# What Modbus register do I need to talk to a counter in iSMA-B-8I-IP?

**URL:** <https://forum.inductiveautomation.com/t/what-modbus-register-do-i-need-to-talk-to-a-counter-in-isma-b-8i-ip/98767>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [November 19, 2024, 1:42am UTC](https://forum.inductiveautomation.com/t/what-modbus-register-do-i-need-to-talk-to-a-counter-in-isma-b-8i-ip/98767 "2024-11-19T01:42:11Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![bmeyers](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/bmeyers/32/37453_2.png) [@bmeyers](https://forum.inductiveautomation.com/u/bmeyers)\
**Post date:** [November 19, 2024, 1:42am UTC](https://forum.inductiveautomation.com/t/what-modbus-register-do-i-need-to-talk-to-a-counter-in-isma-b-8i-ip/98767/1 "2024-11-19T01:42:11Z")

</div>

Hello,

I have an iSMA-B-8I-IP with following registers:

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/8/0/80f1390e1611fe997d7f5e0087c2d39e342c5f7d.png)

I want to read one of the counters but am struggling with what designator I need to pick for it in the Ignition tag configuration.

```python
ns=1;s=[iSMA_Modbus]HRI23
```

and

```python
ns=1;s=[iSMA_Modbus]HRUI23
```

both fail. My connection in the gateway shows status of connected.

Any advice on what I should try is appreciated.

---

<div class="post-metadata">

**Author:** ![ryan.white](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ryan.white/32/73193_2.png) [@ryan.white](https://forum.inductiveautomation.com/u/ryan.white)\
**Post date:** [November 19, 2024, 1:48am UTC](https://forum.inductiveautomation.com/t/what-modbus-register-do-i-need-to-talk-to-a-counter-in-isma-b-8i-ip/98767/2 "2024-11-19T01:48:44Z")

</div>

Try enabling `Zero-based Addressing` in the device connection configuration page.

Your device may also be one that requires a unit ID in front of the designator, so you could try `ns=1;s=[iSMA_Modbus]1.HRI23` or `ns=1;s=[iSMA_Modbus]255.HRI23` (1 and 255 are common device unit ID defaults, see if yours has a different default unit ID).

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<div class="post-metadata">

**Author:** ![bmeyers](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/bmeyers/32/37453_2.png) [@bmeyers](https://forum.inductiveautomation.com/u/bmeyers)\
**Post date:** [November 19, 2024, 3:09pm UTC](https://forum.inductiveautomation.com/t/what-modbus-register-do-i-need-to-talk-to-a-counter-in-isma-b-8i-ip/98767/3 "2024-11-19T15:09:50Z")

</div>

Yes, adding a unit ID of 1 to the start of it worked correctly.

```python
ns=1;s=[iSMA_Modbus]1.HRUI23
```

Thank you!