sourceperl · November 5, 2024 17:07 · Nov 5, 2024
diff --git a/multi_uid.py b/multi_uid.py
@@ -0,0 +1,39 @@
+import time
+from collections import defaultdict
+from typing import Dict
+
+from pyModbusTCP.server import DataBank, ModbusServer
+
+
+class MyDataBank(DataBank):
+    class Data:
+        def __init__(self) -> None:
+            self.h_regs = {}
+
+    def __init__(self):
+        # turn off allocation of memory for standard modbus object types
+        # only "holding registers" space will be replaced by dynamic build values.
+        super().__init__(virtual_mode=True)
+        # public
+        self.uids: Dict[int, MyDataBank.Data] = defaultdict(MyDataBank.Data)
+
+    def get_holding_registers(self, address: int, number: int, srv_info: ModbusServer.ServerInfo):
+        # returns None if any of the registers are missing
+        try:
+            req_uid = srv_info.recv_frame.mbap.unit_id
+            return [self.uids[req_uid].h_regs[addr] for addr in range(address, address+number)]
+        except KeyError:
+            return
+
+
+if __name__ == '__main__':
+    # init a custom data bank, fill it with static data for unit id #1
+    data_bank = MyDataBank()
+    data_bank.uids[1].h_regs[0] = 42
+    # init modbus server and start it
+    ModbusServer(host='localhost', port=5020, data_bank=data_bank, no_block=True).start()
+    # update dynamic data at @0 for unit id #2
+    while True:
+        for i in range(1_000):
+            data_bank.uids[2].h_regs[0] = i
+            time.sleep(0.1)