Configure a parallel cluster on the YUNT Mars PCS

About this procedure

YUNT Mars PCS units in parallel operate as one master and its slaves. The master receives one active power setpoint for the full group. The master divides this setpoint equally between itself and each slave. A slave ignores a setpoint that the LoggerV writes directly to it.

In a parallel cluster, the LoggerV adds the plant control requests of all the units. Then the LoggerV writes the total to the master only.

All the units in a cluster must be on the same DC bus. A unit that is not in a parallel cluster receives its own setpoint, as before.

Examine the roles

The master and slave roles are PCS settings. The installer sets these roles on each unit before the LoggerV controls the group.

On the device page of each unit, open Actual Data → System Status.
Make sure that Module Master/Slave Status shows Master on one unit only.
Make sure that Module Master/Slave Status shows Slave 1 on all the other units.
On the master, make sure that Parallel Quantity shows the number of units in the group. This number includes the master.
On each slave, make sure that Parallel Quantity shows 1.

Note: Each slave shows Slave 1, also when the group has more than one slave. A master with three slaves shows a Parallel Quantity of 4.

Note: A unit that shows Standalone is not on the parallel link. The cluster does not include this unit. This unit receives its own setpoint, as before.

Enable the cluster

Do these steps on each unit in the group, the master and all the slaves.

Open Settings → Parallel Cluster.
Set Parallel cluster enable to on.
Set Cluster ID to the same number on all the units that the same parallel sync cables connect.
If one LoggerV or one RS485 line has more than one cluster, give each cluster a different Cluster ID.
Make sure that each unit in the group is in plant control.
Enable each unit of the group in plant control.

Note: A user with the basic permission can change these two settings.

Note: The LoggerV does not include a unit in the total if plant control does not control that unit. But the master still gives that unit a share. Thus the group supplies less power than plant control requests.

Make sure that the cluster operates correctly

On the master, Actual Data → System Status → Cluster Setpoint shows the last total that the LoggerV wrote to the master, in kW. On each slave, this value is 0.

The applied power of each unit in plant control is the total divided by the Parallel Quantity of the master. For example, a Cluster Setpoint of 10.1 kW on four units gives 2.525 kW on each unit.

The LoggerV writes the total again when the total changes by 100 W or more. The LoggerV also writes the total again when the units in the group change.

Cluster events

Each unit shows its cluster events under Events in the device menu.

Parallel cluster suspended, "No unit in parallel cluster 1 reads Master":
- This event occurs on each connected unit in the group.
- The LoggerV writes no setpoint until one unit shows Master again.
- Make sure that the master has a connection to the LoggerV.
- Make sure that the master still shows Master.
Parallel cluster suspended, "More than one unit in parallel cluster 1 reads Master":
- This event occurs on each master.
- The LoggerV writes the request of each master to that master only.
- Set Master on one PCS only.
Parallel cluster resumed:
- The group has one master again.
- The LoggerV writes the total setpoint to the master again.
Parallel cluster size mismatch, "Master sees 3 units, parallel cluster 1 has 2 live units":
- This event occurs on the master.
- The master divides the total between the units that it sees.
- Make sure that each slave has a connection to the LoggerV.
- Make sure that Parallel cluster enable is on for each slave.
- Make sure that each slave has the same Cluster ID as the master.
- Enable each slave in plant control.
Parallel cluster size mismatch cleared:
- The master and the cluster have the same number of units again.