Added 6.11, 6.12, and 6.13

6-asyn-troubleshooting.md

@@ -209,8 +209,61 @@ How does the controller's response differ from [before the firmware upgrade](6-a
 
 </details>
 
-### 6.11 Confirm the communication problem
+### 6.11 Diagnose the communication problem
 
-### 6.12 Solve the communication problem
+Why doesn't the controller communicate properly with EPICS after the firmware upgrade?
+
+<details>
+<summary>answer</summary>
+
+The firmware upgrade changed the message terminator of the controller's replies.  The asyn port's input terminator, `IEOS`, is set to **\r\n** but the controller now responds with only **\r**.
+</details>
+
+### 6.12 Confirm the communication problem
+
+Correct the `IEOS` in on asynOctet.ui
+
+<details>
+<summary>solution</summary>
+
+Changing the input terminator from **\r\n** to **\r** has an immmediate effect on the messages displayed on the IOC's console: the communication is no longer delayed and the driver resumes polling at the idle polling rate.
+
+When the position is queried manually, the I/O status and severity return to `NO_ALARM` on asynOctet.ui:
+
+![screenshot of asynOctet.ui showing 1 POS? sent to the controller and a response of 400 with \r as the input terminator](images/asynOctet-positionQuery-new-fw-fixed.png)
+
+</details>
+
+### 6.13 Solve the communication problem
+
+IOC's configuration needs to be modified so the change to the input terminator persists across IOC restarts.
+
+```
+$ gedit iocsh/vmc.cmd &
+```
+
+<details>
+<summary>solution</summary>
+
+Note: this is a situation where it is **very important to include a comment explaining the change** so that the next person who maintains this IOC doesn't need to wonder why the input terminator doesn't match the virtual motor controller documentation.
+```diff
+diff --git a/iocBoot/iocxxx/iocsh/vmc.cmd b/iocBoot/iocxxx/iocsh/vmc.cmd
+index 3754207..b39d863 100644
+--- a/iocBoot/iocxxx/iocsh/vmc.cmd
++++ b/iocBoot/iocxxx/iocsh/vmc.cmd
+@@ -12,7 +12,10 @@ asynSetTraceMask("VMC_ETH", 0, 1)
+ asynSetTraceIOMask("VMC_ETH", 0, 1)
+ 
+ # Set end-of-string terminators
+-asynOctetSetInputEos("VMC_ETH",0,"\r\n")
++# Original Firmware EOS
++#!asynOctetSetInputEos("VMC_ETH",0,"\r\n")
++# New Firmware EOS
++asynOctetSetInputEos("VMC_ETH",0,"\r")
+ asynOctetSetOutputEos("VMC_ETH",0,"\r")
+ 
+ # These motor records can get their prefix from the environment variable
+```
+</details>
 
 ## [The End](README.md)