Danfoss AK-SM 800A Configuration of Modbus User Guide
- June 1, 2024
- Danfoss
Table of Contents
Danfoss AK-SM 800A Configuration of Modbus
Product Information
The AK-SM 800A is a System Manager device with Modbus communication
capabilities. It features two Modbus channels, each with independent
configuration properties and workflow.
Specifications
- Number of Polls: Number of times the SM attempts a request during scan
- No. of Modbus Scan Ranges: Up to 3 ranges can be configured
- Baud Rate: Default at 38400, can be changed to 19200
Product Usage Instructions
To configure Modbus Channel 1:
- Enable the channel for the System Manager to connect to controllers.
- Set the Number of Polls to determine how many times the SM should attempt a request during scan.
- Configure the No. of Modbus Scan Ranges to specify the address ranges to be scanned.
- Adjust the baud rate if needed, keeping in mind that enabling SLV/CSENSE mode reduces it to 19200.
Modbus Channel 2 Configuration
To configure Modbus Channel 2:
- Enable the channel and set up ranges for scanning.
- Define configurations with specific settings like Baudrate, Parity, Databits, and Timeout.
- The System Manager will sequentially scan addresses based on the defined configurations until a device is identified.
FAQ
How do I set up a Gmail connection in an AK-SM 800A?
To set up a Gmail connection:
- Click on the gear wheel next to the address.
- In the page that opens, click on the gear wheel again to select the correct controller from the list available to the System Manager.
Operating Guide
Configuration of Modbus on AK-SM 800A
Description
The AK-SM 800A sw. 3.2.6 is equipped with 2 Modbus channels, where we recommend:
- Modbus Channel 1 for Danfoss products
- Modbus Channel 2 for 3rd party products
They both have independent conguration properties and workow.
First of all the channel has to be enabled for the System Manager to connect to controllers. Once this is done the settings related to this will be presented for the user to choose.
Number of Polls:
Number of times the SM should try to attempt a request during scan
No. of Modbus Scan Ranges:
To reduce the amount of time taken when scanning it is possible to set up the
ranges of address that is used at the site. It is possible to configure up to
3 ranges, and only these will be scanned by System Manager. Once the user
choses to set up a range, it is the possible to configure a Low and high end
for that range.
By default, the AK-SM 800 Modbus 1 channels has a set of attributes it is
programmed with, for the user it is only possible to change the baud rate from
38400 to 19200 baud.
When SLV/CSENSE mode is enabled, the baud rate of this Modbus channel will be
reduced to 19200.
Modbus channel 2
The Modbus channel 2 is only available in the later versions of AK-SM 800A, the unit used in this guide is of application version 3.2.6. And the intention is to use the Modbus 2 channel for 3rd party products that might have different communication attributes than the standard used in Danfoss ADAP- KooL® family.
Like the Modbus 1 channel, this one also has to be enabled and it also
possible to setup ranges, and they will be used for each configuration that is
used on this channel.
The special part regarding the Modbus 2 channel is that, the user can define
what configuration should be used. It is possible to configure up to 5
different ones.
Example:
The user configures 2 configurations with the following details:
| Modbus Configuration 1| Modbus Configuration 2
---|---|---
Baudrate| 38400| 19200
Parity| Even| None
Databits| 8| 8
Timeout (ms)| 200| 100
With this setup the System Manager will scan address 1 on the first
configuration, then on the second configuration, and so on. Once it has either
found a device or if no device has responded to the scan messages it will move
on to the next address.
If a device has responded with an error message, it means that it is not the
expected device type.
In this case several messages are sent to try and positively identify the
device type. If it can’t be identified, it will be marked as an unknown
device. This can then manually be changed in the scan status, where an ed3
file can be selected to use for this device. This however only applies to
generic third-party devices, i.e. device types that are not normally
supported.
-
Click on the gear wheel next to the address
-
On the page that opens click on the gear wheel again to get the list of controllers that are available to that particular System Manager and select the correct one.
The Modbus settings that a device was discovered on is stored, so that any
subsequent messages to this device are sent using the correct Modbus settings.
Because there is some overhead with switching Modbus configurations, it is
recommended to use the least number of configurations needed for the system.
Note
- Schneider meters works only on Modbus channel 1, at 19200 for the moment.
- Do not use Danfoss controllers with auto baud rate detection Modbus 2 channel with more than one configuration, as the controllers will respond to both configurations.
Danfoss A/S
Climate Solutions • danfoss.com • +45 7488 2222
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