# 14.6 IEC 60870-5-104 Slave
Since firmware version 1.8.3, multiple signals with different data types can have the same ioa address.
IEC 60870-5-104 Slave is designed not to lose data acquired from Master protocols. The data that arrives from Master protocols is stored in the cache. This data is checked every second to manage further data sending. The data that leaves IEC 60870-5-104 Slave has output caches. They’re built to provide switching between multiple sessions (redundant SCADA). If a new connection arrives, the old one is dropped, but data, that is stored in a cache, not sent and not confirmed by SCADA is transferred to the new connection. #### Configuring IEC 104 Slave data points To use IEC 60870-5-104 Slave in WCC Lite, it has to be configured via an Excel configuration. This configuration contains two Excel sheets where parameters have to be filled in Devices and Signals. ##### IEC 60870-5-104 Slave parameters for *Devices* tab**Parameter** | **Type** | **Description** | **Required | **Default value** (when not specified) | **Range** | |
Min | Max | |||||
name | string | User-friendly name for a device | Yes | |||
description | string | Description of a device | No | |||
device\_alias | string | Alphanumeric string to identify a device | Yes | |||
enable | boolean | Enabling/disabling of a device | No | 1 | 0 | 1 |
protocol | string | Protocol to be used | Yes | IEC 60870-5-104 slave | ||
asdu\_size | integer | Common address size in bytes | No | 2 | 1 | 2 |
time\_sync | boolean | Enable/disable (1 or 0) time synchronization | Yes | |||
port | integer | TCP port | No | 2404 | 0 | 65535 |
ioa\_size | integer | Information object address (IOA) size in bytes | No | 3 | 1 | 3 |
swt | integer | Send window (SWT) | No | 12 | ||
rwt | integer | Receive window (RWT) | No | 8 | ||
cot\_size | integer | Cause of transmission (COT) size in bytes | No | 2 | 1 | 3 |
host | string | Space-separated remote host IP addresses (ipv4) | Yes | |||
bind\_address | string | Bind to local IP address (ipv4) | No | 0.0.0.0 | ||
t1 | integer | Acknowledge timeout t1 (sec) | No | 15 | 1 | 255 |
t2 | integer | Connection ACKRSN clock t2 (sec), t2 should be less than t1 | No | 10 | 1 | 254 |
t3 | integer | Connection TESTFR clock t3 (sec) | No | 20 | 1 | 172800 |
message\_size | boolean | The maximum length of a message | No | 253 | 0 | 255 |
cache\_size | integer | Amount of data to be cached | No | 100 | 0 | 1000 |
tls | boolean | Enable/disable the use of TLS | No | 0 | 0 | 1 |
tls\_local\_certificate | string | Local certificate for TLS connection | Yes (for TLS) | |||
tls\_peer\_certificate | string | Certificate authority file for TLS connection | No | |||
tls\_private\_key | string | A file consisting of the private key for TLS connection | No | |||
command\_timeout\_ms | integer | Time to execute a command before responding negatively. | No | 30000 | 0 | |
command\_age\_ms | integer | The amount of time shift allowed for the command to still be executed. | No | 0 | 0 |
**Parameter** | **Type** | **Description** | **Required | **Default value** (when not specified) | **Range** | |
Min | Max | |||||
signal\_name | string | User-friendly signal name | Yes | |||
device\_alias | string | Alphanumeric string to identify a device | Yes | |||
signal\_alias | string | Unique alphanumeric name of the signal to be Yes used | Yes | |||
source\_device\_alias | string | device\_alias of a source device | For commands | |||
source\_signal\_alias | string | signal\_alias of a source signal | For commands | |||
enable | boolean | Enabling/disabling of an individual signal | No | 1 | 0 | 1 |
log | integer | Allow signal to be logged. If the **log is 0, the signal** will not be logged. If the **log is more than 0, the** signal will be logged | No | 0 | 0 | 1 |
gi | boolean | Including/excluding (1 or 0) signals from General Interrogation | No | 0 | 0 | 1 |
common\_address | integer | Address of a destination device | Yes | |||
info\_address | integer | Information object address | Yes | |||
data\_type | integer | ASDU type id. | Yes | 1, 3, 5, 9, 11, 13, 21, 30, 31, 32, 34, 35, 36, 45, 46, 47, 48, 49, 50, 58, 59, 60, 61, 62, 63 | ||
select\_ms | integer | Time limit in milliseconds for command execution. Command selection has to be performed before execution if this parameter is specified. Direct command execution can be performed only if this field is left empty or set to zero. | No | 0 | ||
periodic\_update\_ms | integer | Signal value is published periodically according to the value set. | No | - | - | - |
tag\_job\_todo | string | The device status signal can be configured by providing given value | No | No | communication\_status |