Enter a descriptive name that eDrive will use to reference this device. Spaces and punctuation characters are allowed.
Device Type
From the drop down list, select the option: Modbus.
eDrive is only capable of direct communication with Modbus TCP devices. If the application calls for interface to Modbus RTU or Modbus ACII devices, it will be necessary to use a Modbus serial server device that will automatically convert to/from Modbus TCP.
Polling Timeout
From the drop down list, select the value (in seconds) that will determine how long eDrive will wait for responses from this device before declaring a timeout event and moving on to its next task.
The intent of the timeout period is to allow enough time for the device to fully respond to requests from eDrive, but also allow eDrive to move on to other tasks if the device is offline and not able to respond.
IP Address
Enter the IP Address of the Modbus TCP device. If the target Modbus device is on a serial (RTU) bus, enter the IP Address of the serial server or Modbus router that is being used to interface to the serial bus.
Port
Enter the IP Port Number used for this device. Default port for Modbus TCP communications is 502.
Target Interval
Enter the value (in seconds) that represents how often this device needs to poll all of its Point Objects. eDrive will distribute its polling activities over the Target Interval and attempt to complete the polling for all of its Point Objects within the Target Interval if possible.
Example: All selected points for this device only need to be updated once every 2 minutes. Set the Target Interval to 120 seconds.
When practical, use a longer value of Target Interval to spread out the polling activities and minimize impact on network bandwidth.
Pacing
For Modbus TCP devices, eDrive is capable of multi-threaded polling to improve throughput. Pacing sets the amount of time eDrive will wait before launching an additional polling thread for the same device.
If the device responds to requests quickly, before the Pacing interval is reached, no additional threads are needed.
If responses from the device take longer than the Pacing interval, eDrive will launch an additional thread to poll for point values. (see Maximum Polling Threads parameter below.)
Maximum Polling Threads
Many Modbus TCP devices utilize a TCP stack designed to handle multiple requests in a queue for sequential processing. Performance gains are possible by allowing eDrive to send point value requests on multiple threads and utilize the device's TCP stack.
Maximum Polling Threads value can be set from 1 to 8. A value of 1 will limit eDrive to use only a single thread and poll for all Point Objects sequentially. Higher values will allow eDrive to maximize throughput to the device if it is capable.
Device Address
For Modbus RTU devices utilizing a Modbus router or serial server network interface, enter the address of the device on the serial bus.
For Modbus TCP devices, this value will usually be set to 1.
Modbus Point Object Configuration Parameters:
Name
Enter a descriptive name that eDrive will use to reference this Point Object. Spaces and punctuation characters are allowed.
If '/' (forward slash) characters are included in the name, eDrive will create the Point Object in a hierarchical, tree structure with the '/' characters as delimiters. The tree structure will appear in the list of eDrive objects along the right hand side of the page.
Function Code
From the drop down list, enter the Modbus Function Code used to poll for this object. Common Modbus Function Codes are:
Enter the (integer) value of the Modbus register number for this point.
Register numbers are considered 'absolute' or 'zero referenced' values. The target device register list values may require that you compensate for legacy-compatible addresses. For example, registers shown as 40001 - 40010 may need to be entered in eDrive as addresses 0 - 9.
Register Type
From the drop down list, select the type that corresponds to the manner in which the values are presented by the device.
For 32-bit and 64-bit registers, eDrive assumes that the response values are presented in sequence of high-order bytes first, low-order bytes last. Some Modbus devices however present values with their low-order bytes first. In these cases, select the option from the list with the 'swapped' designation.
Bit Mask
Often 16-bit and 32-bit registers are used to hold the values of several binary values within the device. Individual binary values are 'packed together' into a single register.
If needed, the Bit Mask value can be used to 'unpack' the register's value and isolate a single bit that represents the selected Point Object value.
Block
Check this box to designate that this register should force the start of a new block of register addresses.
eDrive will automatically examine the register addresses for the Point Objects you have entered. Where possible, it will group neighboring registers together into a single, read-range-of-registers request. This automatic collection of registers greatly increases the throughput of point values.
But under certain conditions the automatic collection of registers spans an address that causes the device to give an error response or no response at all. In these cases it becomes necessary to instruct eDrive to break up its read-range-of-registers requests at each register marked with the Block option checked. This way eDrive avoids requesting intermediate registers that would result in error responses.
Note! You can assign Additional Properties to any Point Object such as Offset, scaling Multiplier, History, etc. Please refer to the Additional Point Properties section for more detail.
When Device and/or Point Object configuration is complete, select the Submit Config function to save your changes to eDrive.
