EMS Modbus

Read or write registers on the EMS by address. The EMS accepts a client write only while its control mode is scada_control or external_control; a read is always answered.

Control mode local_control (0) — the EMS keeps the previous value for any client write and still answers success. Change the control mode on the EMS frontend to have writes applied.

Mode

Read fetches what each row's address currently holds, from the same target below. Write sends the value you type. Either way a row is used only when it carries an address.

Target

Look up a register →

The Modbus server every row is read from or written to. ems-backend:1540 is this stack's own EMS; another host or port aims the same form at a different one.

# Address Register Type Byte order Value
1 Look up →
2 Look up →
3 Look up →
4 Look up →
5 Look up →
6 Look up →
7 Look up →
8 Look up →
9 Look up →
10 Look up →
Rows with an address are used; blank rows are ignored.

Each value is encoded exactly as the EMS server decodes it, including the byte order, then read back and compared with what you asked for. A value that did not change means the EMS did not accept the write.

Rows you fill in are kept in this browser tab, so going off to look a register up does not empty the rows you have already filled. Closing the tab discards them.