Control Techniques Epsilon EP-P Reference Manual page 122

Figure 120:
Master
Slave
Figure 121:
a - Response Gap - Specifies the maximum timeout for the response packet. If a response packet is not detected within this
period then the slave device status is set to no_response.
b - Inter Character - Specifies the maximum period for receiving each character of the Modbus packet. If a character is not
received during this period, then the master considers the partial packet incomplete, and sets the slave device status to
no_response.
c - Inter Frame - Specifies the period of no data transmission indicating the end of the Modbus packet. Modbus specifications
generally specify this gap to be 3½ characters wide. If data is received during this period, then it is considered a part of the current
data packet.
d - Message Gap - Specifies idle period between the last packet received and the next packet transmitted. This gap allows for
extended quite time for multiple slaves on the same communications path; where slaves may be actively monitoring Modbus
packets and may miss the standard Inter Frame gap.
108
Modbus Master View - Slave Tab
∆a
Modbus RTU Timing Diagram
www.controltechniques.com
∆b ∆c ∆d
Epsilon EP-P Drive Reference Manual
Revision: A4