# Address configuration for s7 1200 as OPC device **URL:** \ **Category:** Ignition\ **Created:** [September 28, 2024, 10:17pm UTC](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-as-opc-device/96583 "2024-09-28T22:17:09Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![gary\_truell](https://avatars.discourse-cdn.com/v4/letter/g/48db29/32.png) [@gary\_truell](https://forum.inductiveautomation.com/u/gary_truell)\ **Post date:** [September 30, 2024, 9:45pm UTC](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-as-opc-device/96583/21 "2024-09-30T21:45:32Z")
Kevin, Sorry, that was not the correct error message for code like [Test Stand - S7 1200 Mdbs]DB5,X1.0 its ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/a/a/aa406ad229f460fdb24221a099ec443955fcbd70.png) ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/7/678b878b392064a9cba1ffce99ff522bc8e6b7e3.png) ---
**Author:** ![michael.flagler](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/michael.flagler/32/26272_2.png) [@michael.flagler](https://forum.inductiveautomation.com/u/michael.flagler)\ **Post date:** [September 30, 2024, 9:47pm UTC](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-as-opc-device/96583/22 "2024-09-30T21:47:45Z")
It looks like you're still trying to use the Modbus driver (just going off of your device name). You absolutely **CANNOT** interchange the 2 for syntax of addresses. ---
**Author:** ![gary\_truell](https://avatars.discourse-cdn.com/v4/letter/g/48db29/32.png) [@gary\_truell](https://forum.inductiveautomation.com/u/gary_truell)\ **Post date:** [October 1, 2024, 2:14pm UTC](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-as-opc-device/96583/23 "2024-10-01T14:14:54Z")
Looks like there is a limit the forum lets me post in a day. Continuing... Michael, That makes sense, but neither works as the examples say. I have tried everything I can find for both and nothing seems to work. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/8/98247097089c6bbb07bae723c0714dee1ab664aa.png) What is the correct syntax for controlling a bit using either the Simens driver or modbus on a S7 1200? Or, Better yet, how does the addressing feature work? Where are the coils being changed in the PLC? I don't see them change in offset 1, or anywhere else. What starting address should I put in to start at offset 1.0 (or any offset) ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/d/b/db7166eea7e24cc510032c42fe7302502c630e34.png) ---
**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:** [October 1, 2024, 2:20pm UTC](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-as-opc-device/96583/24 "2024-10-01T14:20:39Z")
> [@gary\_truell](#): > > correct syntax for controlling a bit Based on your earlier error report, the Modbus implementation in Siemens doesn't support the necessary "Masked Write" function code to change bits in holding registers, and doesn't support the coil function codes. So, no can do with Modbus. It should be possible with the native driver using boolean tag syntax as Kevin suggested in [comment #17 above](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-as-opc-device/96583/17), as long as you satisfy all of the preconditions for the native driver's use with S7 1200/1500 devices: > **[Siemens | Ignition User Manual](https://www.docs.inductiveautomation.com/docs/8.1/ignition-modules/opc-ua/opc-ua-drivers/siemens#considerations-for-1200-and-1500-devices)** > > The Siemens drivers in Ignition support basic connections to S7 devices. Ignition connects to these PLCs via TCP/IP using the S7 protocol. Similar to Modbus and some Allen Bradley connections, the Siemens S7 devices do not support tag browsing. You... (An S7+ driver is coming in Ignition v8.3, which should simplify this considerably.) ---
**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:** [October 1, 2024, 2:28pm UTC](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-as-opc-device/96583/25 "2024-10-01T14:28:18Z")
Also, in spite of the documentation and training material, it is **not** recommended to **ever** use the Modbus driver's "Address Configuration" tool. Just create Ignition OPC tags with manually-constructed OPC Item Paths. If you are desperate to have browsable items, consider my alternate driver, which presents the standard OPC item paths in the browse tree. ---
**Author:** ![gary\_truell](https://avatars.discourse-cdn.com/v4/letter/g/48db29/32.png) [@gary\_truell](https://forum.inductiveautomation.com/u/gary_truell)\ **Post date:** [October 1, 2024, 6:29pm UTC](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-as-opc-device/96583/26 "2024-10-01T18:29:42Z")
> [@pturmel](#): > > It should be possible with the native driver using boolean tag syntax as Kevin suggested in [comment #17 above](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-as-opc-device/96583/17), as long as you satisfy all of the preconditions for the native driver's use with S7 1200/1500 devices: I agree, it should work but it doesn't. The reason I am in the forum is because its not working as it should and so I am showing what I am doing to see why it doesn't work. The Siemens driver appears to be working, I can see the PLC name in Ignition but none of the other commands, like X1.1, work. All I get is 'Bad' for the value. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/e/6/e6c1852b30a16a5cd119182c4693ea72fb56bf83.png) ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/e/7/e7048be9495ed441323081963d85c88ccc738140.png) ---
**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:** [October 1, 2024, 6:31pm UTC](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-as-opc-device/96583/27 "2024-10-01T18:31:45Z")
> [@gary\_truell](#): > > it should work but it doesn't And you've configured the PLC to allow GET/PUT operations? And **disabled** optimized block access? (That is, followed the checklist that I linked?) ---
**Author:** ![gary\_truell](https://avatars.discourse-cdn.com/v4/letter/g/48db29/32.png) [@gary\_truell](https://forum.inductiveautomation.com/u/gary_truell)\ **Post date:** [October 1, 2024, 8:53pm UTC](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-as-opc-device/96583/28 "2024-10-01T20:53:27Z")
That was it. Thanks for your help! [Previous page](https://forum.inductiveautomation.com/t/address-configuration-for-s7-1200-as-opc-device/96583.md?page=1)