Yokogawa EJX930A - Manual (Page 16)

<3. Parameter Setting>
3-6
IM 01C25R05-01EN
IMPORTANT
After setting and sending data with the
configuration tool, wait 30 seconds before
turning off the transmitter. If it is turned off
too soon, the settings will not be stored in the
transmitter.
3.2 Communication Setup
This section shows how to confirm and change
the EJX Multivariable Transmitter parameters for
Modbus communication. The setting is activated
after powering on except “Turnaround Delay Time”
and “Bus termination”.
• Procedure to call up the display
Item Procedure
Slave Address [Root Menu]
→ Communication setup
Stop Bit [Root Menu]
→ Communication setup
Parity [Root Menu]
→ Communication setup
Turnaround Delay
Time
[Root Menu]
→ Communication setup
Baud rate
[Hardware Switch]
Refer to 2.1.1 The Hardware
Switch
Bus termination
[Hardware Switch]
Refer to 2.1.1 The Hardware
Switch
(1) Slave Address
EJX Multivariable Transmitter slave address is
set by this parameter in order to identify the slave
device from the Modbus host. This parameter
should not be set as same address from multiple
devices under the multi drop connection. Address
can be selected from 1* to 247.
(2) Stop Bit
Select Modbus communication Stop Bit from 1bit*/
2bit
(3) Parity
Select Modbus communication Parity from none*/
even/odd
(4) Turnaround Delay Time
The waiting time (ms) between receiving the
request from the host and starting the response
from the device is set by this parameter. The actual
response time of the device is “communication
process time”() + “Turnaround Delay Time”().
When set to 10 ms* which is lower limit, the
response time is only “communication process
time”. Refer Figure 3.1.
*: Factory default setting.
NOTE
• We recommend that host timeout period is set
larger than 3 s when transmitted data size is
big.
• We recommend that the host communication
period() between receiving the response
from the device and sending the request to
the device is set larger than 100 ms under the
multi drop connection. Refer Figure 3.1.
REQUEST
1
Master
(Host)
Slave 1
Slave 2
RESPONSE
1
REQUEST
2
RESPONSE
2
  +  +
F0302.ai
Figure 3.1