The data path is NS5-SQ10-V2 Port B → 9-pin RS-232 → NS-Al002 converter → RS-485 → Yaskawa V1000. The HMI sends each request; the drive replies as the addressed Modbus slave. Port A remains assigned to the PLC. Start at the electrical layer, then configure the protocol and register map.
Where does the communication path stop?
Port B and the drive do not expose the same electrical interface. RS-232 is a point-to-point, single-ended interface, while RS-485 uses a differential pair and supports addressed devices. A cable that only rearranges connector pins cannot translate between them. For this installation, the NS-Al002 performs the RS-232-to-RS-485 conversion.
| Path segment | Interface | Configuration responsibility | Failure indication |
|---|---|---|---|
| HMI to converter | Port B, 9-pin RS-232 | Correct connector and converter assignment | No request reaches the RS-485 side |
| Converter to drive | RS-485 | Polarity, conductor count, reference conductor if required, and termination | Requests appear, but the drive cannot decode them |
| Serial framing | Modbus RTU | Matching baud rate, parity, data bits, and stop bits | Frames arrive with errors or receive no reply |
| Application request | Drive register protocol | Slave address, operation, starting address, and quantity | Exception response, wrong value, or rejected write |
Inspect the terminal labels and wiring diagrams for both the converter and drive before connecting the RS-485 side. Determine whether each device expects two-wire or four-wire operation; the model names alone do not settle that detail. Keep the pair polarity consistent, terminate only at the physical ends when termination is required, and avoid star branches. Protocol changes cannot correct reversed conductors or an incompatible two-wire/four-wire arrangement.
Which NS communication approach fits the drive?
The deciding factor is the protocol implemented by the selected NS Host Type, not the fact that the target is an inverter. A device-specific host driver and a generic Modbus RTU host can both use serial wiring, but they do not necessarily generate the same request format or expose addresses in the same way.
| Approach | Use it when | Register entry | Main limitation |
|---|---|---|---|
varispeed / VS mini Host Type |
The NS compatibility information explicitly lists the exact Yaskawa drive family | The NS driver may present its own device and address notation | It is not a universal inverter setting |
| Generic Modbus RTU host | The NS project software provides the option and the target drive documents Modbus RTU slave operation | Map the drive's documented slave address, operation, starting address, and quantity | Each drive brand retains its own register map and write rules |
For the V1000, first check whether the exact model is listed for the NS varispeed / VS mini driver. Use that driver only when the compatibility information covers it. Otherwise select the generic Modbus RTU method supported by the NS software and build addresses from the V1000 communication manual.
For an INVT CHF100A or Mitsubishi FR700, repeat the compatibility check from the beginning. Do not retain varispeed / VS mini merely because the new target is also a drive.
Why is the Host Type not universal?
Modbus RTU defines how a request identifies a slave, operation, starting address, and quantity. It does not standardize which register starts the motor, which register reports frequency, how a setpoint is scaled, or which writes require communication control to be enabled. Those meanings belong to the drive's register map.
| NS field | Meaning | Where to obtain it |
|---|---|---|
| Slave Address | The station number assigned to the target drive | Drive communication parameter and NS host configuration |
| Function Code or operation | The requested read or write operation | Drive register table and the selected NS driver documentation |
| Starting Modbus Address | The first drive register in the transaction | Drive communication register table |
| Number | The count of contiguous registers or elements transferred | The HMI object data width and the drive table |
A driver may hide the numeric Modbus function code and expose a symbolic memory area instead. In that case, enter the address in the driver's notation rather than copying a raw Modbus number into an unrelated field. Also compare address-base conventions: some documentation displays human-readable register numbers while software expects a protocol offset. Resolve the convention from the two manuals and test one known read before creating a large map.
How do you configure Port B and the drive?
- Leave Port A assigned to the PLC and select Port B for the drive connection in the
NS5-SQ10-V2project. - Select the Host Type using the compatibility decision above. Confirm that the selected entry describes either the exact Yaskawa family or generic Modbus RTU.
- Install the
NS-Al002between the Port B 9-pin RS-232 connection and the drive's RS-485 terminals. - Wire the RS-485 conductors from the terminal designations in both product manuals. Match polarity and the required two-wire or four-wire topology.
- Set identical serial framing at both ends: baud rate, parity, data bits, and stop bits. Read the actual drive parameters rather than relying on defaults.
- Assign the drive slave address and enter the same address in the NS host definition. Each slave on a multidrop network must have a unique address.
- Set communication control in the drive where required by its manual. Reading status and accepting run or reference writes can be governed by different drive settings.
- Download the HMI project, then restart or reinitialize communication if the selected products require new serial settings to take effect.
Do not tune timeouts to conceal a dead physical link. Establish valid request and response frames first. After replies are stable, set the HMI response timeout and retry behavior to accommodate the configured serial rate and the drive's documented response behavior. Excessive retries make failed devices slow the entire polling cycle.
How do you create a safe register map?
- Choose one documented, read-only status register whose value can be checked at the drive keypad or another local indication.
- Identify its data type, width, signedness, byte or word order, and scaling from the drive register table.
- Create one NS numeric display for that register. Use a quantity that matches the documented data width.
- Test the read and compare the raw value before adding engineering-unit scaling in the HMI.
- Add adjacent status values only after confirming whether the addresses are contiguous and readable in one transaction.
- Add writes last. Confirm the register is writable, the value range is valid, and the drive is configured to accept commands from communications.
A correct reply can still produce an incorrect display when the HMI interprets a multi-register value in the wrong word order or applies the wrong scale. A rejected write can likewise indicate a read-only register, an out-of-range command, or a drive control-source setting rather than a broken network.
How do you verify each hop?
| Observation | Likely boundary | Next check |
|---|---|---|
| No transmitted requests | NS project or Port B assignment | Confirm host selection, enabled polling object, and downloaded project |
| Requests leave the converter but no reply returns | RS-485 wiring, framing, or slave address | Check polarity, topology, serial settings, and the drive's configured address |
| Drive returns an exception | Application request | Check operation, starting address, quantity, and access rights |
| Read succeeds but write fails | Register permissions or drive command source | Check writable range and communication-control parameters |
| Value is stable but wrong | Data interpretation | Check address base, width, signedness, word order, and scaling |
Follow one transaction from the NS request through the converter to the drive response. Begin with a read-only register, change a locally observable condition, and confirm that the displayed raw value changes as documented. Perform motion-related write testing only with the machine placed in an approved test state.
FAQ
How do I connect an Omron NS5 RS-232 port to a V1000 RS-485 port?
Use Port B through the NS-Al002 RS-232-to-RS-485 converter, then wire the converter to the drive using the terminal designations and topology specified by both manuals.
How do I find the Modbus starting address for a V1000?
Read it from the V1000 communication register table, then translate it using the address convention required by the selected NS Host Type. Validate the result with one documented read-only status register.
How do I use the NS with a CHF100A or FR700?
Select a host driver that explicitly supports the exact drive, or use a generic Modbus RTU option documented for the NS. Build a new map from the CHF100A or FR700 manual; varispeed / VS mini is not a universal inverter driver.
How do I verify that NS-to-drive communication is working?
Read one known status register, compare its raw value with the drive's local indication, change the observed condition, and confirm that the NS value changes with the documented scaling. The final acceptance step is one permitted write followed by a readback of the same documented register in an approved test state.