate server parameter requires the communication function to be programmed in Control Expert.

It is valid until the box is checked.

Master Function

This window is only accessible by selecting Master:

This allows you to enter:

the Number of retries:

number of connection attempts made by the master before defining the slave as absent
- Default value is 3.
- Possible values are between 0 and 15.
- Value 0 indicates no retries by the Master.
the Answer delay:

Time elapsed between the request made by the Master and a repeat attempt if the slave does not respond. It corresponds with the maximum time between the transmission of the last character of the Master.'s request and receipt of the first character of the request sent back by the slave.
- The default value is 1s (100*10ms).
- Possible values are between 10ms and 10s.

When sending a Broadcast EF, following EF requests will be delayed depending on the Answer delay value (after a broadcast, the Modbus master will wait for the Answer delay to be elapsed before sending other requests).This feature is available on following modules:

SCY21601 from firmware version 2.8 ie41
SCY11601 from firmware version 1.2 ie06
SCP111 from firmware version 3.2 ir21
SCP114 from firmware version 3.2 ir21
SCP1114 from firmware version 3.2 ir21

NOTE: The Answer delay of the Master must be at least equal to the longest Answer delay of the Slaves present on the bus.

Slave Function

This window is only accessible by selecting Slave:

This allows you to fill in the Slave number of the device:

TSX SCY 21601:
- The default value is 98.
- Possible values lie between 1 and 98.
TSX SCY 11601:
- The default value is 247.
- Possible values lie between 1 and 247.

CAUTION

UNEXPECTED BEHAVIOR OF APPLICATION

Do not use wrong address parameters. For instance:

Do not set an address parameter that does not correspond to the targeted equipment.
Do not use value higher than 98 in ADDR function (field "e" for the equipment address) when using CPU embedded serial port or TSXSCY21601 channel 0 or 1.

Failure to follow these instructions can result in injury or equipment damage.

Current Loop Function

This window looks like this:

It allows you to select a:

Multidrop (Current Loop) communication
Point to point (Current Loop) communication