# Unable to connect Idec Smart Relay(FL1F-H12RC) Over Modbus TCP Connection

**URL:** <https://forum.inductiveautomation.com/t/unable-to-connect-idec-smart-relay-fl1f-h12rc-over-modbus-tcp-connection/99396>\
**Category:** Ignition\
**Created:** [December 4, 2024, 5:28am UTC](https://forum.inductiveautomation.com/t/unable-to-connect-idec-smart-relay-fl1f-h12rc-over-modbus-tcp-connection/99396 "2024-12-04T05:28:35Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![dhiraj.pawar](https://avatars.discourse-cdn.com/v4/letter/d/3ec8ea/32.png) [@dhiraj.pawar](https://forum.inductiveautomation.com/u/dhiraj.pawar)\
**Post date:** [December 4, 2024, 5:28am UTC](https://forum.inductiveautomation.com/t/unable-to-connect-idec-smart-relay-fl1f-h12rc-over-modbus-tcp-connection/99396/1 "2024-12-04T05:28:35Z")

</div>

Hello Team,  
We are trying to connect Smart Relay(FL1F-H12RC) over Modbus TCP connection, We are unable to connect to Smart Relay(FL1F-H12RC) over Modbus TCP & getting below error on gateway log.

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/f/d/fd584983bdc95e95fb441944737b191e768dde80.png)

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/8/c/8cb68e3dec96244f2d16ee57317059686d66a841.jpeg)  
[Ignition-PIND6IGN01\_thread\_dump20241204-105034.json](https://forum.inductiveautomation.com/uploads/short-url/7UiSvAbdhAgeFG9SNFTKovVk0Ql.json) (346.8 KB)

Please find the attached log file for your reference.

Ignition Version : 8.1.28

Thanks in advance for quick support

Regard,  
Dhiraj Pawar

---

<div class="post-metadata">

**Author:** ![David\_Stone](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/david_stone/32/79749_2.png) [@David\_Stone](https://forum.inductiveautomation.com/u/David_Stone)\
**Post date:** [December 4, 2024, 9:51am UTC](https://forum.inductiveautomation.com/t/unable-to-connect-idec-smart-relay-fl1f-h12rc-over-modbus-tcp-connection/99396/2 "2024-12-04T09:51:01Z")

</div>

Possibly share your configuration of the settings in the Modbus Driver, as well as the tags you are using.

---

<div class="post-metadata">

**Author:** ![Jesus\_Rios](https://avatars.discourse-cdn.com/v4/letter/j/edb3f5/32.png) [@Jesus\_Rios](https://forum.inductiveautomation.com/u/Jesus_Rios)\
**Post date:** [December 31, 2024, 5:59pm UTC](https://forum.inductiveautomation.com/t/unable-to-connect-idec-smart-relay-fl1f-h12rc-over-modbus-tcp-connection/99396/3 "2024-12-31T17:59:40Z")

</div>

Hello,

We are currently trying to connect to an IDEC Smart Relay (FL1F-H12RCE) over Modbus TCP using Ignition and we are not being successful either. Wondering if you had any luck communication with the Smart Relay over Modbus TCP using ignition? I am starting to think that IDEC Smart Relay is able to communicate over Modbus TCP with other IDEC Smart Relays only.

---

<div class="post-metadata">

**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [December 31, 2024, 6:12pm UTC](https://forum.inductiveautomation.com/t/unable-to-connect-idec-smart-relay-fl1f-h12rc-over-modbus-tcp-connection/99396/4 "2024-12-31T18:12:08Z")

</div>

I would guess that Ignition's default to unit #0 is the problem. Based on the address map I just downloaded, which indicates one-based addressing, try these OPC Item Paths (direct in a tag, not in the address mapper):

- `[device]1.DI1` for **I1**
- `[device]1.C8193` for **Q1**
- `[device]1.C8257` for **M1**
- `[device]1.C1` for **VB0.0**
- `[device]1.IR1` for **AI1**
- `[device]1.HR1` for **VW0**
- `[device]1.HR513` for **AQ1**
- `[device]1.HR529` for **AM1**