Cooper Bussmann Wireless Ethernet & Device Server
Three “Modbus TCP Client Mappings” are also configured at B in order to perform the required I/O transfer. The first mapping transfers the status of the onboard digital input at C to the onboard digital output at B. Local Register 4320 specifies the register for the onboard digital output at B (since B is the local unit at which the mapping is configured). I/O Count 1 specifies that only one I/O point is being transferred (i.e., the single digital I/O). Function Code 02: Read Discretes specifies the standard Modbus function code to read discrete (i.e., digital) inputs. Destination Register 4300 specifies the register for the onboard digital input at unit C (since C is the destination unit for this mapping). Device ID 1is the ID of the onboard Modbus TCP Server at C. Server IP Address 192.168.0.200 is the IP address of unit C – which is the Modbus TCP Server we are reading from. Response Timeout 1000 ms specifies that unit C must respond to this message within 1000ms. Comm Fail Register 0 specifies the local register where the communications status for this mapping will be stored.
The second mapping reads 8 registers from serial unit D into onboard registers in unit B. Note that in this case the specified Device ID 6 is the Modbus Address of the serial device D, while the Server IP Address 192.168.0.200 is the IP Address of unit C since the Modbus TCP to RTU Gateway at unit C converts the Modbus TCP message to Modbus RTU and routes it out the serial port to unit D.
The third mapping takes the 8 registers read by the second mapping and writes them to the serial unit A. The specified Device ID 5 is the Modbus Address of the serial device A, and the Server IP Address 192.168.0.196 is the IP Address of the local unit B since the local Modbus TCP to RTU Gateway is to route the message out the serial port to unit A.
Since the
Modbus TCP Configuration on I/O Transfer Menu:
Enable Modbus TCP Server (Slave) | Check this box to enable the onboard Modbus TCP Server. All Modbus TCP connections to the |
| module IP Address and specified Modbus Server Device ID will be routed to the onboard I/O |
| registers. |
Modbus Server Device ID | Specify the Modbus Device ID for the onboard Modbus TCP Server. Allowed values are 0 to 255. |
Enable Modbus TCP Client (Master) | Check this box to enable the onboard Modbus TCP Client. I/O to be transferred via the Modbus TCP |
| client is specified with Modbus TCP Client Mappings. |
Modbus Client Scan Rate | Enter the delay (in milliseconds) between execution of consecutive Modbus TCP Client Mappings |
| to the same Server. |
Reset Registers on Comm’s Fail | When Enabled the value in any onboard I/O register will be reset to zero if a valid Modbus |
| transaction directed to/from the given register has not been completed for longer than the |
| Comms Fail Timeout. |
Comms Fail Timeout | The period of time after which onboard I/O registers will be reset if a valid Modbus transaction |
| directed at that register has not completed. |
Enable Modbus Statistics | Enables the Modbus Diagnostic registers as shown in Section 4.4 “Internal Diagnostic Modbus |
| Registers” Disabling this option will free up the registers and also slightly increase processing |
| resources. |
Log background Noise | RSSI & BGND on Rx messages are made available in the diagnostic registers (See 4.4 “Internal |
| Diagnostic Modbus Registers” for details. For a Hex value of 5F5D the 5D byte = RSSI and the |
| 5F byte = BGND (Convert value from hex to dec and add a |
| option removes the RSSI byte from these registers and so only the Background Noise value is |
| made available. |
3A1582Rev1.6 | www.cooperbussmann.com/BussmannWirelessResources | 51 |
