IEC 61850
Connect IEC 61850 substation IEDs over MMS - object references, the functional-constraint suffix and the supported MMS value types.
The IEC 61850 driver is not part of the current Ganter Lab download, so a station installed from that download cannot connect to an IED yet.
The IEC 61850 driver talks to substation IEDs — protection relays, merging units, bay controllers — over MMS, the client/server half of IEC 61850. You address values by their object reference in the device's data model: logical device, logical node, data object, data attribute. Add a device under the IEC 61850 driver in the Connector; the panel shows only the fields this protocol uses.
Connection
| Field | Meaning | Default |
|---|---|---|
| Host | IP address or host name of the IED. | empty |
| Port | TCP port of the MMS connection. 0 uses 102, the ISO-on-TCP standard. | 0 |
The device header shows the assembled endpoint, for example
iec61850://192.168.0.40:102. There are no poll-interval fields for this
driver: its tags are read once per second.
Addressing
An IEC 61850 tag is addressed by its MMS path in the tag's Source card:
| Field | Meaning | Accepted values | Default |
|---|---|---|---|
| MMS path | The object reference, optionally followed by a functional-constraint suffix in brackets. Required. | free text | empty |
| Read length (bytes, blank = auto) | Completes the tag's stored address form only; reads are typed MMS reads and ignore it. | 1 and up, blank | blank |
The object reference is the full path through the data model,
LogicalDevice/LogicalNode.DataObject.DataAttribute:
| MMS path | Reads |
|---|---|
LD0/MMXU1.TotW.mag.f |
total active power magnitude (a measurand, default [MX]) |
LD0/MMXU1.A.phsA.cVal.mag.f |
phase A current magnitude |
LD0/GGIO1.SPCSO1.stVal[ST] |
a single-point status value |
LD0/LLN0.Mod.stVal[ST] |
the logical device's mode |
The suffix names the functional constraint of the data attribute — the
same FC column the IED's ICD/SCL file shows. It is exactly two uppercase
letters in square brackets at the end of the path. Without a suffix, MX
(measurands) is assumed, which suits analog measurements; status values need
[ST], setpoints [SP], configuration values [CF]. Accepted tokens:
| FC | Meaning | FC | Meaning |
|---|---|---|---|
ST |
status information | EX |
extended definition |
MX |
measurands (analog) | CO |
control |
SP |
setpoint | US |
unicast sampled values |
SV |
substitution | MS |
multicast sampled values |
CF |
configuration | RP |
unbuffered report |
DC |
description | BR |
buffered report |
SG |
setting group | LG |
log control blocks |
SE |
setting group editable | SR |
service response / tracking |
OR |
operate received | BL |
blocking |
A path whose FC does not match the attribute's actual constraint fails the read, so when a value stays bad, compare the suffix against the SCL file before doubting the path. The Source card's read-only Source address (wire) line shows the assembled address as you edit.
Data types
The Data type picker offers the four primitive MMS values the driver marshals, each read with a typed MMS read:
| Data type | MMS value | Notes |
|---|---|---|
| Float | floating point | the usual choice for mag.f measurands |
| Boolean | boolean | single-point status like stVal of an SPS |
| Int32 | integer | narrowed from the MMS integer; a value beyond 32 bits fails the read |
| String | visible string | names, vendor strings, dU descriptions |
Composite values are not readable as one tag: a whole data object, a quality
bit string or a timestamp does not fit the four primitives above. Address the
primitive leaf attribute you need, like the mag.f or stVal leaf itself.
Writes
Tags whose Access is Read and write or Write only can be written. A write
sends the typed MMS value to the same object reference and functional
constraint — suitable for setpoints ([SP]) and other writable attributes.
Writes are plain MMS writes: the driver does not run the IEC 61850 control
model, so commands to Oper/SBO controls of CO attributes are not what
this is for. A new tag starts as Read only.
Discovery
IEC 61850 self-description is not wired to a scan in this driver, so the Connector shows no Discover button. Take the object references from the IED's SCL/ICD file and add the device and its tags by hand.
Good to know
- Values are polled over MMS once per second; buffered and unbuffered reporting (RCBs), GOOSE and sampled values are not used.
- The MMS connection is unencrypted ISO-on-TCP; TLS is not part of this driver's build.
- An unreachable IED costs nothing at startup: the device keeps retrying in the background and its tags read as bad quality until the connection lands.