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M1-Modbus-Bug.md

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+# M1 Modbus Bug
+
+When adding more than one register that uses the multiplier feature, there is an error in the processing of the value. This is logged to the console:
+
+```python
+error reading modbus value
+No communication with the instrument (no answer)
+Error reading register, retries exhausted
+local variable 'val' referenced before assignment
+Sending log to log-modbus: (X) Retries Exhausted: local variable 'val' referenced before assignment
+```
+
+## Steps to re-create the error
+
+1. Set up a single channel with no multiplier value.
+
+2. Set Modbus settings and Sync to Device.
+
+    ```
+    here is the answer
+    <20><>
+    '\xf7\x03\x02\x13\x16\xfc\xaf'
+    '\xf7\x03\x02\x13\x16\xfc\xaf'
+    here is the payload from slave
+
+    '\x02\x13\x16'
+    here is the payload
+
+    '\x02\x13\x16'
+    success reading
+    4886
+    4886
+    ```
+
+3. Set up another channel with Multiplier parameter of "Divide" and Multiplier Value of "10".
+
+4. Sync to Device.
+
+    on first register:
+
+    ```
+    here is the answer
+
+    ''
+    ''
+    error reading modbus value
+    No communication with the instrument (no answer)
+    had an error on the modbus loop, retrying read
+    here is your period:  120
+    23.4706990719
+    here is your send value:  False
+    getting int
+    writing 485:  <20>,P<>
+    ```
+
+    on second register:
+
+    ```
+    here is the answer
+
+    ''
+    ''
+    error reading modbus value
+    No communication with the instrument (no answer)
+    Error reading register, retries exhausted
+    local variable 'val' referenced before assignment
+    here is your period:  120
+    1525193769.02
+    here is your send value:  True
+    getting int
+    writing 485:  <20>7 <20>
+    ```
+
+
+
+